Slashdot Mirror
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.
Out of sight, out of mind seems to be the current mindset. We'll probably be wiped out by one at some point.
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 we can see an asteroid with the naked eye it might be time to duck.
Its almost certainly too late to call B ruce Willis
that means the Vorlons are using mass drivers to attack your home world.
I was kind of surprised by that factoid. Especially since the WISE data hasn't been completely released yet.
Carter, I can see my house!
Get free satoshi (Bitcoin) and Dogecoins
Search for asteroids without taking into account where the known ones are. See which fraction of the asteroids you discover were already known.
It's not that hard, you know how much of the sky you've looked at. You know the sizes, positions, and velocities of all the asteroids you've cataloged. From there it's a non-trivial but certainly doable calculation to come up with an estimate of the total number.
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!"
data from impact areas on moon, discovery rate, increase in counts with improvement in instruments are some factors:
http://www.lsst.org/lsst/publi...
First, Scott does not mention, that most dangerous asteroids are found
>95% of 1 km size asteroids
>90% for 500 m size asteroids
~60-70% 300 m size asteroids
so yes, we know 1% of asteroids, but still - the danger now for a person to be killed by asteroid is more than 100 times less, than it was two decades ago
another problem with his video, that he omits to mention, that inner asteroids are either harmless, or if they intersect earth orbit - they could be tracked at dusk/dawn ( just like venus is visible - and venus is quite far from being able to hit earth, so closer asteroids and relatively big asteroids are easier to find )
then about finding inner asteroids with space crafts - it is not just B612 foundation, which deals with that , but there are other proposals
http://arxiv.org/abs/1503.0794... - which is really cheap ( though idea requires some more development )
or http://xxx.lanl.gov/abs/1501.0... neocam - the paper has a proof that it is somewhat more realistic than B612 proposal and is not less efficient.
It's not that hard, you know how much of the sky you've looked at. You know the sizes, positions, and velocities of all the asteroids you've cataloged. From there it's a non-trivial but certainly doable calculation to come up with an estimate of the total number.
That only works if you have some way to make reasonable assumptions or statistical inferences about what is in the bits of the sky you haven't looked. It's not clear to me if such assumptions are appropriate here since we've routinely been surprised by what we find in bits of the sky where we haven't looked carefully. Plus isn't part of the problem just that asteroids can be really hard to see even when we are looking right at them?
Meteors are "seen" in the night sky.
No one will "see" an asteroid, near Earth or not, in the night sky without the aid of one fuck'n big ass optical telescope or a very large and powerful radar facility.
You Could See Asteroids In the Night Sky...
love is just extroverted narcissism
If you can see Asteroids in the night sky, you'll be able to see Space Invaders from the night sky, too!
And you assume that you found ALL the asteroids in the sky you've looked at.
Also, asteroids that moved into your field of study.
There are two types of people in the world: Those who crave closure
What would I do if I could see an asteroid? Shit my pants, of course.
Easy: We know the mass of the early solar system. You can back out how much free material is floating around in the system simply by knowing the mass of the other planets.
As for number and distribution, that's where statistics and asteroid formation models come into play.
Asteroids are very difficult to find, owing to their small size (relatively speaking) and their low albedo.
On getting a glimpse of something strange in the telescope:
"It makes me realize how desperately alone the Earth is, hanging in space like a fleck of food floating in the ocean, sooner or later to be swallowed up by some creature floating by."
https://archive.org/details/Te...
The distribution of asteroids that we can detect follow a power law: for a given cross-sectional area, the number is crudely inversely proportional. This not only holds for the biggest ones which we can observe in telescopes, but also meteorite impacts with the Earth and Moon. So we have estimates of asteroid populations by size from the largest to well below the minimum size which can cause harm to us on Earth.
If I were doing this, I'd have a probe go through the asteroid belt and catalogue the number of asteroids it identifies. Then I'd compare that to the number I'd catalogued previously. That misses rogue asteroids, of course, and assumes that asteroid distribution is uniform throughout the belt.
It is still not much more reliable than a WAG. Obviously it isn't a wild guess and is based on fairly sound logic but it really is nothing more than a guess when you get down to it. There is no way to be certain that one is missing an area with a heavy concentration of NEO objects. There is simply no way to be certain. Even hazarding a guess seems counterintuitive, what does it benefit to spread the misinformation about there being only 1% discovered? Theoretically we could have discovered them all. We could have only discovered 0.001%. What matters is that we discover the big one before it hits and that only matters if we are going to be able to do something about it. If it is going to wipe out our species then that discovery matters not one bit.
"So long and thanks for all the fish."
I clicked on your first link to double check something and I am not sure that I agree with your view. No, we do not know the total mass of the solar system. We have a working hypothesis but this is not knowing. We could be right, we could be wrong. Additionally, there is no limit to what could be coming in from other solar systems so concluding that we know the original mass seems, to me at least, to be of absolutely no importance when it comes to estimating the prevalence or rate of the occurance of NEO. I find the trend to state theoretical results as factual a bit disturbing and dishonest. This could be changed by simply saying, "We believe..." Or, "The currently working hypothesis..." Instead we have many people, yourself included, who are stating theoretical, nay - hypothetical (even less likely to be true), as being factual conclusions.
Take my disagreement as you will. It likely will have no impact on your beliefs or the way you conduct yourself. I am certainly the bad guy for wanting open and honest communication. I obviously do not understand something...
It is okay but, frankly, I do find it telling and have no choice but to use it as judgment when considering other bits of information that one may try to convey.
"So long and thanks for all the fish."
Same way we "know" that 80% of rape victims never report it.
We pull a number out of our ass that will help promote the current agenda.
Yeah, those evil SJWs and feminazis with their "anti-rape" agenda. Whatever happened to free choice?
Oh, wait...
To have a right to do a thing is not at all the same as to be right in doing it
I'm still not sure how In intend to celebrate the IMPENDING DISMAL FAILURE of the EADP Mission fund raiser to raise $200k for producing a set of plans to for a viable asteroid deflection/destruction mission. Win or lose, something besides NOTHING ready to deploy on short notice. What kind of cake would be appropriate for this level of fail?
185 people have contributed $8,803 of $200k. Two of them are me.
WHAT IF a simple test appeared out of the blue one day... something that you could not ignore. Despite any best effort to put a positive spin on it, the moment it flicks into your mind you think to yourself, "All is lost."
A TEST as clear and obvious as it is simple. Something that no amount of explaining away could touch, for which no rational excuse was possible, and even the most carefully constructed counter-arguments reveal themselves as elaborate denial mechanisms, unworthy even of response.
Despite hundreds of trillions of real and imagined dollars in circulation, a populous modern society of the self-proclaimed 'age of enlightenment' cannot raise an amount of money equivalent to that of a single yearly CEO's salary...
We have built the Internet... and connected our world... to.... well shit.
I can't even think up a single good reason anymore.
It all seems like so much tripe, if we're in the process of failing this simple test.
<blink>down the rabbit hole</blink>
About haft the mass of the asteroid belt is in the 4 largest bodies. Also note that is half of the *estimated total mass*. We have very accurate orbital models and combined with what we have seen we can get fairly accurate estimates. It is very unlikely to get a big surprise. Because as you say, it would be easy to detect it.
The Grey Goo disaster happened 3 billion years ago. This rock is covered in self replicating machines!