Re: Night Sky : Sat Mar 23, 2013 10:16 am  

LBWR - this is my thread about Astronomy, where I occasionally inform anyone who might be interested about astronomy related stuff they might not know about, not a discourse with fools and trolls. You appear to be trying to hijack it into some personal pis-sing contest by making increasingly mad claims. You are behaving like an idiot and a boor, and nobody wants to discuss your lunatic theories, so please go away.

[Bullseye]

Re: Night Sky : Sat Mar 23, 2013 5:55 pm  

So, in the big scheme of things, how many other asteroids/comets etc have come as close as 30,000km that we know about? Should I blow the pension fund now?

Re: Night Sky : Sat Mar 23, 2013 6:15 pm  

Bullseye wrote:

So, in the big scheme of things, how many other asteroids/comets etc have come as close as 30,000km that we know about? Should I blow the pension fund now?

Here's a piccy of all known asteroids. The red ones are all near-earth asteroids. That we know of.



"It is estimated that there a likely to be bet. 100,000 to 1,000,000 similar asteroids as yet undiscovered with Earth-crossing orbits".

Re: Night Sky : Sat Mar 23, 2013 7:24 pm  

So all that pious hand wringing a few years ago about leaving all sorts of man-made cr@p floating around in space would be the equivalent of dropping one chewing gum wrapper at your local rubbish tip and worrying that it made the place look untidy ?

Re: Night Sky : Sun Mar 24, 2013 1:33 am  

JerryChicken wrote:

So all that pious hand wringing a few years ago about leaving all sorts of man-made cr@p floating around in space would be the equivalent of dropping one chewing gum wrapper at your local rubbish tip and worrying that it made the place look untidy ?

Yes and no, it's a different problem. Practically none of the known asteroids pose a threat whereas practically every piece of spce junk does simply because it is in or close to the orbits of satellites, the ISS and of course the occasional manned craft.

There are estimated to be tens of millions of bits of space debris, including about 600,000 objects larger than 1 cm orbiting Earth, and at least 16,000 larger than 10 cm. The problem is they don't need to be that big. This is the damage caused by a paint fleck that collided with a Space Shuttle window:

About a week ago the crew of the ISS actually hid in the Soyuz escape vehicle as one known piece of junk approached. Luckily it missed. But it's a huge problem.

Re: Night Sky : Mon Mar 25, 2013 2:39 pm  

Take a look at spaceweather.com http://www.spaceweather.com/ As well as giving updates on potential aurora sightings, it has a list of PHA's (Potentially Hazardous Asteroids) that are known to come close to, or cross, the Earth's orbit, and also shows a plot of their orbits. However, the worrying word is "Known"

Take a look at spaceweather.com http://www.spaceweather.com/ As well as giving updates on potential aurora sightings, it has a list of PHA's (Potentially Hazardous Asteroids) that are known to come close to, or cross, the Earth's orbit, and also shows a plot of their orbits. However, the worrying word is "Known"

Re: Night Sky : Tue Mar 26, 2013 1:08 am  

Awe-inspiring image of the jets streaming from galaxy Hercules A, an object which is 2 billion light years* away.



Hercules A, the yellowy blob at centre of the image, is one BIG galaxy. For comparison, our own Milky Way galaxy is about 100,000 light years in diameter and it contains about 200 billion stars. Hercules A, is roughly 1,000 times more massive than the Milky Way and has at the centre a 2.5-billion-solar-mass central black hole, which spews out the jets at near-light speed.

The jets, which are only visible to a radio telescope, are about one-and-a-half million light-years long.



* 1 light-year = the distance light travels in 1 year at 186,000 miles per second.

[Wheels]

Re: Night Sky : Tue Mar 26, 2013 1:19 pm  

I can't even begin to get my head around those figures.

Re: Night Sky : Tue Mar 26, 2013 1:42 pm  

Wheels wrote:

I can't even begin to get my head around those figures.

a lightyear is about 9480000000000000 metres, that should make it a bit clearer for you

Re: Night Sky : Thu May 02, 2013 12:32 pm  

Next time you are thinking of complaining about the weather, it could be worse - you could be in the giant hurricane over Saturn's north pole