Starship Asterisk*

The Kepler spacecraft has found over 750 candidates for extrasolar planets, and that is just from data collected in the first 43 days of the spacecraft's observations. "This is the biggest release of candidate planets that has ever happened," said William Borucki, Kepler's lead scientist. "The number of candidate planets is actually greater than all the planets that have been discovered in the last 15 years."

This is an astounding amount of potential exoplanets from data taken during such a short period of time, however Borucki added that they expect only about 50% of these candidates to actually turn out to be planets, as some may be eclipsing binary stars or other artifacts in the data. But still, even half would be the biggest group discovery of exoplanets ever.

And the exciting part is that 706 targets from this first data set have viable exoplanet candidates with sizes from as small as Earth to around the size of Jupiter. The team says the majority have radii less than half that of Jupiter.

The Kepler team has found so many candidates, they are sharing. They will keep the top 400 candidates to verify and confirm with observations using other telescopes – with observations done by Kepler team members. And today they have released the other 350 candidates, including five potential multiple planet systems.

However, some astronomers are upset about this and think the Kepler team should release all of their findings from the first year, as is typically done with NASA data.

• Papers of Interest:
  
  Characteristics of Kepler Planetary Candidates Based on the First Data Set:
  The Majority are Found to be Neptune-Size and Smaller
  • lanl.arXiv.org > astro-ph > arXiv:1006.2799 > 14 Jun 2010
  Five Kepler target stars that show multiple transiting exoplanet candidates
  • arXiv.org > astro-ph > arXiv:1006.2763 > 14 Jun 2010

Today should be a historic moment for the field of astronomy. With a single data release, the team behind NASA's Kepler instrument has nearly doubled the number of extrasolar planets we're aware of, including many that fall between the sizes of Earth and Neptune, a class of planets that was poorly represented in our existing collection. Instead, NASA's handling of the announcement appears to have been very confused, and attention will likely focus on the candidate planets that were left out: 400 objects that are even smaller than the ones being announced.

The decision to hold back on the most Earth-like objects had been made months ago. The intent is to allow the project scientists the chance to confirm these are not false positives and to have priority in publishing on the exoplanets. These candidates are mentioned only once in a draft paper that describes the data that is being released. Referring to Earth's radius as Re, the draft states, "those [stars] with the small-size candidates (ie, those with radii less than 1.5 Re), are among the 400 withheld targets and are thus not among those considered here."

That controversy aside, NASA's handling of the data release has been positively bizarre. Word of the hundreds of new planets in the data release appears to have been first disclosed by The New York Times. A NASA video describing the data appeared briefly on YouTube, but was then pulled, while two draft papers that describe some of the results appeared in the arXiv last night.

But, despite the apparent publicity, NASA has remained silent. There have been no releases about the data, and NASA's Kepler mission page still lists its planet count as an anemic five. It's not clear what exactly is going on with the space agency.

The planet-hunting space telescope, Kepler, released its first big batch of data today.

That should be exciting, but the team held back the good stuff until February 2011, wanting to analyze and follow up on the early observations themselves. Kepler is trying to find Earth-like planets that exist at just the right distance from their home stars to retain water in liquid form.

Of the 156,000 target stars in the telescope’s field of vision, the 43 days of observations found 706 possible extrasolar planets from Earth size up to a bit bigger than Jupiter. Today, the NASA Ames Research Center crew, led by William Borucki, released data on the 306 targets they’re least excited about. Their top 400 candidates to investigate as possible Earth twins will not be announced for eight more months.

“Many of the candidates are likely to be false positives and the brighter stars, and those with the small-size candidates … are among the 400 withheld targets and are thus not among those considered here, biasing the results toward the dimmer stars and larger candidates,” Borucki wrote in an article posted to arXiv.org.

The data release plan was approved earlier this year by a special NASA advisory board, but has recently touched off controversy over its fairness and wisdom.

Space telescope finds evidence of planets around hundreds of stars

Surveying thousands of stars for telltale twinkles that signal the passage of an orbiting planet, NASA’s Kepler spacecraft has discovered a whopping 706 candidate planets beyond the solar system. If confirmed, that motherlode would boost the number of known extrasolar planets, now estimated at 460, to well over a thousand.

The trove, announced June 15, includes evidence of five stars that have full-fledged planetary systems. These exoplanet systems, if verified, would be the first known in which each planet creates a minieclipse as it transits, or passes in front, of its parent star. The amount of dimming and the duration of a transit offer information about planets, including their size, that cannot be gleaned by less direct methods of detection.
...
The newly reported findings don’t include details about the most interesting 400 of the 706 candidate planets, which orbit the brightest stars Kepler has surveyed. These cases may offer the most promise for finding planets with masses close to Earth‘s own. Information on these 400 planets won’t be made public until next February.

One of the biggest astronomical stories to unfold over the last decade or so is the story of exoplanets (or "extra-solar planets"). The theory of the formation of our solar system predicts that there should be many more such systems out there. And there certainly are, in fact, 461 at time of writing.

Continuing this epic tale of discovery, the Kepler Mission announced today the discovery of approximately 750 new candidates, but this announcement hasn't come without controversy.
...
The controversy comes with how the data are being released to the astronomical community, as reported on in the New York Times today. The 43-day data set contains 750 planet candidates, 350 if which will be released to the astronomical community. This is necessary to deal with the sheer number of discoveries. This is a good thing for astronomers everywhere, right?

The 400 candidates are being withheld by the Kepler team so that they can do follow-up work and publish their results. This is generally considered a fair system where the principal investigators have the data for a set amount of time before having to make it public.

It’s the 1840s. Rival astronomers in Britain and France separately toil away in their notebooks, fiercely guarding their calculations of just where a planet beyond Uranus might be hiding, hoping that they and their country will get the glory for finding it. When telescopes finally spot Neptune, the discovery leads to decades of debate over primacy, and scouring each man’s private data to determine who deserved the most credit.

Fast forward to the 21st century: Rivalries may have changed, but in the hunt for new planets—especially becoming the first to detect a new world like our own in a distant star system—defending one’s data to lay claim to discovery has not gone away.

This week the team behind NASA’s planet-hunting space telescope, Kepler, announced that it has found more than 700 new candidates for exoplanets. Given that the current tally of known planets beyond our solar system stands near 460, that’s a huge announcement. But what’s drawn some attention is that more than half of the candidates won’t be released publicly at this time. These include smallest planet candidates—those closest to our own world in size—which won’t be officially announced until February 2011.

It’s no secret why:

“The first astronomer who can prove they found an Earthlike planet around an Earthlike star will win many kudos and prizes,” said John Huchra of the Harvard-Smithsonian Center for Astrophysics, who led a NASA advisory committee that approved the deal. “It’s glory for NASA,” he added.“NASA would like to have one of its missions find an Earthlike planet” [The New York Times].

Given all the time and effort that went into developing Kepler, most astronomers seem to be all right with the team taking its time to analyze its data and get the credit they deserve. The best viewing time to confirm many of them as true exoplanets will take place over this summer. But given the tantalizing contents of Kepler’s catalog and the potential for finding an Earth-like planet it shouldn’t be surprising if people get impatient to have their own look.

The typical planet identified by transit observations (the method used by Kepler) was about 13 Re [Earth radii]. The data that has been released includes about 100 planets that are somewhere between two and four Earth radii—and that’s excluding up to 400 smaller objects [ars technica].

In the meantime, those planets Kepler scientists have now publicized should provide fodder for curious stargazers. One new paper says that five stars the telescope studied have multiple exoplanets in orbit. Also, Europe’s CoRoT Space Telescope has added six new giant exoplanets to its own tally, and even spotted a brown dwarf.

Perhaps more eyes would speed up the search for a second Earth. However, it’s hard to blame the Kepler scientists for trying to avoid the claim-to-fame wars of the past.

Kepler is a NASA mission designed to detect exoplanets and characterize the properties of exoplanetary systems. Kepler also includes an asteroseismic programme which is being conducted through the Kepler Asteroseismic Science Consortium (KASC), whose 400 members are organized into 13 working groups by type of variable star. So far data have been available from the first 7 month of the mission containing a total of 2937 targets observed at a 1-min. cadence for periods between 10 days and 7 months. The goals of the asteroseismic part of the Kepler project is to perform detailed studies of stellar interiors. The first results of the asteroseismic analysis are orders of magnitude better than seen before, and this bodes well for how the future analysis of Kepler data for many types of stars will impact our general understanding of stellar structure and evolution.

Astronomer Dimitar Sasselov and his colleagues search for Earth-like planets that may, someday, help us answer centuries-old questions about the origin and existence of biological life elsewhere (and on Earth). How many such planets have they found already? Several hundreds.

Dimitar Sasselov works on uniting the physical and life sciences in the hunt for answers to the question of how life began.

Despite overzealous news headlines this week, NASA's Kepler spacecraft has not indentified more than 100 Earth-like planets in the galaxy.

The planet-hunting telescope, launched in April 2009, has so far confirmed only five alien planets beyond the solar system, mission scientists told SPACE.com.

The erroneous reports of new planets were generated in response to a recent videotaped speech Kepler co-investigator Dimitar Sasselov gave at a TED (Technology Entertainment and Design) conference in July.

"More than 100 'Earth-like' planets discovered in past few weeks," read the headline of a Wednesday article in the U.K.'s Daily Mail newspaper. The Observer, another U.K. paper, also reported the finding.

However, Sasselov was referencing only possible planets among the Kepler data, scientists said.

"What Dimitar presented was 'candidates,'" said David Koch, the mission's deputy principal investigator at NASA's Ames Research Center in Moffett Field, Calif. ...

Koch confirmed that Kepler's official planet tally is still much lower. "Other than the 5 planets previously published, we have not announced anything else," he said.

However, Sasselov did say that what Kepler has learned so far about extrasolar planets offers tantalizing hints that our planet may not be unusual.

Among the hundreds of candidate planets, a large percentage of them appear to be Earth-like – that is, small and rocky, rather than large and gassy, like Jupiter.

"Even before we have confirmed the planets among these hundreds of candidates, we can see statistically that the smaller-sized planets will be more common than the large-sized (Jupiter- and Saturn-like ones) in the sample," Sasselov explained.

That's good news for scientists who hope to one day detect life on another planet. Since life as we know it is thought to require water and Earth-like conditions, planets that look a lot like ours could be habitable.

• Reader note: "These articles were sparked by a talk that was given by Harvard's Dimitar Sasselov at TEDGlobal at Oxford this month. It was posted to the TED site last week and picked up by various sites: link. The smoking gun is the slide in the background at about 8:15 in the talk."
  

  

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• Keith's note: Here is the slides - plus another. Now I see where the story had is origin - so Fox and the other papers are off the hook - although they did manage to scramble things a bit. I think Sasselov's use of English is at fault here. Also, my original comments about the Kepler team's PR skills have been underscored by this fumbled release of stunning news.

How odd that this venue was chosen - one where you have to pay thousands of dollars to get in - in a foreign country - as the place where this announcement is made by Kepler Co-Investigator Dimitar Sasselov. What is really annoying is that the Kepler folks were complaining about releasing information since they wanted more time to analyze it before making any announcements. And then the project's Co-I goes off and spills the beans before an exclusive audience - offshore. We only find out about it when the video gets quietly posted weeks later.

If Dimitar Sasselov is allowed to give an exclusive update to a high-priced, hand-picked audience in the UK, then the Kepler project should seek to give the rest of us here back in the U.S. an update on the amazing discoveries Kepler has made. Not to do so - immediately - will call into question the agency's avowed intent to be open and transparent to the very people who pay the bills for these missions. Indeed, a disclosure such as Sasselov's already makes the Kepler mission team's rationale for not releasing data sound hollow.

This is amazing, paradigm-shifting, stuff, NASA. Everyone wants to know more. Set the Kepler data free.

Here is what Sasselov said (transcript reflects his less than perfect use of English):

What the new telescope Kepler has been able to tell us in the past few weeks - and lo and behold - we are back to the harmony and to fulfilling the dreams of Copernicus. You can see here [Chart] - small planets dominate the picture. The planets which are marked "like Earth" - definitely more than any of the other planets that we see. Now for the first time we can say that. There is a lot more work we need to do with this. Most of these are candidates and in the next few years - we will confirm them - but the statistical result is loud and clear - and the statistical result is that planets like our own Earth are out there. [Chart] Our Milky Way galaxy is rich in this kind of planet. So the question is what do we do next? Well we can study them now. We know where they are. And we can find those that we call "habitable" meaning that they have similar conditions to what experience here on Earth and where a lot of complex chemistry can happen ...

• NASA's Deep Space Camera Locates Host of 'Earths', Fox
  
  "Scientists celebrated Sunday after finding more than 700 suspected new planets -- including up to 140 similar in size to Earth -- in just six weeks of using a powerful new space observatory. Early results from NASA's Kepler Mission, a small satellite observing deep space, suggested planets like Earth were far more common than previously thought."
  
  Space probe locates 'Earth-like' planets, The Australian
  
  "Buried in the deluge of data sent back by the probe are clear signs that at least five of the 150,000-plus stars it has studied may have two or more planets in orbit around them. Some appear similar in size to Earth. These results emerged from the first six weeks of Kepler's mission, meaning the probe has had a chance to spot only fast-moving planets with particularly rapid orbits."
  
  Prospect of life in deep space as Nasa probe finds hundreds of new planets, Daily Mail
  
  "Hundreds of new planets have been discovered by Nasa's new space probe, sparking new hope of life outside our solar system. Up to 140 of the newly-found planets are rocky and Earth-like containing both land and water, conditions which could allow simple lifeforms to develop."
• Keith's note: Looks like Fox News, The Australian, and the Daily Mail have jumped the gun again. To read their headlines and their short stories, you'd think that a bunch of Earthlike planets have been confirmed circling other stars with "both land and water" - and that this is how NASA has been characterizing the Kepler results. Alas this is not what NASA has been saying - at least not publicly.

...

NASA didn't plan it this way, but earlier this month a co-investigator on the Kepler satellite mission in the hunt for other Earth-like planets announced to a conference in Oxford, England, that "planets like our own Earth are out there. Our Milky Way galaxy is rich in this kind of planet." The announcement—which wasn't getting out until conference organizers posted a video online last week—was especially striking because it was largely based on Kepler data that team members had been allowed to keep to themselves for further analysis until next February. So, traditionally, such data would be released formally with all involved scientists onboard.

The all-too-public leak came from astronomer and Kepler co-investigator Dimitar Sasselov of Harvard University at the annual TEDGLobal conference, a production of the nonprofit TED.

At 8:15 into his 18-minute talk, Sasselov showed a bar graph of planet size. Of the approximate 265 Kepler planets represented on the graph, about 140 were labeled "like Earth," that is, having a radius smaller than twice Earth's radius. "You can see here small planets dominate the picture," said Sasselov. Until now, astronomers' exoplanet finds had been more like gas giant Jupiter than rocky little Earth. Even Kepler investigators had refrained from discussing any Earth-size finds.

Sasselov did emphasize that these are candidates, not confirmed exoplanets. With further observation, half of them could well turn out to be false alarms. Many could also be Earth-like in size but orbiting so close to their stars that nothing but their size would be Earth-like. Sasselov said that astronomers will be able to identify at least 60 Earth-like planets. So the unauthorized presentation of preliminary results would seem to confirm that Kepler has succeeded in showing that Earth is no fluke.

NASA has yet to comment.

Data Leak: Galaxy Rich in Earth-Like Planets, Science

Claims of 100 Earth-Like Planets Not True, Space.com

Keith's note: Ok, I am confused. The charts that Sasselov showed are not what you show when you are unsure of what your data is telling you. Indeed, one chart proclaims "Kepler space telescope - the first 700 planet candidates: The Galaxy is rich in small, Earth-like planets". There is no hesitation or equivocation, this is a declarative statement that comes across as a fact i.e. "the Galaxy *IS* rich in small, Earth-like planets". You certainly would need a lot of confirmed "candidates" in order to make such a bold claim in public.

Listen again to Sasselov's words: "You can see here [Chart] - small planets dominate the picture. The planets which are marked "like Earth" - definitely more than any of the other planets that we see. Now for the first time we can say that. There is a lot more work we need to do with this. Most of these are candidates and in the next few years - we will confirm them - but the statistical result is loud and clear - and the statistical result is that planets like our own Earth are out there." He says that the "statistical result is loud and clear" in other words he has data to back up his claims.

Is the Kepler team hiding something? Why is Sasselov talking about data that the Kepler team said that they did not want to discuss yet? Does Sasselov not understand what he is talking about? Or is this an issue with a scientist with a tendency to exagerate combined with less than perfect English skills? This was a public presentation by a key Kepler scientist speaking in that capacity. Did NASA PAO screen these materials before the presentation?

The Kepler folks seem to want to have things both ways. On one hand they want to tantalize us (and select audiences) with what they have found but yet at the same time they do not want to put their reputations on the line when people start taking their comments as fact. This project clearly needs to put some PR strategy in place.

In a recent presentation, Kepler co-investigator Dimitar Sasselov preempted the official announcement that the exoplanet-hunting Kepler Space Telescope has discovered about 140 candidate worlds orbiting other stars that are "like Earth."

Usually, announcements like these happen after an official press release, but during the TEDGLobal conference in Oxford, U.K., Sasselov unexpectedly dropped the groundbreaking news in one of his presentation slides.

"You can see here the small planets dominate the picture," he casually said while referring to a graph depicting the different exoplanet sizes and their number as of July 2010.

Although he refers to these exoplanets as "candidate" Earth-like worlds, Sasselov goes on to talk about the statistical prevalence of small planets throughout the Milky Way.

Before Kepler, only the larger exoplanets could be seen. This is fairly obvious; large gas giants are easier to detect over the great interstellar distances. The highly sensitive Kepler has now leveled the playing field, indicating that there are many more exoplanets twice the size of Earth and smaller.

Undoubtedly, this is huge news. If officially confirmed by NASA -- and only then would it be advisable to pop the champagne corks -- the discovery of dozens of worlds of comparable size to Earth is historic.
...
"The statistical result is loud and clear. And the statistical result is that planets like our own Earth are out there. Our Milky Way galaxy is rich in these kinds of planets." --Dimitar Sasselov

Although some publications glossed over the uncertainty in announcing the first findings of the planet-hunting Kepler mission, researchers say the overall point remains true: Earth-like planets (meaning that they’re small and rocky, not that they have aliens writing blogs about science) are not only not rare–they’re the most common type of planet in our galaxy.

The first intimations of this news came out a few days ago in reports like the Daily Mail’s, which blared that NASA’s planet-hunting Kepler mission had found 140 new planets that were like the Earth in size, and that worlds like our own could dominate the Milky Way. That claim came after a presentation now available to view online by one of the scientists behind Kepler, Harvard’s Dimitar Sasselov.

But Sasselov and colleagues responded to Space.com, trying to quell some of the excitement–or at least hedge on the exact magnitude of the find: ... [Space.com]

The trouble arose after Kepler scientists kept a tight lip on their findings. Last month, they announced that their first round of research had found around 700 exoplanet candidates. (For comparison, there are fewer than 500 confirmed exoplanets now). But the team refused to discuss the details of about half of those planet candidates, and those are the ones most like the Earth. Given the scientific cred at stake, they wanted to analyze and publish papers before releasing data to the public.

Sasselov says he wasn’t giving out new information that wasn’t already available in papers published last month, but in the conference video he’s pretty direct about the cosmic importance of the findings, whether or not they’re merely candidates. ... [ScienceNOW]

So, yes, the astronomers need to conduct a battery of tests and analyses to make sure the signals they’ve seen truly are planets. Only five of Kepler’s 700-plus haul of candidates are officially confirmed now.

But that doesn’t mean we shouldn’t be excited. Sasselov says they should be able confirm 60 of these Earth-like candidates at the very least. And even that would change our picture of the galaxy, and mean that many more planets like our own are out there. ... [Space.com]

As his slide says during the presentation: “The galaxy is rich in small, Earth-like planets.”

bystander wrote: Kepler’s Early Results Suggest Earth-Like Planets Are Dime-a-Dozen
Discover Blogs | 80beats | 26 July 2010

Sasselov says they should be able confirm 60 of these Earth-like candidates at the very least. And even that would change our picture of the galaxy, and mean that many more planets like our own are out there. ... [Space.com]

As his slide says during the presentation: “The galaxy is rich in small, Earth-like planets.”

Our galaxy is rich in Earth-sized planets, CNN

"Since the time of Nicolaus Copernicus five centuries ago, people have wondered whether there are other planets like Earth in the universe. Today scientists are closer than ever to an answer -- and it appears to be that the Milky Way galaxy is rich in Earth-sized planets, according to astronomer Dimitar Sasselov. Drawing on new findings from a NASA telescope, he told the TED Global conference in Oxford, England earlier this month that nearly 150 Earth-sized planets have been detected so far. He estimated that the overall number of planets in the galaxy with "similar conditions to the conditions that we experience here on Earth is pretty staggering. It's about 100 million such planets."

Millions of Earths? Talk causes a stir, Alan Boyle's Cosmiclog, MSNBC

"NASA Watch's Keith Cowing said he was confused by Sasselov's seemingly significant non-news: "The Kepler folks seem to want to have things both ways," he wrote. "On one hand they want to tantalize us (and select audiences) with what they have found but yet at the same time they do not want to put their reputations on the line when people start taking their comments as fact. This project clearly needs to put some PR strategy in place." My efforts to get comments from Sasselov or other members of the Kepler team today were unsuccessful, but NASA spokesman Michael Mewhinney did tell me that the scientists are preparing a fresh response and would provide further clarification on Tuesday. So check back here for updates as they become available."

Keith's 2:28 pm EDT note: My reaction to this news is not unlike my reaction to the opening scene of the early Star Trek Enterprise episode "Strange New World" - and the crew's reaction to seeing an M-Class planet unexpectedly fill the view out a window. As Ensign Cutler comments, "You'd think that the Captain would make an announcement or something". The discussion between Captain Archer and T'Pol about Archer's impatience to see and explore the new world is equally appropriate to the current Kepler story.

ARC PAO's Michael Mewhinney and his cohorts have had several days to come up with a response. While the world is buzzing about this astonishing news we've heard nothing from the Kepler team. Someone needs to light a fire under Mewhinney et al The fact that NASA can't get its act together to address this news is baffling. Trully baffling. I can understand dragging their feet when there is bad news, but when paradigm-shifting, awe-inspiring news like this starts to circulate around our planet, the agency's inability to address it makes me wonder if the agency trully understands what it is doing - and the impact it can have on they way we view the universe.

Keith's 4:52 pm EDT update: Finally - a response from the Kepler folks - via Twitter here: "@KeithCowing We're working on it! New Kepler blog contribution from Dimitar is on its way. Will tweet the moment it's ready." and here: "@NASAWatch Kepler blog contribution from Dimitar Sasselov is expected to be out today."

Mainstream media (MSM) is funny. Well, maybe funny isn't the right word, especially when they hose things up and create a story when there really isn't one. Or when they miss the real story. MSM recently succeeded in spades on both accounts in regards to the Kepler mission. Just last month, the Kepler team announced they had found over 750 candidates for extrasolar planets, and 706 of these candidates potentially are planets from as small as Earth to around the size of Jupiter, with the majority having radii less than half that of Jupiter. This is such incredible news, especially when you factor in that the data was from just 43 days of observations! But MSM seemed to miss all this and instead focused on the fact that the Kepler team got approval from NASA to keep over half of their data for an additional six months to verify and confirm their findings, rather than releasing all of it, as per NASA's standard policy which requires astronomers to release their data from publicly funded instruments in one year. Then over this past weekend, from a TED talk by Kepler co-investigator Dimitar Sasselov, MSM finally realized that Kepler has found a boat-load of potential Earth-sized exoplanets. Well, yes. That's what they said in June.

But then MSM took things out of context and exaggerated just a tad.

Even though in his talk, Sasselov used the words "potential" and "candidates" and said the planets are "like Earth, that is, having a radius smaller than twice Earth's radius," MSM reported news that NASA has found rocky planets with land and water.

And now some people are saying that Sasselov "leaked" the proprietary Kepler data, and some say he is in trouble for doing so. Today, the Kepler team said via Twitter that they are "working hard to thoughtfully respond to the media flurry surrounding the TEDGlobal talk."

Let me use one of my mother's favorite admonitions: For Pete's sakes!

Watch the TED talk. In my opinion, Sasselov does a good job of getting people excited about exoplanets and he doesn't say we have actually found another Earth. He also does a good job of presenting what the Kepler team has found without revealing any really huge proprietary data, ...

But really, this is pretty much what the Kepler team said in June, that they expected half of the 750 planet candidates would turn out not to be planets, and a fair number of those might be Earth-sized. The graph takes into account the amount of potential planets that Kepler found, plus the planets found previously by other telescopes and missions.

While it is exciting to think about the potential of finding Earth-sized and maybe even Earth-like planets, we're likely a long way off from actually finding and then actually confirming another Earth. Additionally, right now, we're only capable of finding planets that orbit relatively close to their parent star, which most likely wouldn't put them in the "Goldilocks Zone" of being habitable.

You can read our original article from June here, where the Kepler team announced their findings. There's also an explanation there of why the team requested to keep part of their data for an extra six months.

Keith's 6:28 pm EDT note: This was just posted on the Kepler website and at NASA.gov:

Two weeks ago, I gave a talk at TED Global 2010 which was very well received, but caused confusion. I talked about Earth-like planets, which many people would equate to Earth-size and 'habitable'.

Earth-size and Earth-like is certainly not the same. Take the example of Venus, an Earth-size planet whose surface will melt lead. I understand that the term "Earth-like" was misleading to most of the media coverage. The Kepler mission is designed to discover Earth-size planets but it has not yet discovered any; at this time we have found only planet candidates.

The June 2010 Kepler data release with 306 candidates is an encouraging first step along the road to Kepler's ultimate goals, and specifically - the goal to determine the frequency of Earth-size planets in and near the habitable zone. However, these are candidates, not systems that have been verified sufficiently to be considered true planets. It will take more years of hard work to get to our goal, but we can do it.

That's all that Sasselov (NASA) as to say? It took two days to generate this? Dimitar Sasselov's Kepler statement puts the blame on other people (media are people too) misunderstanding him - not on what he clearly said. He clearly said "The Galaxy is rich in small, Earth-like planets" and "the statistical result is that planets like our own Earth are out there". These are rather bold statements for mere "candidate" planets. Moreover these words clearly evoke specific concepts in one's mind i.e. worlds - like - Earth.

If Dimitar Sasselov is going to formally represent the mission to the public then he needs vastly improve his speaking skills beyond what he currently possesses. Moreover, he needs to be reminded that this is a project funded to the tune of hundreds of millions of tax dollars. His audience is not some little club of elites but rather everyone, everywhere. Lastly, he needs to understand that 99.9% of humanity is not versed in the nuances, subtleties, and jargon that he and his fellow science majors use every day. He used the phrase "Earth-like" and he needs to admit that he made the error. For his audience to get the impression that they got is perfectly understandable given the words that he used.

This should be an object lesson to the Kepler team - and to NASA - as to how NOT to take a tantalizing topic and present it to the public. Sasselov bungled the delivery such that the world could not clearly understand what is - and is not proven as fact - yet.

Keith's 8:58 pm EDT update: Update: there is now a lengthier post by Sasselov here. I only learned about it from an alert reader. NASA PAO has not bothered to tell the media and no mention is made on any Kepler website. So I guess you have to stumble across it or just happen to see it flash by on Twitter. The essense of my complaint is the same - Sasselov claims that this was all a misunderstanding by the media - not poor choice of words and lack of through explanation on his part such that non-astronomers (i.e. virtually everyone) can understand. Fess up Dimitar, you said what you said.

Keith's 28 Jul 10:54 am EDT update: It is rather odd that NASA Kepler and NASA PAO are shy about alerting the media to the presence Sasselov's comments (both short and long versions). No media advisory, press release, or email update have been issued. This is especially odd given the effect that his initial comments had and how the media portrayed them. Its almost as if the Kepler folks do not care to correct the record - thus letting stand the original interpretation by the media. Once again - remedial PR training for the Kepler team is long over due.

Two weeks ago I gave a talk at TED Global 2010 which was very well received, but caused confusion. I referred to past results from the NASA Kepler mission. Indeed, Kepler has not discovered Earth-like planets in habitable zones. We have not found Earth-size planets; at this time we have found only planet candidates - 706 of them as of June 15, 2010, based on only 43 days of data with 306 released and discussed in a paper by the Kepler team. Planet candidates are just that: "candidates". A sizable fraction will turn out not to be planets, and we do not know what that fraction is yet.

So that was my challenge - Kepler measures planet sizes, while I wanted to talk about geochemistry. In just 18 minutes. So, the expected number of planets, size and Earth-like chemistry got confused, and created a misunderstanding.

The family of our Solar System planets seems simple when sorted by size: half of the planets are large (giants) and half of the planets are small (terrestrial). The giants contain a lot of light gases (hydrogen and helium) in their bulk composition while the terrestrial ones contain mostly heavier elements. Too much hydrogen and helium dilute the surface chemistry, while heavy elements and solid surfaces tend to concentrate it. There is one planet in our Solar System where the chemistry has evolved to biochemistry and to a biosphere. In the search for life beyond Earth, the smaller planets are thus the favorite places to look.

The Kepler mission is designed to discover Earth-size planets by detecting and measuring their transits. The Kepler team collects additional information as it works to confirm a planet discovery, but one essential physical parameter Kepler provides is SIZE, the planetary radius. However, is "Earth-size" the same as "Earth-like"? And vice versa?

Kepler is capable of finding Earth-size planets in orbits of moderate temperatures. But most people consider the term “Earth-like” to mean that the planet has an atmosphere, liquid water on its surface, and a temperature conducive to life. In other words, "Earth-like" is often used to mean 'habitable'. Therefore, Earth-size and Earth-like are certainly not the same. Take the example of Venus, an Earth-size planet whose surface will melt lead.

The term "Earth-like" planet creates confusion. To some scientists like me, who model planet interiors, the term "Earth-like" is a simple short-hand for a bulk composition like Earth's. It emphasizes the broad difference between gas giants and terrestrial planets, as seen in our Solar System. However, I understand that this is not how it was interpreted by the majority of the media coverage. My definition allows for a whole range of planet sizes to be "Earth-like" planets. Thus, the question - what size planets might be "Earth-like"?, is more interesting. According to my definition, it involves the so-called "super-Earths" - planets larger in size and mass than the Earth, yet smaller than the giant planets. Many super-Earths are expected to have the same properties and potential for life as habitable Earth-size planets.

Kepler planetary candidates, like the 306 released this past June 15th, have estimated orbits and sizes. Sorted by apparent size, the majority of the candidates are found to be Neptune-size and smaller. This is the good news. As of today none of the candidates smaller than 2 Earth radii is in the habitable zone; their orbits are too small, which is why it was easier to spot them after just 43 days. Habitable planets will take a lot more time, as Kepler needs to observe more than one transit.

The first data release is an encouraging first step along the road to Kepler's ultimate goals, specifically, to determine the frequency of Earth-size planets in and near the habitable zone. However, these are candidates, not systems that have been verified sufficiently to be considered as planets. The distribution of planet sizes may also change. It will take more years of hard work to get to our goal, but we can do it.

The TED Global conference is about ideas worth spreading to a general audience. In my TED talk I decided to discuss the idea that science seems to be at the threshold of a new revolution - of synthetic biology. Ironically, this is happening at the completion of the previous, Copernican, revolution. My point was that the two events are related, and that, tantalizingly, progress in synthetic biology may be accelerated by input from planetary science. This is the core of the project I lead and we call the Origins of Life Initiative (not associated with the Kepler Mission).

The Origins of Life Initiative makes connections between geochemistry and biochemistry. The Kepler mission helps our project by establishing feasibility: if solid planets are common, then we have a shot at trying our lab experiments. This works as long as the planets have geochemical cycles that determine their atmospheric signatures. Hence, planets somewhat larger than Earth are more favorable (Sasselov & Valencia, Sci. American, Aug 2010). The Drake equation gives us an estimate of about 100 million such planets with habitable potential in the Milky Way galaxy. Kepler has not yet weighed in on this yet, but holds the potential to do so in the future.

• Dimitar Sasselov: How we found hundreds of Earth-like planets
  TEDGlobal Lecture
  
  Characteristics of Kepler Planetary Candidates Based on the First Data Set: The Majority are Found to be Neptune-Size and Smaller
  Borucki, W. and the Kepler Team, submitted to Astrophysical Journal
  
  Claims of 100 Earth-Like Planets Not True
  by Clara Moskowitz @ SPACE.com
  
  Millions of Earths? Talk causes a stir
  Cosmic Log on MSNBC.com by Alan Boyle

One of the scientists who works on the Kepler planet-hunting mission, Dimitar Sasselov, inadvertently set off a bit of a controversy when he appeared to announce that its first big data release implied that our galaxy is rich in Earth-like planets, with approximately 100 million habitable ones. That might be great news, except for some awkward facts: he dropped the news during an informal TED talk, and nobody at NASA or elsewhere was prepared to back up his assertions. In fact, the Kepler team has faced a bit of a backlash for its decision to limit the release of data on Earth-like candidates. Had Sasselov spilled the beans?

If you look at the video carefully, however, it's clear that Sasselov was making the same sorts of arguments that appear in one of the Kepler papers. Because of our methods of detection, our collection of exoplanets was biased towards massive gas giants; the distribution of planetary candidates found by Kepler implies that smaller, rockier planets are far more common when you perform an unbiased search. And that, as Sasselov noted, allows you to make some statistical inferences.

For example, Kepler has only been doing observations long enough to spot exoplanets orbiting close to the host star, but you can infer the distribution of sizes seen in those applies further out from the star and into the habitable zone. You can also assume the portion of the galaxy being imaged is typical of the galaxy as a whole. Put those together, and you apparently get the 100 million figure mentioned in the talk.

Given that the talk wound up receiving significant coverage in the press, NASA also convinced Sasselov to post a clarification on the Kepler blog. In it, he helpfully points out that he was using a very liberal definition of "habitable" in his talk. There's a big difference between Earth-sized and Earth-like. Even then, by a lot of criteria, Venus is pretty Earth-like, but has a surface temperature that can melt lead.

In the end, there seems to be little here that couldn't have been inferred from papers that are already posted on the arXiv. The news itself was mostly in the eye-popping 100 million habitable planets figure, but that clearly relies on making some very significant assumptions. Unfortunately, it's probably safe to assume that more people read the initial press coverage of Sasselov's talk than will read his clarification.

Kepler Mission - Errare Humanum Est, Natalie Batalha Kepler Co-Investigator, Beyond The Cradle

"Should NASA screen everything that the team plans to say in public? Should we, the Kepler team, screen everything our colleagues plan to say in public? I think that the best we can do is ask our colleagues for advice to make sure that we are understood. Perhaps that would have helped Dimitar. There are articles out there that say he shouldn't be allowed to speak in public. Yes, you heard me correctly -- that he shouldn't be allowed to speak. Rubbish. I can only say that I will take this PR blunder any day of the week over a work environment that does not give me academic freedom to speak within the reasonable agreements that I have with my colleagues. Any day."

Keith's note: Let me be clear, does Ditimar Sasselov have the right to speak his mind in public about his research? Of course he does. Does Sasselov have a professional responsibility as the Co-Investigator on an enormously expensive, taxpayer-funded NASA mission to get his facts straight before he speaks? Of course he does. Does he (and the rest of his team) need to be internally and externally consistent when it comes to the rationale for what they do or do not want to release, how they release it, and where they release it? Of course they do.

Perhaps most importantly, do the people who are chosen to speak publicly (and those who decide to speak publicly on their own) about these enormously important research projects need to understand how to communicate their jargon-filled, complex ideas to the public at large? Of course they do. Bad communication is often worse than no communication at all.

Millions of people stopped what they were doing to read these stories about "Earth-like planets" circling other suns. Such words have meaning. 99.999% of humans don't dwell on the nature of planetary cores and the other excuses offered in support of the use of the term "Earth-like" in this lecture. We live on Earth. This guy said there are worlds out there "like Earth". Lots of them. When most people hear the words "Earth-like" they look out the window at Earth. The don't run to grab a textbook or Google some planetary geology website.

This is paradigm shifting stuff. Its about confirmation of centuries of speculation and dreaming as to the nature of our world's uniqueness and/or commonness with regard to the universe around us. Now the Kepler team is fumbling its way through clarification of what was said and was not said, implied and miscommunicated.

Instead of channeling the eventual (and apparently inevitable if the statistics are to be believed) incredible news in a way that could really show the world what is waiting out there for us, back peddling and PR spinning is now what we hear. We should be cheering in the streets. As far as small little rocky worlds go, we are not alone. How profound is that !? Alas, when the news is eventually released, as everyone seems to think it will be, there will be a caveat tossed in - people will wonder if this is the real thing or yet another false alarm. Leave it to NASA scientists to screw up a good thing like this.

If you are going to go out and talk about things with such an epochal potential for all humans to think about, you owe it to everyone involved (in other words everyone, everywhere) to make damn sure you know how to convey this information. If not, then find someone who can do it.

We could certainly use Carl Sagan right now.

Nature - and the news media, it seems - abhors a vacuum. That could explain the recent uproar over a talk by Dimitar Sasselov, a member of the planet-hunting Kepler space telescope's science team.

Kepler launched in March 2009 and has been hard at work staring at the same patch of sky in search of characteristic dips in starlight that would signal a passing planet. Progress has been fairly quick. Not long after reaching orbit, the telescope team released the vital stats on five confirmed planets and announced it had found 706 stars that seem to have planet potential.

But NASA has allowed data on 400 of these stars, which include the brightest and easiest to study, to be held back from public release until February 2011. This secrecy has frustrated some astronomers and fueled a hunger for news of more planets, particularly Earth-like ones.

Enter Sasselov, who presented a talk at a TEDGlobal conference in Oxford on 16 July. In his presentation, Sasselov presents a chart (shown above) that suggests Kepler has found about 140 "Earth-like" candidates smaller than two times the radius of the Earth.

That figure is baffling, because it conflicts with the official Kepler results, which turned up just 38 such Earth-sized candidates in the 306 stars that were made public in June.

The talk was quickly picked up by the press and presented as a new discovery. It also took on an air of scandal. Richard Kerr of Science magazine dubbed the presentation a leak. The talk, he said, "was especially striking because it was largely based on Kepler data that team members had been allowed to keep to themselves for further analysis until next February."

Not so, says Sasselov. He says his chart uses the same data that was presented in Kepler's previous announcement, only it has been "rebinned" to include candidates with larger radii, up to 2.9 times the radius of the Earth. The chart label fell victim to TED font size requirements, and the "9" was lopped off instead of being rounded up. "The chart definitely has a mistake," Sasselov told New Scientist.

The larger planet candidates were lumped together with smaller ones to reflect the notion that they are all rocky bodies that could have the potential to harbour life.

But finding such planets in the habitable zones of their stars is still a ways off. None of the small planet candidates that have been reported so far, which come from just 43 days of Kepler data, orbit far enough from their hosts to be habitable.

As a result, none of the 140 or so "Earth-like" planets presented in Sasselov's talk are likely to be pleasant vacation spots.

"The term 'Earth-like' planet creates confusion. To some scientists like me, who model planet interiors, the term 'Earth-like' is a simple short-hand for a bulk composition like Earth's," Sasselov wrote in a blog post on NASA's web site.

"But most people consider the term 'Earth-like' to mean that the planet has an atmosphere, liquid water on its surface, and a temperature conducive to life. In other words, 'Earth-like' is often used to mean 'habitable'," he continued. "Therefore, Earth-size and Earth-like are certainly not the same. Take the example of Venus, an Earth-size planet whose surface will melt lead."

We may not have found them yet, but astronomers do expect to find a number of planets with cosy, Earth-like properties. Hunts for periodic shifts in the spectrum of starlight - which can reveal wobbles due to tugging planets - have shown that planets with radii up to a few times that of Earth are common very close to their stars, where it's too hot for life as we know it to survive. "Because we find a lot of planets on short-period orbits, we expect to find a lot of planets on long-period orbits," says Greg Laughlin of the University of California, Santa Cruz. "It would be extremely surprising if Earth-like planets in the habitable zone were rare."

There may very well be hundreds of millions of potentially habitable rocky planets in the Milky Way, but solid estimates are still a ways off.

The race to find the very first one could well be won by teams looking for wobbling stars rather than dips in starlight, Laughlin says. That's because surveys that look for these wobbles are better suited than Kepler to find planets around small, dim stars. Habitable planets around these puny stars would be on tighter, faster orbits than those around larger stars, making them relatively easy to spot.

The following NASA statement was sent to Dr. S. Pete Worden, Director, NASA Ames Research Center from the Kepler Science Council on Aug. 2, 2010.

"Recently there have been reports to the effect that Kepler has discovered many Earth-like planets. This is not the case. Analysis of the current Kepler data does not support the assertion that Kepler has found any Earth-like planets.

Kepler is producing excellent results and is on a path to achieving all its mission requirements and actually determining the frequency of Earth-size planets, especially in habitable zones. We will announce our results when they become available and are confirmed."

Signed,

Edward W. Dunham, Kepler Science Team Lead
Thomas N. Gautier, Kepler Project Scientist
William J. Borucki, Kepler Principal Investigator

for the Kepler Science Council

NASA will hold a media teleconference Thursday, Aug. 26, at 1 p.m. EDT to discuss the Kepler spacecraft's latest discovery about an intriguing planetary system.

Kepler, a space observatory, looks for the data signatures of planets by measuring tiny decreases in the brightness of stars when planets cross in front of, or transit, them. In June, mission scientists announced the mission has identified more than 700 planet candidates, including five candidate systems that appear to have more than one transiting planet.
...
Audio of the teleconference will be streamed live at: http://www.nasa.gov/newsaudio

Artist's concept: Two Saturn-sized planets discovered by NASA's Kepler. The star system is oriented edge-on, as seen by Kepler, such that both planets cross in front of, or transit, their star (Kepler-9). This is the first star system found to have multiple transiting planets. [i](Credit: NASA/Ames/JPL-Caltech)[/i]

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NASA's Kepler Mission has discovered the first confirmed planetary system with more than one planet transiting the same star.

Today's announcement of the discovery of the two planets, Kepler 9b and 9c, is based on seven months of observations of more than 156,000 stars being monitored for subtle brightness changes as part of an ongoing search for Earth-like planets outside our solar system. Scientists designated the sun-like star Kepler-9.

The inner world, Kepler 9-b, orbits its star every 19.2 days at a distance of 13 million miles, while the outer world orbits once in 38.9 days at a distance of 21 million miles. (In comparison, Mercury has an orbital period of 88 days.) They orbit nearly in resonance, with the inner planet completing two orbits for every one of the outer planet. Both are Saturn-sized gas giants, with the inner world weighing in at 0.25 Jupiter mass (80 Earths) while the outer world is a slimmer 0.17 Jupiter mass (54 Earths).
...
In addition to the two confirmed giant planets, Kepler scientists also identified an additional "super-Earth-size" transiting planet candidate that will need additional observations to confirm if it is indeed a planet or merely a false alarm. Current observations suggest that the planetary candidate might be about 1.5 times the size of Earth and orbits the star once every 1.6 days at a distance of only 2.5 million miles.

Click to view full size image

The Kepler mission has discovered a system of two Saturn size planets with perhaps a third planet that is only 1.5 times the radius of Earth. While the news of this discovery is tempered somewhat with the announcement by a team from the European Southern Observatory of a system with five confirmed Neptune-sized planets and perhaps two additional smaller planets, both discoveries highlight that the spacecraft and techniques astronomers are using to find exoplanets are getting the desired results, and excitingly exoplanet reseach now includes the study of multiplanet systems. This discovery is the first time multiple planets were found by looking at transit time variations, which can provide more information about planets, such as their masses.

“What is particularly special about this system, is that the variations in transit times are large enough, that we can use these transit timing to detect the masses of these bodies” said Matthew Holman, Kepler team lead for the study of star Kepler-9, speaking on the AAAS Science podcast. Additionally, these findings should provide the tools astronomers need to determine even more physical conditions of these planets — and others — in the future.

Somewhere around 2000 light years away in the direction of the constellation Lyra is a Sun-like star orbited by at least two Saturn-class planets. What’s interesting about this news, as just discussed in the Kepler press conference I’ve been listening to this afternoon, is that for the first time we’ve detected and confirmed more than one planet around a single star using the transit method. But much more important, transit timing variations — the leads and lags of the two planets as they transit the star as seen from Kepler — can be used to tease out new and significant information.

Kepler-9b and 9c mark the first clear detection of transit timing variations by Kepler, allowing us to study the gravitational interactions between the planets involved. And that’s useful stuff: We see two planets in a 2:1 orbital resonance, one with a 19.2-day orbit, the other with a 38.9-day orbit. As the inner planet completes two orbits, the outer planet completes one. The variations in transit time (TTV) help us establish the mass of the two planets, showing that both have a mass and radius slightly smaller than Saturn. Peg size and mass and you can derive planetary density.

We’ve known for some time that transit timing variations should be a useful part of the exoplanet toolbox, but seeing them working in practice is a powerful proof of concept. The hope, of course, is that similar TTV methods can be put to work on smaller worlds down to terrestrial mass planets in the habitable zones of their stars. In fact, in this case, the Kepler 9 system sports a candidate that is 1.5 times the radius of Earth, a possible super-Earth whose barely detectable signature is not yet sufficient for us to declare the planet confirmed.

The other aspect of the Kepler 9 system that received discussion at the news conference was what it can tell us about planetary formation theories. These planets orbit well within the orbit of Mercury in our own system, and the assumption is that they could not have formed there. Planetary migration resulting in a 2:1 orbital resonance is something that points back to an earlier set of conditions whose nature will take many more precision measurements — in this and many other systems — to understand. But ultimately, the way a planetary system looks today can reveal much about its history.

NASA came under criticism in June when it announced that its space-based telescope Kepler had detected 706 potential new exoplanets, but only released data for 306 of the candidate planets. To rule out “false alarms” from bona fide exoplanet discoveries, Kepler's scientific team wanted to give themselves time to do follow-up observations on the most promising targets. But it turns out that we didn’t have to wait too long. Today, researchers have announced two confirmed Saturn-sized planets from Kepler’s “top 400.”

The new telescope has also made the first concrete observation of a gravitational tug-of-war between neighboring exoplanets, which will allow astronomers to pinpoint the bodies’ masses in unprecedented detail, and probe how these alien solar systems formed and evolved.

The Kepler telescope, launched in March 2009, detects exoplanets by looking for a periodic dimming in stellar brightness, caused by a planet transiting (passing in front of) a star. Previously, astronomers relied on follow-up radial velocity observations, which look for the degree to which the gravitational pull of the planet perturbs the star that it orbits, to determine the masses of such planets. Such measurements have a lot of uncertainty, however, as they depend on the inclination of the planet’s orbit, which isn’t well known.

But if two exoplanets orbiting the same star have a strong gravitational influence on each other, the time of transit is not periodic, and astronomers can use this information to more accurately calculate their masses.

In a paper published online today in Science Express, Kepler researchers announce the first definitive observation of such transit time variations in planets called Kepler-9b and 9c. Combining Kepler’s initial transit observations with traditional radial velocity measurements, the scientists have been able to calculate that the two planets are just slightly less massive than Saturn. Additional observations in the years ahead should ultimately give much more accurate masses. “We will know the masses [of these planets] better than any planet outside of our Solar System,” says lead author Matthew Holman from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. Holman says the changes in the transit times of these planets were enhanced by the fact that one of the planets orbits the star in almost exactly half of the time that it takes the other, as such ‘orbital resonances’ increase their gravitational interaction.

Astronomer David Nesvorny from the Southwest Research Institute in Boulder, Colorado, who was not involved in the study, calls the detection of transit time variations “solid” and believes it’s the beginning of many important discoveries to come from the Kepler mission. “Gravitational interaction of planets in our solar system is central to our understanding of its formation and evolution, yet this interaction had been elusive in exoplanet systems,” Nesvorny says. Kepler will probably obtain similar data on hundreds of other solar systems, he says, which could then be characterized to an unprecedented detail. "This could be a true revolution.”

• Science Express (online 26 Aug 2010) DOI: 10.1126/science.1195778

orin stepanek wrote: Part of the 750; I imagine.