Vesta Is a Baby Planet, Not an Asteroid

astroengine writes "Vesta, the second largest object in the main asteroid belt, has an iron core, a varied surface, layers of rock and possibly a magnetic field — all signs of a planet in the making, not an asteroid (abstract). This is the conclusion of an international team of scientists treated to a virtual front row seat at Vesta for the past 10 months, courtesy of NASA's Dawn robotic probe. Their findings were presented during a NASA press conference on Thursday. As to why Vesta never made it to full planethood, scientists point to Jupiter. When the giant gas planet formed, nearby bodies such as Vesta found their orbits perturbed. 'Jupiter started to act like a spoon in a pot, stirring up the asteroid belt and the asteroids started bumping into one another,' said Dawn lead scientist Christopher Russell. 'If they're just out there gently orbiting and everything is going smoothly, then without Jupiter in the picture, they would gather mass and get bigger and bigger and bigger. But with Jupiter there, stirring the pot, then the asteroids start bumping into one another and breaking apart, so nothing grew in that region, but started to shrink.'"

Comments

Pluto?

[sunderland56]

So Pluto was deemed just another large chunk of space debris orbiting the earth, and hence not a planet. Vesta *is* just a large asteroid amongst a whole bunch of others, but it is a planet?

I'm confused now.

Re:Pluto?

[Anonymous Coward]

Planets orbit the sun, asteroids orbit something else. If a rock among other rocks is orbiting the sun, and it meets the other qualifications, it's a planet..

No. Asteroids orbit the sun.

A spherical object orbiting the sun and has cleared its orbit of other large objects is a planet.

Re:Pluto?

[Xtifr]

The abstract specifically says that Vesta is not an asteroid. When Ceres was reclassified as a dwarf planet, there was some question about Vesta, because it's not a proper spheroid. The question is: was it deformed by external forces or was it just never able to form a proper spheroid?

Since "baby planet" is not a proper IAU category, I think this means either A) it's a dwarf planet, like Pluto or Ceres, or B) the question is still open, but we've learned something new about its origin--a completely separate matter.

I think the IAU definitions are extremely silly, but I also think it's extremely silly think that Pluto is special, or any more deserving of planet status than Ceres, which was not considered a planet for many, many years. Personally, I'd rather see a definition of planet that includes Ceres and excludes Pluto than the reverse. (Though I'm also open to a definition that includes Ceres, Pluto, Luna, Ganymede, Titan, and more.)

Re:Pluto?

[colinrichardday]

So basically Vesta is Earth's aborted little sister.

Oh great, give the Republicans another excuse to cut science funding.

Re:Pluto?

[Sperbels]

(fusion-driven radiation emitters)

That doesn't seem to work for white dwarf stars.

Re:Pluto?

[osu-neko]

...space debris orbiting the earth...

Wait, Pluto orbits the Earth now?

Everything orbits the Earth. Heliocentrism is a fraud, brought to use by the same "scientists" as evolution, global warming, and that dubious round-earth theory. :p

Re:Pluto?

[Iskender]

I'd rather see a definition of planet that includes Ceres and excludes Pluto than the reverse.

I don't see what would put Ceres and Pluto in different categories under any system. Neither has cleared its orbit (I too think this is a silly criterion.) Both have the hydrostatic equilibrium thing going. Both orbit the sun directly.

Well, there *is* one peculiarity about Pluto: the barycenter of the Pluto-Charon system is outside both. While I dislike the clear the neighbourhood criterion I think this system is actually the strongest proof of the current planet definition being temporary: Pluto-Charon is a binary (dwarf) planet, yet no one has bothered to even mention Charon. Instead one of our current dwarf planets orbits an empty piece of space.

Re:Pluto?

[harperska]

No, what they have found, and what makes this newsworthy, is that Vesta's composition is much more like the terrestrials (Mercury, Venus, Earth, Luna, Mars) than what they believe Ceres' composition is. They now believe that Vesta belongs to the terrestrial family, having a silicate rock crust/mantle surrounding an iron core. Ceres, on the other hand, is probably made primarily of an ice crust/mantle with a rock core, putting it in the same family as the moons of the gas giants, and the Kuiper Belt objects like Pluto. So while Ceres and Vesta live in the same castle, they are adopted from different families.

They will know more when Dawn leaves Vesta and visits Ceres, though.

Re:Pluto?

[Red Flayer]

Since "baby planet" is not a proper IAU category, I think this means either A) it's a dwarf planet, like Pluto or Ceres, or B) the question is still open, but we've learned something new about its origin--a completely separate matter.

It's not a baby planet, it's not a dwarf planet. It's a proto-planet stuck in proto- state due to Jupiter.

I like to think of it as an aborted planet.

Obviously we need to outlaw Jupiter to prevent further proto-planet abortions.. Furthermore, we need full funding of a federal agency to ensure Jupiter isn't available to all wanton sinners who would otherwise bring a planet to full term.

Well, folks, seems to me like we finally figured out how to ensure NASA's budget isn't axed.

And it's a Good Thing (tm)

[Barbara, not Barbie]

... because otherwise, Vesta would have sucked up all the material there, including a lot that went into Jupiter, and become the equivalent of Jupiter, but closer.

That would have turned Mars into an asteroid belt ... and Earth into an undersized Mars.

And since Venus is just too darn close to the sun to support life ... another lifeless solar system.

Re:And it's a Good Thing (tm)

[chebucto]

Are you sure about that?

My astronomy is rusty, but I seem to recall that the inner planets are rocky because their proximity to the sun meant they were unable to build up the kind of atmosphere the gas giants did: their atmospheres boiled off before they could grow to the mammoth proportions of the gas giants.

Given the distance from the sun to Cerers, would Ceres ever have been able to form into a gas giant?

Anyway, who's to say Jupiter (or at least its moons) are lifeless? :|]

Re:And it's a Good Thing (tm)

[Solandri]

That was the old theory. The problem with studying the cosmology of star systems is that until recently we only had a sample of one. When they started finding planets orbiting other stars, they tended to be gas giants because of the methods used (orbit perturbations, light falloff due to occultations). But a surprising number of these gas giants orbit closely around their parent star. IIRC one has an orbit whose period is a few Earth-weeks. At this point, I think you can say all bets are off.

nice try, planetary scientists

[Trepidity]

You think this bone you're throwing to Vesta is going to make us forgive what you did to poor Pluto?

Please keep Baby Vesta safe!

[CuteSteveJobs]

Please don't tell Neil deGrasse Tyson about this or he will kill baby Vesta safe just like he killed its older sibling Pluto. This man is worse than the Pharaoh!

Dr. Neil deGrasse Tyson on killing Pluto: 'All I did was drive the getaway car'
http://www.theverge.com/2012/3/26/2903224/dr-neil-degrasse-tyson-killing-pluto-on-the-verge

Re:Pluto Takes Out Neptune

[petsounds]

And if a group of pro-Plutoans happen to make Neptune...disappear...does Pluto still get planetary status?