When minor planets Ceres and Vesta rock the Earth into chaos

Jul 14, 2011
Fig. 1. Observations of Ceres by NASA's Hubble Space Telescope. Credit: NASA, ESA, J.-Y. Li (University of Maryland) and G. Bacon (STScI).

Astronomy & Astrophysics is publishing a new study of the orbital evolution of minor planets Ceres and Vesta, a few days before the flyby of Vesta by the Dawn spacecraft. A team of astronomers found that close encounters among these bodies lead to strong chaotic behavior of their orbits, as well as of the Earth's eccentricity. This means, in particular, that the Earth's past orbit cannot be reconstructed beyond 60 million years.

Astronomy & Astrophysics is publishing numerical simulations of the long-term evolution of the orbits of minor Ceres and Vesta, which are the largest bodies in the asteroid belt, between Mars and Jupiter. Ceres is 6000 times less massive than the Earth and almost 80 times less massive than our Moon. Vesta is almost four times less massive than Ceres. These two minor bodies, long thought to peacefully orbit in the asteroid belt, are found to affect their large neighbors and, in particular, the Earth in a way that had not been anticipated. This is showed in the new astronomical computations released by Jacques Laskar from Paris Observatory and his colleagues.

When minor planets Ceres and Vesta rock the Earth into chaos
Fig. 2. Vesta. NASA's Dawn spacecraft obtained this image with its framing camera on July 1, 2011. It was taken from a distance about 100,000 kilometers away from Vesta. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Although small, Ceres and Vesta gravitationally interact together and with the other planets of the Solar System. Because of these interactions, they are continuously pulled or pushed slightly out of their initial orbit. Calculations show that, after some time, these effects do not average out. Consequently, the bodies leave their initial orbits and, more importantly, their orbits are chaotic, meaning that we cannot predict their positions. The two bodies also have a significant probability of impacting each other, estimated at 0.2% per billion year. Last but not least, Ceres and Vesta gravitationally interact with the Earth, whose orbit also becomes unpredictable after only 60 million years. This means that the Earth's eccentricity, which affects the large climatic variations on its surface, cannot be traced back more than 60 million years ago. This is indeed bad news for Paleoclimate studies.

This unexpected discovery comes at a time when both objects are the targets of the NASA/Dawn mission. The Dawn probe will encounter Ceres in February 2015. At present, Dawn is approaching , and the flyby will occur on this coming Saturday, July 16, 2011.

Explore further: NASA's Maven explorer arrives at Mars after year

More information: Strong chaos induced by close encounters with Ceres and Vesta, by J. Laskar, M. et al., Published in Astronomy & Astrophysics, 2011, vol. 532, L4

Provided by Astronomy and Astrophyisics

4.8 /5 (16 votes)

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User comments : 12

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Teachey
5 / 5 (7) Jul 14, 2011
The Dawn spacecraft is actually going to orbit Vesta for a year. Orbit insertion is on Saturday, it's not a flyby.
jscroft
3.7 / 5 (6) Jul 14, 2011
This means, in particular, that the Earth's past orbit cannot be reconstructed beyond 60 million years.


There was a major extinction event right around then. Any connection, I wonder?
BradynStanaway
3 / 5 (1) Jul 14, 2011
@jscroft

Curiouser and curiouser..
Waterdog
4.5 / 5 (4) Jul 14, 2011
Could help to explain a lot of Pre-human climate changes. Both hotter and ice ages.
lengould100
4.8 / 5 (4) Jul 14, 2011
Agreed Waterdog. Didn't the first ice age cycle on earth start about that long ago? Of course the article doesn't exactly say that something significant actually happened 60 my ago.
LKD
3 / 5 (3) Jul 14, 2011
I am curious what implication this has on the moon's orbit and its evolution from an Earth borne mass to it's present form.
Shootist
1.3 / 5 (3) Jul 14, 2011
Agreed Waterdog. Didn't the first ice age cycle on earth start about that long ago? Of course the article doesn't exactly say that something significant actually happened 60 my ago.


The Karoo Ice Age occurred some 650Mya.
Waterdog
5 / 5 (1) Jul 14, 2011
I believe the Karoo Ice Age occurred from 360 to 260 million years ago, but there was the Paleocene-Eocene Thermal Maximum, or PETM that was about 57 million years ago.
Jonseer
3.4 / 5 (5) Jul 14, 2011
This article is poorly written.

It seems to say Vesta and Ceres are responsible for changes in Earth's orbit, when what they are saying is their calculations that demonstrate Vesta and Ceres have chaotic orbits also demonstrates that the Earth's orbit can't be reconstructed back beyond 60 million years.

THE CONNECTION that the article seems to infer seems to be a product of bad translation.

In any case, the notion that Earth would be so affected, and not Venus, not Mars is pretty good evidence that the original proof is not about Vesta and Ceres affecting Earth's orbit, but two separate ones incorrectly interpreted and written as a result as one.
Jonseer
1 / 5 (2) Jul 14, 2011
This article is poorly written.

It seems to say the research indicates Vesta and Ceres are responsible for changes in Earth's orbit.

A closer reading indicates that they are separate conclusions.

What they are saying is the calculations that demonstrate Vesta and Ceres have chaotic orbits also demonstrates that the Earth's orbit can't be reconstructed back beyond 60 million years, but both are separate phenomena.

THE CONNECTION that the article seems to infer between the two seems to be a product of bad translation.

In any case, the notion that Earth would be so affected by Vesta and Ceres without figuring in the effects of Venus, Mercury and Mars all much closer and larger, let alone ignore the effects Vesta and Ceres would have on them as well is pretty good evidence that the original proof is not about Vesta and Ceres affecting Earth's orbit, but two separate ones incorrectly interpreted and written as a result as one.
antialias_physorg
5 / 5 (4) Jul 15, 2011
In any case, the notion that Earth would be so affected by Vesta and Ceres without figuring in the effects of Venus, Mercury and Mars all much closer and larger,...


I think you get the wrong impression. The article describes the difference between making calculations which include only the planets and those which also include the major asteroids (in the paper they include the 5 major asteroids with the effect being particularly pronounced due to Ceres and Vesta)

So yes: Ceres and Vesta are (also) responsible for changes in Earth's orbit.
(along with all the other planets. But that was never being drawn into question here. That fact was already known long before)

With the inability to predict ceres' and Vesta's paths correctly beyond a certain timeline this puts a hard upper limit on our prediction (or history) of the Earth's orbit.

Full paper can be found here:
http://www.obspm....7504.pdf
Jonseer
1 / 5 (2) Aug 15, 2011
I think you get the wrong impression.....So yes: Ceres and Vesta are (also) responsible for changes in Earth's orbit.
http://www.obspm....7504.pdf


I wasn't referring to the paper or what it said, but to the article, and its lack of clarity.

THE PROBLEM WITH THE ARTICLE IS in particular this line:

The two bodies also have a significant probability of impacting each other, estimated at 0.2% per billion year. Last but not least, Ceres and Vesta gravitationally interact with the Earth, WHOSE ORBIT ALSO becomes unpredictable after only 60 million years.

the Earth's orbit the article says is Unpredictable beyond 60,000,000 years regardless of Ceres and Vesta. They only make it worse.

That is as you say.

The article leaves the impression they are THE cause, because it mixes the info and makes connections inadvertently between what they say about the orbits.

You KNOW so you compensate for the lack of clarity. Those who don't can't. So its confusing.