There aren't any asteroids like that. There are asteroids which are very dark in visible light. They are more easily spotted in the infra red.
If there were mini black holes, they could hit Earth, perhaps, without being seen. But if there were such, then surely they would hit stars also, and we'd see stars disappear in the night sky.
As for large black holes, well they are end states of stars if they exist - so - as likely to hit Earth as stars - and - we'd see them a long way off through the accretion disk - and they would be most likely to miss the solar system altogether - stars are very far apart. That's not likely at all.
The asteroids of most danger to us, rather, are the ones that hit Earth from the direction of the sun. They are difficult to spot from Earth, and by the 2020s, we will still only have mapped out 50% of the ones up to a hundred meters or so orbiting inside of Earth. That is, unless the B612 foundation raise enough funds to launch their space telescope, which is designed to orbit inside of Earth, close to Venus. It would spot nearly all asteroids from 30 meters upwards by the 2020s.
The most dangerous ones are the ones of around 100 meters in size. They would most likely hit a remote area, as much of the Earth is still uninhabited, but they could hit a city, and that would destroy the city. We'd also have little warning if they approach from the Sun, perhaps a day or two. All we could do, probably, in that situation, is to evacuate the city as quickly as possible.
They are also the ones most likely to hit us. The larger ones are nearly all mapped out anyway and should have mapped out just about all of them by the 2020s. And even now, the chance of a dinosaur extinction type asteroid in the next century is only 1 in ten million.
This is the idea of the B612 foundation (named after the "Little Prince"'s planet) which has been working for some time on its Sentinel telescope idea
It would sit inside of Earth close to Venus's orbit giving it a good field of view of NEOs close to the sun. It looks away from the sun to avoid being blinded by it - and it can then see faint NEOs that are in between the Earth and the Sun which is the hardest place to spot them from our current Earth based surveys. Eventually it would spot just about everything out there that's in the vicinity of the Earth orbit.
Idea is that it would find nearly all potential impactors down to 40 meters diameter. And recently announced, that it should be able to spot them down to 20 meters diameter.
They hope to launch it in 2017 to 2018 on a Falcon 9. And to find 90% of NEOs down to 140 meters within ten years and a significant proportion of all NEOs down to 30 meters.
Anyone who is really keen to support them with their work can help them out with a donation on their website.
You can also sign this petition to increase funding of asteroid detection by 100 times
100x Declaration
I've now made a kindle booklet which goes into a lot more detail about the search for asteroids, early detection, and ways they could be deflected, or destroyed.
How Can You Tell If an Asteroid Is Headed Your Way?: The Truth Behind Asteroid Scare Stories, Robert Walker - Amazon.com
Also available as an article you can read online as
Giant Asteroid Headed Your Way? - How We Can Detect And Deflect Them
If there were mini black holes, they could hit Earth, perhaps, without being seen. But if there were such, then surely they would hit stars also, and we'd see stars disappear in the night sky.
As for large black holes, well they are end states of stars if they exist - so - as likely to hit Earth as stars - and - we'd see them a long way off through the accretion disk - and they would be most likely to miss the solar system altogether - stars are very far apart. That's not likely at all.
The asteroids of most danger to us, rather, are the ones that hit Earth from the direction of the sun. They are difficult to spot from Earth, and by the 2020s, we will still only have mapped out 50% of the ones up to a hundred meters or so orbiting inside of Earth. That is, unless the B612 foundation raise enough funds to launch their space telescope, which is designed to orbit inside of Earth, close to Venus. It would spot nearly all asteroids from 30 meters upwards by the 2020s.
The most dangerous ones are the ones of around 100 meters in size. They would most likely hit a remote area, as much of the Earth is still uninhabited, but they could hit a city, and that would destroy the city. We'd also have little warning if they approach from the Sun, perhaps a day or two. All we could do, probably, in that situation, is to evacuate the city as quickly as possible.
They are also the ones most likely to hit us. The larger ones are nearly all mapped out anyway and should have mapped out just about all of them by the 2020s. And even now, the chance of a dinosaur extinction type asteroid in the next century is only 1 in ten million.
This is the idea of the B612 foundation (named after the "Little Prince"'s planet) which has been working for some time on its Sentinel telescope idea
It would sit inside of Earth close to Venus's orbit giving it a good field of view of NEOs close to the sun. It looks away from the sun to avoid being blinded by it - and it can then see faint NEOs that are in between the Earth and the Sun which is the hardest place to spot them from our current Earth based surveys. Eventually it would spot just about everything out there that's in the vicinity of the Earth orbit.
Idea is that it would find nearly all potential impactors down to 40 meters diameter. And recently announced, that it should be able to spot them down to 20 meters diameter.
Anyone who is really keen to support them with their work can help them out with a donation on their website.
You can also sign this petition to increase funding of asteroid detection by 100 times
100x Declaration
I've now made a kindle booklet which goes into a lot more detail about the search for asteroids, early detection, and ways they could be deflected, or destroyed.
Also available as an article you can read online as
Giant Asteroid Headed Your Way? - How We Can Detect And Deflect Them
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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