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+--- Thread: Detecting Lagrange Moons (/showthread.php?tid=4081)
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Detecting Lagrange Moons - Cray - 03-27-2019
If a dark (low albedo), carbonaceous asteroid about 5-10km long was in Earth's L5 point, would it reasonably escape notice by astronomers until the 1960s?
RE: Detecting Lagrange Moons - Rynn - 03-28-2019
I have no idea but I pretty sure that most of the mapping of asteroids occured in the latter half of the 21st century...
RE: Detecting Lagrange Moons - stevebowers - 03-28-2019
Cruithne is the closest thing we have to a Lagrangian asteroid - it is 5km long, and was discovered in 1986. So, no. An Earth/Sun Trojan would probably be missed in the 1960s, but we would probably have seen it by now.
RE: Detecting Lagrange Moons - Cray - 03-29-2019
(03-28-2019, 06:47 PM)stevebowers Wrote: Cruithne is the closest thing we have to a Lagrangian asteroid - it is 5km long, and was discovered in 1986. So, no. An Earth/Sun Trojan would probably be missed in the 1960s, but we would probably have seen it by now.
Excellent fit on size and a good example.
But Cruithne never gets closer than 12 million kilometers from Earth. The proposed stealthy asteroid is about 400,000km from Earth.
RE: Detecting Lagrange Moons - Drashner1 - 03-29-2019
I am no astronomer, but my understanding is that a lot of astronomical discoveries have historically come about because of the occultation of some further away object that was being observed by something much closer.
With that in mind, I think the answer to your question might come down to whether or not the asteroid passed in front of something else that was being looked at. Being so close to Earth, it seems to me the odds might be higher that it would pass in front of something else and be detected sooner rather than later (there is also the issue of people deliberately looking in the LaGrange points for asteroids). OTOH, while the volume size you mention is vastly smaller than the rest of the solar system it is still huge in comparison with Earthly scales - so much so that a considerable time might pass before the right set of circumstances came together to result in the detection of the asteroid.
My 2c worth,
Todd
RE: Detecting Lagrange Moons - Stargate38 - 10-05-2019
2010 TK7 is a true Trojan, unlike Cruithne (which is in a horseshoe orbit, and therefore a different type of co-orbital body).
EDIT: Oops. I didn't notice this thread hadn't been posted in for 6 months.
RE: Detecting Lagrange Moons - Drashner1 - 10-05-2019
(10-05-2019, 03:31 AM)Stargate38 Wrote: 2010 TK7 is a true Trojan, unlike Cruithne (which is in a horseshoe orbit, and therefore a different type of co-orbital body).
EDIT: Oops. I didn't notice this thread hadn't been posted in for 6 months.
Last bit first - No worries about posting to an old thread. I gather some forums really don't like that, but we're generally not terribly fussed about it as long as the new post adds to the discussion or knowledge base of the community or the like. And yours does
Re 2010 TK7 - that's interesting! I hadn't heard about this and honestly wasn't entirely sure Trojan objects (orbiting 60 degrees ahead/behind the planet) were possible for terrestrial bodies. You almost only ever hear about them in connection with gas giants in both fiction and RL.
This being OA, what part (if any) do you think this body might play in the history of the Solar System in the OA future? What (if anything) might it be used for? Would it still exist in the 'Present Day' in some capacity or would it have been consumed or moved long ago?
Thoughts?
Todd
RE: Detecting Lagrange Moons - stevebowers - 10-06-2019
(03-29-2019, 06:51 AM)Cray Wrote:Are you talking about the Earth/Moon L5 point, or the Earth/Sun L5 point? Ann asteroid in the Earth/Moon L5 point would have an average distance of 384,400 km, although it would probably oscillate significantly around that distance.(03-28-2019, 06:47 PM)stevebowers Wrote: Cruithne is the closest thing we have to a Lagrangian asteroid - it is 5km long, and was discovered in 1986. So, no. An Earth/Sun Trojan would probably be missed in the 1960s, but we would probably have seen it by now.
Excellent fit on size and a good example.
But Cruithne never gets closer than 12 million kilometers from Earth. The proposed stealthy asteroid is about 400,000km from Earth.
RE: Detecting Lagrange Moons - Drashner1 - 10-06-2019
(10-06-2019, 07:17 AM)stevebowers Wrote: Are you talking about the Earth/Moon L5 point, or the Earth/Sun L5 point? Ann asteroid in the Earth/Moon L5 point would have an average distance of 384,400 km, although it would probably oscillate significantly around that distance.
Looking at the wikipedia article it is in the preceding Earth-Sol L - Point.
It is apparently oscillating around a good bit as well. But it is not in one of the Earth/Moon L-points.
Todd
RE: Detecting Lagrange Moons - stevebowers - 10-06-2019
I think Cray was asking about the Earth/Moon L5 point. I'm sure that a small asteroid in that position would have been seen before Cruithne.