Where New Horizons is

[bystander]

Pluto: A Dwarf Planet Oddity (Infographic)
Space.com | Karl Tate | 2011 July 20

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[bystander]

Remind Me Again, Why Isn't Pluto a Planet?
Discovery News | Mark Thompson | 2011 July 26

In light of the discovery of a fourth moon orbiting Pluto, Mark Thompson ponders what it takes to be called a "planet."

Artist impression of Pluto and largest moon Charon from the surface of either Nix or Hydra, two smaller moons. [i](Credit: NASA)[/i]

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Last week, news broke that a team of astronomers using the Hubble Space Telescope had discovered a new moon in orbit around Pluto.

They were actually looking for signs of a ring system when they stumbled across another tiny object -- now imaginatively called "P4" -- bringing Pluto's moon count to four.

This is quite a nice little news story in its own right, and covered by my Discovery News colleague Irene Klotz. However, what I hadn't anticipated was a deluge of messages asking me if this means Pluto is now a planet again.

Well, the answer is a resounding no. It is still, and always will be, a dwarf planet.

But what rules have we applied to Pluto to forever condemn it to the back seats of the solar system rankings?

Before we look at the well established rules of planetary terminology, it's worth remembering why we even need such a definition.

Like many of you, I was taught as a school kid that there were nine planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto along with thousands and thousands of tiny objects called asteroids. For a long time, Pluto was believed to larger than Mercury but after the discovery of Charon (Pluto's largest moon) in 1978, the foundations of its planetary status started to wobble.

By studying Charon, astronomers could accurately determine the mass of Pluto and surprisingly found it to be much smaller than Mercury and even our own moon.

During the late 20th century, more objects started to be discovered at comparable distances to Pluto's orbit and beyond; one of which, Eris, was even thought to be larger than the ninth planet in our solar system. Eris was discovered by Mike Brown and his Palomar Observatory-based team in 2005.

These discoveries led the International Astronomical Union (IAU) to setup a committee in 2005 to consider an official definition of a planet. There were a number of different definitions that were considered, but in 2006 a final, all-encompassing set of criteria was identified that, once and for all, knocked Pluto off its planetary pedestal.

For a celestial body to be considered a planet, it must;

1) be in orbit around the sun.

Clearly, Pluto is in orbit around the sun, but so do thousands of asteroids. As far as this criterion is concerned, Pluto is still hanging on by the skin of its teeth.

2) have sufficient mass to assume hydrostatic equilibrium.

This is just a posh way to say it is pretty much spherical in shape. Note the careful use of the phrase 'pretty much'; no planet is a perfect sphere. Due to their rotation, often they are a little squashed along the polar axis.

This criterion is just saying they that they must have sufficient gravity to have overcome other forces and mould a more-or-less sphere-shaped body. Pluto maintains hydrostatic equilibrium, whereas many of the asteroids and other minor planets are quite oddly shaped.

3) have cleared the neighborhood around its orbit.

BOOM! That's the nail in the coffin for Pluto.

This final criterion requires that it must have cleared its orbit of all other objects of comparable size, other than its own satellites. This means "a planet" must be gravitationally dominant in its orbit and this is where Pluto fails. Pluto not only shares its orbit with a number of other Kuiper Belt objects, but it also flies inside the orbit of ice giant Neptune!

The small print here says that if it fails on this point alone, then it must be classified as a dwarf planet. And so the case against Pluto finally got laid to rest in 2006 when the IAU voted to "demote" Pluto to the status of dwarf planet.

The recent discovery of another moon in orbit around the tiny distant world doesn't change anything, sadly.

I think in the hearts of thousands of people, Pluto will still always be the ninth planet in our solar system; we just won't talk about it (much).

[orin stepanek]

3) have cleared the neighborhood around its orbit.

BOOM! That's the nail in the coffin for Pluto.

Trouble is that this rule was made up solely to kick Pluto out of planetary status to please certain IAU members. I Vote Pluto to be a Planet in good standing along with other planets discovered recently.
Go New Horizons

[Beyond]

Maybe we should just call a planet, a planet, when it has some kind of life on it. Some how i just don't quite get along with calling uninhabitable rocks and gas balls, planets. So that would make earth the ONLY planet in this solar system. Simple enough?

[orin stepanek]

Maybe we should just call a planet, a planet, when it has some kind of life on it. Some how i just don't quite get along with calling uninhabitable rocks and gas balls, planets. So that would make earth the ONLY planet in this solar system. Simple enough?

Awh; we all know that the Earth is very special. The rocks and gas balls are still planets though. Besides' the Earth didn't always have life on it; and Mars may have at one time. And what if life was seeded by comets? http://www.upi.com/Science_News/2010/09 ... 284485211/

[Beyond]

And what if life was seeded by comets?

Oh-good! Something to blame

[orin stepanek]

I don't know how much power New Horizons has to use up; but, wouldn't it be nice if it would take a picture of Pluto once a month so we could watch from way out till it approached Pluto and it's moons!

[neufer]

[b][color=#0000FF]Dawn's First Glimpse of Vesta (~2300 Vesta diameters) away[/color][/b]

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I don't know how much power New Horizons has to use up; but, wouldn't it be nice if it would take a picture of Pluto once a month so we could watch from way out till it approached Pluto and it's moons!

Just one month before Pluto flyby New Horizons will still be ~15,600 Pluto diameters (~36 million kilometers) away.

We didn't get a good view of Vesta from the Dawn spacecraft until it was only ~2300 Vesta diameters away.

<<This image, processed to show its true size, shows Vesta in front of a spectacular background of stars. It was obtained by the framing camera aboard NASA's Dawn spacecraft on May 3, 2011, from a distance of about 1.2 million kilometers (~2300 Vesta diameters). Since Vesta is so bright that it outshines its starry background, Dawn team members commanded a long exposure time to make the stars visible. They corrected the resulting exaggerated size of Vesta by superimposing a short exposure image of the target asteroid, showing its true size. Vesta is the small, bright pearl in the middle of the image.>>

[orin stepanek]

What will Pluto look like! Here is an artists picture.

Click to view full size image

[neufer]

What will Pluto look like! Here is an artists picture.

Given a maximum Surface temperature of just 55K it looks a tad warm.

How about

Artist impression of the surface of Pluto. Credit: ESO/L. Calçada

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[brightside]

This month marks a warm up spell for the New Horizons spacecraft currently on its way to Pluto. Launched January 19th 2006, this mission is now covering a million kilometres a day as it heads to the Pluto system for a rendezvous in July 2015.

The discovery last summer of yet another moon of Pluto has the science team a mite worried –not so much about the new moon- referred to as Pluto IV, but about a possible debris cloud around the whole system. When the spacecraft reaches Pluto it will be zipping along at a flyby speed of 14 kilometres-per-second. At that rate, even particles less than a milligram can penetrate the micrometeoroid blankets and do a lot of damage to electronics, fuel lines and sensors. Continue http://beforeitsnews.com/story/1651/936 ... Pluto.html

[neufer]

The discovery last summer of yet another moon of Pluto has the science team a mite worried –not so much about the new moon- referred to as Pluto IV, but about a possible debris cloud around the whole system. When the spacecraft reaches Pluto it will be zipping along at a flyby speed of 14 kilometres-per-second. At that rate, even particles less than a milligram can penetrate the micrometeoroid blankets and do a lot of damage to electronics, fuel lines and sensors. Continue http://beforeitsnews.com/story/1651/936 ... Pluto.html

[size=150][color=#0000FF]Letter head from Half Way to Hell Club.[/color][/size]

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<<The Half Way to Hell Club was an exclusive club organized by the men who fell from the Golden Gate Bridge in 1936 and 1937 and were saved by the safety nets [i.e., blankets]. Iron Worker Al Zampa (1905–2000), as one of the club's first members and the last surviving member, became the unofficial spokesman for the club. According to Zampa when a man fell to his death from a bridge it was said "he's gone to hell." The men who fell and were saved by the nets were said to have fallen only "half way to hell." Zampa goes on: "There were ten of us that fell into the nets those first few weeks. Four got hurt. I was one of them. We were in the hospital together. We formed the club right there in St. Luke's Hospital."

Photographer and bridge historian John V. Robinson writes in his book that no one is really sure what became of the 19 men who fell into the nets. No complete list of names has ever been discovered. But, Al Zampa who lived to age 95 may have been the last surviving member of the club.>>

[bystander]

New Horizons Aims to Put Its Stamp on History
NASA | JHU-APL | New Horizons | 2012 Feb 01

[i]New Horizons stamp concept by Dan Durda.[/i]

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New Horizons’ flight to explore the Pluto system in July 2015 will be a historic accomplishment for the U.S. space program, for planetary science, and indeed for all humankind.

Plans for the flyby are well under way – and now, so is an effort to petition the U.S. Postal Service to commemorate the historic achievements of New Horizons on a stamp. The mission team launches that petition today, in early 2012, and plans to submit the petitioners’ names and a formal proposal to the U.S. post office knowing it often takes three years or longer for a proposal to result in an actual stamp.

“You can help make this happen,” says New Horizons Principal Investigator Alan Stern. “We’re asking people to sign the petition, because the post office considers not just the merits of a new stamp proposal, but also whether it is supported by a significant number of people. This is a chance for us all to celebrate what American space exploration can achieve though hard work, technical excellence, the spirit of scientific inquiry, and the uniquely human drive to explore.”

The Southwest Research Institute’s Dan Durda, a space scientist and artist whose works appear on the New Horizons website and many other venues, has designed a concept for a new Pluto stamp – which would be the successor to the 1990 U.S. postage stamp that labeled Pluto as “Not Yet Explored.”

You can help by signing the petition urging the post office’s Citizen Stamp Advisory Committee to recommend a New Horizons stamp to the postmaster general. Tell your family members, Facebook friends and Twitter followers to sign as well!

New Horizons US Postal Service Stamp Petition

Give Pluto your stamp of approval
Discover Blogs | Bad Astronomy | 2012 Feb 01

Help Support a ‘New Horizons’ U.S. Postage Stamp!
Universe Today | Ray Sanders | 2012 Feb 01

[geckzilla]

Signed!

[Chris Peterson]

Plans for the flyby are well under way – and now, so is an effort to petition the U.S. Postal Service to commemorate the historic achievements of New Horizons on a stamp. The mission team launches that petition today, in early 2012, and plans to submit the petitioners’ names and a formal proposal to the U.S. post office knowing it often takes three years or longer for a proposal to result in an actual stamp.

I hope they can approve a concept stamp but still allow it to change. In the final stamp, Pluto and Charon should be shown as they actually appear, not so much of the "artist concept" view. Because always, without exception, these images look instantly dated once we have real, high resolution imagery.

[orin stepanek]

I signed it!

[neufer]

.

I hope they can approve a concept stamp but still allow it to change. In the final stamp, Pluto and Charon should be shown as they actually appear, not so much of the "artist concept" view. Because always, without exception, these images look instantly dated once we have real, high resolution imagery.

[orin stepanek]

Today 2/12/12 New Horizons is less than 10 au from Pluto encounter.

[bystander]

Spacecraft Sprints to Within a Billion Miles of Pluto
Discovery News | Ray Villard | 2012 Feb 13

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On Feb. 10, NASA's Pluto-bound New Horizons probe entered the homestretch of its mission.

When you are sprinting across the solar system, "homestretch" is the final 1 billion miles of your journey. That sounds like quite a stretch, but the half-ton spacecraft has already logged 2 billion miles since its launch in early 2006. That’s twice the distance between Earth and Saturn.

Though the spacecraft is still three years away from its Plutonian close encounter, mission scientists call this the Late Cruise phase of the flight.

...

At the spacecraft’s present distance, much of the solar system fits within a panoramic field of view.

The sun is reduced to a bright dot seen against the backdrop of constellations, midway between Gemini and Orion. The sun is glowing at one four-hundredth its brightness as seen from Earth. The inner planets are clustered near the sun within an angular diameter equivalent to eight moon diameters. Jupiter appears as a bright star 10 degrees to the west of the sun. Saturn looks like another bright star 25 degrees to the east of the sun.

...

Images: NASA

[orin stepanek]

In less than 1200 days New Horizons will be in Pluto's vicinity! less than 3.29 years. I wish it were tomorrow!

[Céline Richard]

In less than 1200 days New Horizons will be in Pluto's vicinity! less than 3.29 years. I wish it were tomorrow!

It sounds astonishing, incredible, that New Horizons goes so far away

[orin stepanek]

Time wise New Horizons has now completed 2/3's of it's journey to rondevu with Pluto!

[saturno2]

Hi Orin stepanek
Where New Horizons is ( today 11 - june - 2012 ) and
What is the speed now?
Thanks

[bystander]

Where New Horizons is ( today 11 - june - 2012 )

http://pluto.jhuapl.edu/mission/whereis_nh.php

[saturno2]

Thanks, Bystander