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What If You Could See Asteroids In the Night Sky?
An anonymous reader writes: As part of Asteroid Day a 360-degree video rendering the night sky with the population of near-earth asteroids included has been created by 'Astronogamer' Scott Manley. The video shows how the Earth flies through a cloud of asteroids on its journey around the sun, and yet we've only discovered about 1% of the near earth asteroid population.
The video shows how the Earth flies through a cloud of asteroids on its journey around the sun, and yet we've only discovered about 1% of the near earth asteroid population.
Ok, how do we know what we haven't discovered yet? I know statistical techniques for estimating population sizes of wildlife. (Catch some number, tag and release, catch a bunch more and see how many tagged ones you catch which gives you a population estimate) I'm not sure those techniques are applicable here. Anybody have any idea how this estimate was arrived at or is it taken straight out of someone's derriere? Measurements of orbit perturbations? Something else?
If it's just a count of objects, "1%" doesn't mean much anyway. We should be much more interested in mapping Mass. A 1kg asteroid is mostly harmless (to Earth, though it could be catastrophic for man-made satellites). This may be a faulty assumption, but I would think the larger, more dangerous objects would be detected first. If so, 1% of the total number may represent something like 50% of the total mass of all NEAs. If that's true, it's far less ominous than saying "99% of potential Earth-impacting asteroids are currently hidden!!!1!"
There is one asteroid, Vesta, which can be seen every couple of years or so by people with decent (not exceptional) naked eye eyesight. I've seen it a few times, you just need to know exactly where to look and a have a bit of stargazing experience at picking out faint objects. Its last opposition was in April 2014. Without looking it up I'd guess the next is in late 2015 or early 2016.