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STEREO Spacecraft To Explore Earth's L4 and L5
Hugh Pickens writes "Launched on October 25, 2006, NASA's twin Solar Terrestrial Relations Observatory (STEREO) spacecraft are about to enter the L4 and L5 Lagrangian points, special points in our orbit around which spacecraft and other objects can loiter because the gravitational pull of earth and the sun balances the forces from the object's orbital motion. (The spacecraft won't linger at the Lagrangian points; they are just passing through.) 'These places may hold small asteroids, which could be leftovers from a Mars-sized planet that formed billions of years ago,' said NASA Project Scientist Michael Kaiser. STEREO will look for asteroids with a wide-field-of-view telescope. 'If we discover the asteroids have the same composition as the Earth and moon, it will support Belbruno and Gott's version of the giant impact theory. The asteroids themselves could well be left-over from the formation of the solar system.' L4 and L5 are also good places to observe space weather. 'With both the sun and Earth in view, we could track solar storms and watch them evolve as they move toward Earth. Also, since we could see sides of the sun not visible from Earth, we would have a few days warning before stormy regions on the solar surface rotate to become directed at Earth,' says Kaiser."
'These places may hold small asteroids, which could be leftovers from a Mars-sized planet that formed billions of years ago,'
Can we not confirm the existence of these using telescopes on Earth or in orbit?
Get off my Lagrangian points you young hoodlums!
Genesis 1:32 And God typed
If its out there, the atheist community isn't going to be happy.
So your telling me that NASA is parking the worlds most expensive STEREO in the only free parking spots in the solar system? Next you're gonna tell me they used it to blast "In your eyes"...
L4 and L5 are stable, means that a force pushes objects back in the direction of those points regardless of the direction, because they are a local potential minimum.
L1, L2, L3 are indeed unstable, but there exists an orbit around those points, which is stable.
That (the lagrange points being unstable equilibria) is true of L1, L2 and L3 (all on the Earth-Sun line, L1 between Earth and Sun, L2 outside the Earth's orbit and L3 round the other side of the Sun). L4 and L5, OTOH, are stable equilibria and junk can collect there. The equivalent points for Jupiter have observable collections of asteroids in them.
actually 4 and 5 are stable, from wikipedia:
In contrast to the collinear Lagrangian points, the triangular points (L4 and L5) are stable equilibria (cf. attractor), provided that the ratio of M1/M2 is greater than 24.96.[5][6] This is the case for the Sunâ"Earth and, by a smaller margin, the Earthâ"Moon systems. When a body at these points is perturbed, it moves away from the point, but the Coriolis effect bends the object's path into a stable, kidney beanâshaped orbit around the point (as seen in the rotating frame of reference). However, in the Earthâ"Moon case, the problem of stability is greatly complicated by the appreciable solar gravitational influence.[7]
source
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"The asteroids themselves could well be left-over from the formation of the solar system."
No way. The Lagrange points are theoretical solutions to the 3 body problem. The Earth-Sun system is not 3 body. The Earth's relationship with the moon is such that their common center is outside the Earth. Fluctuations in the gravity field of the co-orbiting the Earth-moon would guarantee no permanently stable solution.
The L4 and L5 points are not gravity wells. They are the tops of gravity hills (see the top map at http://en.wikipedia.org/wiki/Lagrange_point ). The slightest perturbation will result in a body at those points to orbit the point and eventually be thrown out. We have satellites at Lagrange points now and they are operated in that way. They orbit the L point, and have station keeping motors to keep them orbiting them.
The above is doubly applicable if the theorized collision scenario occurred. The moon supposedly came from the collision of the Earth and a Mars sized object. Such a collision would preclude their being any L points that remained stable throughout, making it impossible that there should be asteroids remaining in such points since the beginning of the solar system.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
IANAAP but I think that is only true for L1-L3. IIRC L4 and L5 would be relatively stable as long as a body had the correct momentum when it entered them.
Dedicated Cthulhu Cultist since 4523 BC.
utter rubbish, in an informal environment like this wikipedia is fine. Indeed you should not use it in papers and such, that' splain silly, but for a quick lookup of fact, together with a quick check if the content seems unreasonable or not, it's fine
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When I read the headline I thought if this worked out that there might be help for my L4 and L5 back problems.
In space, no one can hear your STEREO
The team is inviting the public to participate in the search by viewing the data and filing a report at: >
There's a missing link in the article for where you can help out. The link meant to posted is:
You are just as likely to receive a failing grade if you sign your paper Anonymous Coward.
So your point was, what?--rules for college assignments should apply to slashdot?
The new STEREO spacecraft is an improved version of MONO. The next spacecraft, scheduled to be released in 10 years, will be called SURROUND.
Sorry, I'll be here all week.
"These places may hold small asteroids, which could be leftovers from a Mars-sized planet that formed billions of years ago"
So... Mars?
As a researching using STEREO data, I wrote a piece on some of the logistics of this, and what we may find.
http://scientificblogging.com/daytime_astronomer/secrets_l4l5_gravity_wells
The summary is: we've already seen a bit in an earlier roll so we know there's stuff there, we lose use of the in-situ to explore L4/L5 so we have to balance that with our core science, there's a higher risk to the detectors due to dust, but what the heck, we have to pass through it anyway. We may find any of: dust, the moon's progenitor, and earth-killer, more dust.
A.
I finally figured out what ZZ Top was singing about. Earth's and the Sun's gravitational limbo land.
But but but it's tainted with lieeesssss!!!!!11
which will turn the STEREO spacecraft into interplanetary techno-confetti upon impact.
"These places may hold small asteroids..."
Really? We don't KNOW?
Checking wiki, apparently we're not even sure of what's in the L4/L5s in the Earth/Moon system. A Japanese probe failed to find the expected Kordylewski clouds.
I'm well aware of the vasty nature of space, but I guess I'm sometimes startled about how ignorant we are about our own very local neighborhood...
-Styopa
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Sig? No thanks. I don't smoke.
"which could be leftovers from a Mars-sized planet that formed billions of years ago"
I wonder which planet that could be!
It's full of stars!
"Don't be a martyr -- BE THE ONE WHO GOT AWAY!"
Who knows, maybe they'll see our Antichthon!
Does anyone remember Independence War and Independence War 2? The first one is almost 11 years old and the second is almost 8 years old. They used Lagrange points for a type of FTL travel. It was a cool game and being I was still in high school, I didn't know much about that level of astrophysics.