Dark, dangerous asteroids found lurking near Earth

[n2doc]

13:49 05 March 2010 by David Shiga, Houston

An infrared space telescope has spotted several very dark asteroids that have been lurking unseen near Earth's orbit. Their obscurity and tilted orbits have kept them hidden from surveys designed to detect things that might hit our planet.

Called the Wide-Field Infrared Survey Explorer (WISE), the new NASA telescope launched on 14 December on a mission to map the entire sky at infrared wavelengths. It began its survey in mid-January.

In its first six weeks of observations, it has discovered 16 previously unknown asteroids with orbits close to Earth's. Of these, 55 per cent reflect less than one-tenth of the sunlight that falls on them, which makes them difficult to spot with visible-light telescopes. One of these objects is as dark as fresh asphalt, reflecting less than 5 per cent of the light it receives.

Many of these dark asteroids have orbits that are steeply tilted relative to the plane in which all the planets and most asteroids orbit. This means telescopes surveying for asteroids may be missing many other objects with tilted orbits, because they spend most of their time looking in this plane.

more:

http://www.newscientist.com/article/dn18616-dark-dangerous-asteroids-found-lurking-near-earth.html

[Deep13]

1. I suppose white asteroids get a free pass.

:evilgrin:

Seriously, the whole study of minor planets is fascinating.

[RagAss]

2. Bring it On !

[byronius]

3. I'm curious as to the composition of the dark asteroid.

If they don't hit us, then they're resources.

I look forward to the days of autofac mining of the asteroid belt and the Oort cloud, so that Earth can be a garden again.

You might say that I'm a dreamer -- but I'm not the only one.

[Ian David]

6. We only have 1,500 years until the Earth's magnetic field dies and we go extinct.

This is what was on TV when I fell asleep last night:

POLE SHIFT VS. POLE REVERSAL

A pole shift is sometimes confused with a pole reversal, in which the magnetic poles switch places, so that north becomes south and vice-versa. From studying the magnetism of ancient rocks, scientists have learned that pole reversals have occurred at irregular intervals throughout the Earth's history, on average about once every 300,000 years. The last was about 780,000 years ago. According to University of California professor Gary Glatzmaier, who has modeled the phenomenon with a supercomputer, pole reversals are the result of the movement of molten iron in the Earth's outer core, which can cause twists in the planet's magnetic field. Pole reversals take place over thousands of years, during which time magnetic poles can show up in strange places — the magnetic north pole, for example, might suddenly show up on the island of Tahiti in the Pacific. Recently, some have pointed to magnetic field disturbances an area known as the South Atlantic Anomaly as a possible sign of an upcoming pole reversal — which conceivably could even occur in 2012, to the likely delight of apocalyptic believers — though scientists warn that it is not likely. If a pole reversal did happen, according to Stanford University geophysicist Norm Sleep, it might cause some strange phenomena. Auroras would be visible at the equator instead of the poles, compasses would cease to be reliable, and radio transmissions would be adversely effected. Cosmic rays might pierce the Earth's atmosphere more easily. Overall, though, life would still go on.

More:
http://channel.nationalgeographic.com/channel/ends-of-the-earth-pole-shift-2

See also:

South Atlantic Anomaly
From Wikipedia, the free encyclopedia
http://en.wikipedia.org/wiki/South_Atlantic_Anomaly

[muriel_volestrangler]

9. What were you eating before you fell asleep?

It seems to have induced some pretty far out dreams, anyway. Or maybe we should call tghem nightmares, if they were about extinction.

[Ian David]

10. Maybe. Anyway, one of the scientists on the program was saying that in about 1,500 years...

... the magnetic field that protects us from cosmic rays will be gone.

I haven't had time yet to research whether this is a far-out fringe thing or not.

[muriel_volestrangler]

11. But your link says (a) they don't know when

(b) it will affect compasses, maybe radio transmission, but life will go on. As it has done through the hundreds of ones there have already been. As for cosmics rays, there's a model that says the solar wind will protect the earth from cosmic rays.

[Ian David]

13. Well, that would be a relief. Thanks. n/t

[Ian David]

4. George W. Bush cut the budget for Asteroid detection.

He called them "Jesus Boulders."

I made the last part up.

[DavidDvorkin]

8. But the last part is so believable

I wouldn't be surprised if he thought that.

[damyank913]

12. Well that's because he was gonna bring democracy to the moon.

[Warpy]

5. While an asteroid hit would be nasty

it would also be pretty quick for most life on earth. Then the planet would start all over again with a new template and new environments for life to exploit.

Check out the graph of the mass extinction events at http://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extinction_event along with the article on the Great Dying. The planet has been through this sort of thing many times before and will likely go through it many times in the future.

It's the way things work.

[HysteryDiagnosis]

7. Sounds like dark matter... or a dark matter... or something of

the sort.... definitely not a gray matter or area. Gotta die from something they say.Didn't the Mayans draw pictures of these asteroids?? Kidding again.