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General Discussion => Science & Nature => Topic started by: sam on July 05, 2011, 12:35

Title: Space Pictures This Week: Lunar Sunrise, Saturn Slice, More
Post by: sam on July 05, 2011, 12:35
Quote
A black hole two billion times as massive as the sun spits out jets of radiation in an artist's impression of ULAS J1120 0641, the most distant quasar yet discovered. The object was described in this week's issue of the journal Nature.

http://news.nationalgeographic.com/news/2011/06/pictures/110630-best-space-pictures-stars-quasar-titan-saturn-moon-lunar-151-science/

Title: Re: Space Pictures This Week: Lunar Sunrise, Saturn Slice, More
Post by: Simon on July 05, 2011, 12:46
2 billion times the sun?  It's just beyond our imaginations, isn't it?
Title: Re: Space Pictures This Week: Lunar Sunrise, Saturn Slice, More
Post by: sam on July 05, 2011, 12:53
yes.. when you put things into scale its just amazing;: e.g. http://vlad.bailescu.ro/wp-content/uploads/2008/10/planet_and_stars_scale_comparison.jpg
Title: Re: Space Pictures This Week: Lunar Sunrise, Saturn Slice, More
Post by: Clive on July 05, 2011, 13:05
That's mass don't forget Simon - not size.  Though I'm sure Sam could do a back of an envelope calculation on size in comparison to our Sun.
Title: Re: Space Pictures This Week: Lunar Sunrise, Saturn Slice, More
Post by: sam on July 05, 2011, 13:18
oh yes, mass it was. Ummm. I could do a calculation but would have to make a few assumptions about the contents of the star and the spectral age.

For stars like the Sun the radius is closely related to the the Mass - actually not far off 1:1, its actually R ~ M^(0.78) so a star 2 times the mass of the Sun would be 1.717 larger. For a star 2billion times larger, its much different and hence this relation would fall apart. Different physics going on inside it.

Black hole are exceedingly small. This is a quasar and hence would be smaller than the Sun.
Title: Re: Space Pictures This Week: Lunar Sunrise, Saturn Slice, More
Post by: Simon on July 05, 2011, 13:20
:stars:
Title: Re: Space Pictures This Week: Lunar Sunrise, Saturn Slice, More
Post by: sam on July 05, 2011, 13:30
 ;D I could be worse. I thought I was quite straight forward there.

Maybe this is better: http://en.wikipedia.org/wiki/Quasar
Title: Re: Space Pictures This Week: Lunar Sunrise, Saturn Slice, More
Post by: Simon on July 05, 2011, 13:52
I'll look later.  :)
Title: Re: Space Pictures This Week: Lunar Sunrise, Saturn Slice, More
Post by: Clive on July 05, 2011, 20:52
Mass and size are difficult concepts for most people, but you gave a good explanation.   :)
Title: Re: Space Pictures This Week: Lunar Sunrise, Saturn Slice, More
Post by: sam on July 05, 2011, 21:52
maybe too much maths.
Title: Re: Space Pictures This Week: Lunar Sunrise, Saturn Slice, More
Post by: Clive on July 05, 2011, 22:25
Can't see how you could have got away with less.   :dunno:
Title: Re: Space Pictures This Week: Lunar Sunrise, Saturn Slice, More
Post by: sam on July 05, 2011, 22:34
Ummm...

Most of the time mass is proportional to radius but in the case of extreme objects this is not the case. In red giants the radius is much larger due to convection currents. In the case of neutrons stars its much smaller because of the strong force holding it all together.

How's that.No maths.
Title: Re: Space Pictures This Week: Lunar Sunrise, Saturn Slice, More
Post by: Clive on July 06, 2011, 07:57
 :clap: