[Martin]

Interactive black hole feature at Hubblesite
http://hubblesite.or...holes/home.html

Several SFN people liked this. Discussion here:
http://www.sciencefo...ead.php?t=21714

[Martin]

we have been using Ned Wright's cosmology calculator here at SFN for over two years now.
it was one of the first things I posted about at beginning of this thread.

here is a writeup about the calculator
http://arxiv.org/abs/astro-ph/0609593
A Cosmology Calculator for the World Wide Web
Edward L. Wright (UCLA)
8 pages with 1 included figure. Cosmology calculator available at this http URL, light travel time converter at this http URL and the advanced cosmology calculator at this http URL

"A cosmology calculator that computes times and distances as a function of redshift for user-defined cosmological parameters is available on the World Wide Web. This note gives the formulae used by the cosmology calculator and discusses some of its implementation. A version of the calculator that allows one to specify the equation of state parameter w and w' and neutrino masses, and a version for converting the light travel times usually given in the popular press into redshifts are also available."

[Jacques]

It may interest some of you :

On Sunday, Nov. 19th, Earth will pass through a stream of debris from comet 55P/Tempel-Tuttle. The result: a shower of Leonid meteors.

"We expect an outburst of more than 100 Leonids per hour," says Bill Cooke, the head of NASA's Meteoroid Environment Office in Huntsville, AL.
http://science.nasa....nov_leonids.htm

[Martin]

http://www.uni.edu/m...ogy/cosmos.html

[Fred56]

Found a pretty nice EMR chart (nowhere else to put it):
http://www.lot-oriel...ight_deen01.pdf

Just for good measure, what a Mr Fradkin thinks we should be looking for:

http://online.kitp.u...adkin1_KITP.pdf

[Martin]

Updating some basic cosmology links:
Ned Wright's cosmology tutorial
http://www.astro.ucl...ht/cosmolog.htm

Ned Wright's cosmology FAQ
http://www.astro.ucl...mology_faq.html

Ned Wright's most basic cosmology calculator
http://www.astro.ucl.../CosmoCalc.html
(he has links to some more advanced or specialized calculators)

Morgan's calculator
http://www.uni.edu/m...ogy/cosmos.html

Murphy's coordinate conversion tool
http://fuse.pha.jhu....ls/eqtogal.html

Lineweaver and Davis' Scientific American article Misconceptions about the big bang March 2005.
AS LONG AS THIS PRINCETON LINK WORKS IT IS BETTER THAN THE OTHERS

http://www.astro.pri...ionsBigBang.pdf

Here are the links to the same article at the SciAm website. But these links have been going dead or else the GRAPHICS that you used to get have been disappearing. So these SciAm links may not be as good as the Princeton one

http://www.sciam.com...52383414B7F0147

The Lineweaver Davis article had some very useful SIDEBARS giving pictorial diagrams with a question together with right and wrong answers explained. For easier access, here are links to individual sidebars.

http://www.sciam.com...B7F0147_p39.gif
What kind of explosion was the big bang?

http://www.sciam.com...B7F0147_p40.gif
Can galaxies recede faster than light?

http://www.sciam.com...B7F0147_p42.gif
Can we see galaxies receding faster than light?

http://www.sciam.com...B7F0147_p43.gif
Why is there a cosmic redshift?

http://www.sciam.com...B7F0147_p44.gif
How large is the observable universe?

http://www.sciam.com...B7F0147_p45.gif
Do objects inside the universe expand, too?

[Martin]

Some recent cosmology data and estimates:
Komatsu et al (WMAP 5th year data, cosmology implications)
http://arxiv.org/abs/0803.0547

They publish a lowerbound estimate for the radius of curvature of the universe--95 percent confidence level.
See Figure 2 on page 4 and convert the units to lightyears
( 23 *(1/0.72)*3.26 billion lightyears = 104 billion lightyears )
A 'best fit' estimate derived from Ned Wright's January paper was 130 billion lightyears, not far from their lower bound.

So space might have infinite volume but it also might very well have finite. And if it has finite volume then they are telling us the length of the longest possible straight line is AT LEAST 2 pi times 104 billion lightyears-----in other words about 650 billion LY.

That's the idea of giving a lower bound. The circumference has to be at least 650 billion LY. It could be more, and it could be infinite, but with 95% confidence it cannot be less. If you could travel at a billion times c, then you could start out from earth and travel in the straightest possible line for at least 650 years before getting back to square one.

[Martin]

Nobel laureate George Smoot on observational cosmology, early universe, microwave background...
General audience, charts, graphs, but no equations.


http://www.revver.co...se-part-1-of-9/

http://www.revver.co...se-part-2-of-9/

http://www.revver.co...se-part-3-of-9/

http://www.revver.co...se-part-4-of-9/

http://www.revver.co...se-part-5-of-9/

http://www.revver.co...se-part-6-of-9/

http://www.revver.co...se-part-7-of-9/

http://www.revver.co...se-part-8-of-9/

http://www.revver.co...se-part-9-of-9/

[alex sam]

thank you for links

[zheng sheng ming]

it a good way! thanks!

[ExploreScience]

What a great list of resources.

I have been putting together a list of books, magazines, and news sources for people interested in astronomy and other fields in science and technology. The site is Explore-Science.net.

Great Astronomy Books is a growing list of the best reads in astronomy.

The Astronomy Magazines page presents the top picks for astronomy articles.

Finally, the Astronomy News section gathers the best sources on the web for astronomy discoveries and research.

[tika864]

thx so much this is very nice

[Klaynos]

!

Moderator Note

Summerwind's post about a new idea has been split and moved to speculations

http://www.sciencefo...nergy-proposal/