Long-lost near-Earth asteroid spotted: New Scientist

[Ivan Seeking]

A large and potentially hazardous asteroid that went missing for almost 66 years ago was re-discovered by astronomers on Wednesday morning. The good news is that its next fly-by, on 4 November, will miss the Earth by a relatively comfortable seven million kilometres.

http://www.newscientist.com/news/news.jsp?id=ns99994285

 

[zoobyshoe]

This is going to happen a little over two weeks from now (17days).
7 million kilometers is 4,349,590 miles. Hermes is 1-2 kilometers in diameter, roughly 5/8 to 1 1/4 miles. They're saying this one doesn't match the Hermes orbit perfectly, but they're pretty sure it's Hermes.

Anyway 4.35 million miles is too close for my taste. Why can't these rogue celestial wanderers stay out of the solar system altogether?

 

[Ivan Seeking]

Originally posted by zoobyshoe
This is going to happen a little over two weeks from now (17days).
7 million kilometers is 4,349,590 miles. Hermes is 1-2 kilometers in diameter, roughly 5/8 to 1 1/4 miles. They're saying this one doesn't match the Hermes orbit perfectly, but they're pretty sure it's Hermes.

Anyway 4.35 million miles is too close for my taste. Why can't these rogue celestial wanderers stay out of the solar system altogether?

This is the deep, dark secret of Chicken Little: He is an astronomer.

For years I have had a Ziggy cartoon posted in my office. First we see an astronomical observatory with its telescope pointed towards the sky. Five scientists are running from the building; screaming and panicking due to [by implication] what was just seen in the scope. Ziggy looks at the reader with resignation and says: Now what?

 

[Phobos]

Originally posted by Ivan Seeking
Now what?

The best bet is to either deflect it (change its path) or change its velocity (so it doesn't appear at the same place as the Earth at the same time).

Strategies: (Robert Burnham, Astronomy Magazine, Dec 02)

Nuke it – explosion next to or just below surface to vaporize a portion…offgases change the orbit
Smack it – direct impact with fast, massive, inert object to deflect its course
Warm it/cool it – Yarkovsky effect to generate thrust*
Cook it – giant mylar mirror to focus sunlight…jetting vapor alters the orbit

* - or dump lots of reflective/dark material on it (chalk/ice or charcoal/soot) (D. Chandler, Astronomy Magazine, Dec 02)

 

[Ivan Seeking]

Mystery Asteroid, Hermes, May Have a Partner

Astronomers have apparently discovered an interesting twist to one of the greatest asteroid mysteries of all time. Hermes, a space rock lost to science for 66 years and recently rediscovered, could actually be a pair of orbiting asteroids, new radar observations suggest.

And a strange pair, indeed.

http://www.space.com/scienceastronomy/hermes_binary_031021.html

 

[zoobyshoe]

Great, they're multiplying.

 

[gunblaze]

at its not coming directly towards earth.....Seven million kilometres is a safe distance!