APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

[APOD Robot]

Kepler 78b: Earth Sized Planet Discovered

Explanation: Even though Kepler-78b is only slightly larger than the Earth, it should not exist. Its size is extraordinary only in the sense that it is the most similar in size to the Earth of any exoplanet yet directly discovered. Its orbit, however, is extraordinary in the sense that it circles a Sun-like star 40 times closer than planet Mercury. At such a scathing distance, even rock is liquid. Models of planet formation predict that no planet can form in such a close orbit, and models of planet evolution predict that Kepler-78b's orbit should decay -- dooming the planet to eventually merge with its parent star. Illustrated above in comparison with the Earth, Kepler-78b was discovered by eclipse with the Earth-trailing Kepler spacecraft and further monitored for subtle wobbles by the HARPS- North, a spectrograph attached to the 3.6-meter Telescopio Nazionale Galileo in the Canary Islands.

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[bystander]

Scientists Discover the First Earth-size Rocky Planet
NASA | JPL-Caltech | Ames Research Center | Kepler | 2013 Oct 30

Scientists Find Earth-Sized Rocky Exoplanet
University of Hawaii | Institute for Astronomy | 2013 Oct 30

Mystery World Baffles Astronomers
Harvard Smithsonian Center for Astrophysics | 2013 Oct 30

[1Al]

the underlying problem is one; belief that in the universe the earth is the ideal place for life, but it is not. More likely life should be sought on planets with tight orbits around red and brown dwarf stars . Of course, many of these planets would not even be detected optically being immersed in the outer layers of the stellar atmospheres.
it is the solar system most likely to be an anomaly.

[starsurfer]

Maybe Kepler 78b formed at a distance from its star and then its orbit became closer somehow?

[Boomer12k]

I am wondering if it formed much farther out...like at Venus's orbit, or so....and then it was slowed down or hit by another object ...
and then has been moving closer and closer....


:---[===] *

[RedFishBlueFish]

One in Five? At least of sun-like stars. Remarkable.

Any estimate of how many of these will have a Garden of Eden?

[geckzilla]

the underlying problem is one; belief that in the universe the earth is the ideal place for life, but it is not. More likely life should be sought on planets with tight orbits around red and brown dwarf stars . Of course, many of these planets would not even be detected optically being immersed in the outer layers of the stellar atmospheres.
it is the solar system most likely to be an anomaly.

Until we have observed life on other planets there's no way we can say what's ideal. Earth is our only example and it makes sense for now to use it. That said, I think exobiologists are extremely imaginative and have taken a lot of ideas into consideration. It must be very frustrating knowing we'll most likely never get to study an alien animal of any kind in our lifetimes.

[BDanielMayfield]

One in Five? At least of sun-like stars. Remarkable.

I agree. This gives much hope for finding more life elsewhere, but ...

Any estimate of how many of these will have a Garden of Eden?

As used in the exoplanet field, the expression habitable zone can be somewhat misleading, if its definition isn’t understood. In common usage the word habitable can have a homey, comfortable connotation, but that is not what astronomers mean when they use the word. It certainly doesn’t mean that a planet in the HZ is going to necessarily be hospitable for human colonization, for example. In the exoplanet setting the word habitable means that the proximity to a planet’s star is such that a planet might have temperatures permitting liquid water to exist. This includes many boiling and freezing planets that we would find very uninhabitable.

[rstevenson]

It would have been helpful to have distance from earth in this description. How far away is it?

I agree, but it looks like we don't know. I checked the Extrasolar Planet Database online and the distance to Kepler 78 is not given.

Who says that our planetary origin and planetary evolution models are correct. They're just models based on our observations to date. Twenty years from now they won't resemble what the are today.

Science is not a book of answers; it's a process of learning. Of course, 20 years from now we'll know more about how our planet was created and how it evolved, but we are extremely unlikely to find out something so astounding that it blows away our current theories in the way you suggest. Scientific understanding increases incrementally, not through explosive revelation.

Rob

[neufer]

---

It would have been helpful to have distance from earth in this description. How far away is it?

I agree, but it looks like we don't know. I checked the Extrasolar Planet Database online and the distance to Kepler 78 is not given.

Kepler was zeroed in on the Orion Spur of the Milky Way about 2300 light years away (past the North America Nebula at 1600 light years).

[robgendler]

Because of what I do I have one foot in the astronomical sciences and one in the biological sciences. Its very curious that the only scientists who are enthusiastic and optimistic about extraterrestrial life are physical scientists (astronomers, physicists, mathematicians, statisticians). Almost without exception because of their backgrounds they view all science in a deterministic manner...believing everything can be predicted with the right equation. Unfortunately biological systems defy deterministic approaches. Evolution proceeds in a manner which is not in any way deterministic....the evolutionary process is an opportunistic one, shaped in a large part by chance and opportunism. The expectation that life is ubiquitous in the universe is a very naive one IMO. Perhaps simple life (prokaryotes) may be somewhat common...but complex multicellular life....and civilizations ....I'm not at all optimistic about that, Evolutionary biologists have a very deep respect for the improbability of complex life to form even here on earth. If one studies the history of life on earth it is impressive that after the first simple lifeforms...bacteria...nothing much happened for another 2.5 billion years...more than half the age of the earth. Complex life only occurred in the last 10% of earth's history. In fact in the course of 4.5 billion years over a trillion species have come and gone and only one species has evolved which eventually produced technology....and not until the last 1% of its existence as a species. This does not bode well for the expectation of extraterrestrial civilizations. The other interesting observation is that there exists two earth like planets (mars and venus) in our own solar system and each is totally devoid of life.

[carsten_nielsen]

I noticed that one of the Hot Jupiters is so close that it evaporates, the gasses are boiled off from it.

Of course the rocks are the last to be blown away.

Jupiter is supposed to have a rocky core.

I'm not so sure the Hot Jupiters formed further away from the star. When a star forms, the planetary disc forms right next to it, I understand.

Then the magnetic field is supposed to connect to it and move it outwards. If that fails you get a close binary star like 70 Uma.

Regards

Carsten Nielsen
Denmark

[Chris Peterson]

Who says that our planetary origin and planetary evolution models are correct. They're just models based on our observations to date.

This is an extremely foolish thing to say, typical of the scientifically illiterate.

"Just" models. "Just" theories. Nonsense. There is nothing "just" about them. Models and theories are what form our understanding of nature. They are powerful tools. In the era of modern science, it has been rare for entire theories to be replaced. As the quality of our understanding has grown, and our analytical tools have improved, so too has our knowledge of how things work. Yes, our theories of planetary origin and evolution will continue to develop. But it's extremely unlikely that they will look substantively different in the future, only richer.

[Donald Pelletier]

Kepler is orbiting around the Sun, not around the Earth : see FAQ http://kepler.nasa.gov/Mission/faq/ E3

[geckzilla]

Kepler is orbiting around the Sun, not around the Earth : see FAQ http://kepler.nasa.gov/Mission/faq/ E3

Thanks, I mailed RJN about it. "Earth-trailing" I'm sure was intended to be written but not what ended up being written.

[wsodonnell2]

An under-appreciated feature of APOD explanations is the high quality of the writing. They are clear, concise, thoughtful and polished: they maintain a high standard of journalistic craftsmanship.
However the word 'scathing' in this context is at best dubious. It has aroused my inner pedant. Perhaps 'scalding' or 'scorching' would have been a better choice?

in gratitude for all you do,
--- WSOD

[Ann]

Thank you for your input, Rob Gendler!

I have made myself known as a skeptic when it comes to life in space. That doesn't mean that I consider the rest of the universe to be lifeless, because how could I possibly know such a thing? To make such a claim with even a hint of certainty would be utter folly. Bear in mind, too, that if the rest of the universe is in fact lifeless, then we will never know it. We can only ever prove the actual existence of other life in the universe, but we can never prove the absence of it.

So when I say that I'm skeptical, I just mean that I don't understand the reason for the very great optimism about life in space on the part of many astronomers. Yes, I can see a reason for believing in a great prevalence of very simple life forms, but I don't understand how astronomers can use our human civilization as a reason to believe in hundreds of thousands or millions and millions of technological civilizations elsewhere. Yes, I realize that there may be hundreds of thousands or millions and millions of other technological civilizations, but I don't understand why we should strongly believe that technological civilizations are plentiful "out there".

Neufer recently explained why he believes that there are at least 265,000 stars with planets hosting intelligent life forms in the universe. Unfortunately his post didn't make much sense to me. Since I am a complete amateur it is no wonder if I don't understand the reasoning of professional astronomers, and it is of course impossible for me to make any sort of guess at how many planets with indigenous intelligent life forms there might be. Neufer's estimate may be perfectly correct for all I know, but what I don't understand is how he can be so sure.

Ann

[geckzilla]

To be fair, neufer is not a professional astronomer. Unless he's been hiding something from us for all this time. All that's needed to understand that post is a bit of math nerdery.

[RJN]

Kepler is orbiting around the Sun, not around the Earth : see FAQ http://kepler.nasa.gov/Mission/faq/ E3

Oops. And I think I've made this mistake before, too. Fixed it. Thanks! - RJN

[neufer]

An under-appreciated feature of APOD explanations is the high quality of the writing. They are clear, concise, thoughtful and polished: they maintain a high standard of journalistic craftsmanship. However the word 'scathing' in this context is at best dubious. It has aroused my inner pedant. Perhaps 'scalding' or 'scorching' would have been a better choice?

in gratitude for all you do, --- WSOD

Great mercy, sure! It seems an OK word to me:

Scath, n. [Icel. ska\'ebi; akin to Dan. skade, Sw. skada, D. schade, schaden.] Harm; damage; injury; hurt; waste; misfortune.

But she was somedeal deaf, and that was skathe. - Chaucer.

Great mercy, sure, for to enlarge a thrall, Whose freedom shall thee turn to greatest scath. - Spenser.

Wherein Rome hath done you any scath, Let him make treble satisfaction. - Shak.

[Guest]

Kepler 78b: Earth Sized Planet Discovered

Explanation: Even though Kepler-78b is only slightly larger than the Earth, it should not exist. Its size is extraordinary only in the sense that it is the most similar in size to the Earth of any exoplanet yet directly discovered. Its orbit, however, is extraordinary in the sense that it circles a Sun-like star 40 times closer than planet Mercury.

What does it mean to be forty times closer than planet Mercury? Perhaps I'm too old or stupid (or both), but my reading all too often seems to be disrupted by such questions. If, as I suspect, it means that its distance from its star is a fortieth of that from Mercury to ours, I wonder why it isn't reported so.

[neufer]

To be fair, neufer is not a professional astronomer. Unless he's been hiding something from us for all this time.

Neufer is a professional member of the physical scientists (astronomers, physicists, mathematicians) who after being forced to take 4 MIT humanity courses (all in literature) believes that he knows better than most professional literary historians about who Shakespeare was.

All that's needed to understand that post is a bit of math nerdery.

Neufer is also a published math nerd.

[geckzilla]

I just think of you as the weather guy, Art.

[Ann]

Kepler 78b: Earth Sized Planet Discovered

Explanation: Even though Kepler-78b is only slightly larger than the Earth, it should not exist. Its size is extraordinary only in the sense that it is the most similar in size to the Earth of any exoplanet yet directly discovered. Its orbit, however, is extraordinary in the sense that it circles a Sun-like star 40 times closer than planet Mercury.

What does it mean to be forty times closer than planet Mercury? Perhaps I'm too old or stupid (or both), but my reading all too often seems to be disrupted by such questions. If, as I suspect, it means that its distance from its star is a fortieth of that from Mercury to ours, I wonder why it isn't reported so.

I, too, prefer that way of putting it.

Ann

[neufer]

Click to play embedded YouTube video.

I just think of you as the weather guy, Art.

“Tonight’s forecast: Dark. Continued dark throughout most of the evening, with some widely-scattered light towards morning.” - Art Sleet