A&C reference library

turbo

http://www.sundog.clara.co.uk/halo/halosim.htm

The graphics are not hot-linked, but they are well-labeled, and the menus at the left will link you to further information.

marcus

Peter Dunsby's online course. special and general relativity
very basic for the most part
http://vishnu.mth.uct.ac.za/omei/gr/index.html

marcus

Here is a link with some physical data about Titan
http://library.thinkquest.org/18188/...oons/titan.htm
I will try to get some other links, just to confirm the numbers.
they say

mass 1.35E23 kilogram (2.259 percent of earth)
radius 2575 km
density 1.88
distance from Saturn 1,221,850 km
orbital period 15.945 days
surface temperature -178 celsius
surface pressure 1.6 bar (60 percent more pressure than earth)
escape velocity 2.65 km/second

this data is before Huygens and some of it might have already been improved on.
If anybody knows some better please post it. TIA.

Possibly the most reliable source is a JPL site I just found:
http://ssd.jpl.nasa.gov/sat_props.html
http://ssd.jpl.nasa.gov/sat_elem.html

Here is a sample---BTW they dont show mass in kilograms, they show GM (which is what astronomers measure, and then infer mass from it)

Titan
GM (km3/sec2) 8978.0 ± 0.8
Radius (km) 2575.5 ± 2.
Density (g/cm3) 1.880 ± 0.004

this site was updated as recently as November 2004
just for comparison here's what JPL NASA has for 4 jovians

Io
5959.916 ± 0.012
1821.6 ± 0.5
3.528 ± 0.006


Europa
3202.739 ± 0.009
1560.8 ± 0.5
3.013 ± 0.005


Ganymede
9887.834 ± 0.017
2631.2 ± 1.7
1.942 ± 0.005


Callisto
7179.289 ± 0.013
2410.3 ± 1.5
1.834 ± 0.004

Here's the main address
http://ssd.jpl.nasa.gov/

marcus

intriguing new technique for measuring the mass of a star
http://arxiv.org/abs/astro-ph/0501548

European Space Agency page of facts about Titan
http://www.esa.int/SPECIALS/Cassini-...F2HHZTD_0.html

wolram

http://xyz.lanl.gov/pdf/gr-qc/0501041
The basics of gravitational wave theory
47 pages jan 2005
Please discard this if it is of no use.

Physik

Orbital Mechanics Basics

This is a very cool site that explains Orbital Mechanics from the beginning, and explains all the math steps of the equations. (Unlike some other sites I've been to.)

http://www.braeunig.us/space/orbmech.htm

turbo

I have been plowing through the Vega lectures (including the wonderful Feynman series) and linked resources, and found that this man has linked streaming videos from academic programs all over the world. If you enjoy science, I know what you'll be doing for the next few months.

http://web.mit.edu/people/cabi/Links...nar_videos.htm

marcus

http://www.sciam.com/article.cfm?cha...2383414B7F0147

Popular written feature article "Misconceptions about BigBang"
Here are some sample "sidebars" of the article. Each has one or more visual diagrams with a wrong answer discussed and a right answer explained.


http://www.sciam.com/media/inline/00...7F0147_p39.gif
What kind of explosion was the big bang?

http://www.sciam.com/media/inline/00...7F0147_p40.gif
Can galaxies recede faster than light?

http://www.sciam.com/media/inline/00...7F0147_p42.gif
Can we see galaxies receding faster than light?

http://www.sciam.com/media/inline/00...7F0147_p43.gif
Why is there a cosmic redshift?

http://www.sciam.com/media/inline/00...7F0147_p44.gif
How large is the observable universe?

http://www.sciam.com/media/inline/00...7F0147_p45.gif
Do objects inside the universe expand, too?

marcus

a NASA resource for teachers called "ask a high energy astronomer"
http://imagine.gsfc.nasa.gov/docs/as...stronomer.html

when I sampled it I found a lot dated in the late 1990s, which can be fine.
lot of it was good information. some things I came across seemed questionable or outdated. worth keeping tabs on though

like this nasa page has a link to a list of "known black holes"
which gives some details about each of the one listed
http://imagine.gsfc.nasa.gov/docs/as...s/011120a.html

http://mintaka.sdsu.edu/faculty/orosz/web/

marcus

I like Thanu Padmanabhan, he is a worldclass relativist and cosmologist and he uses references to lewis carroll hunting of the snark
and generally manages to be deep and witty some of the time
and he also pulled the rug out from under string theory recently with his paper that says it is not enough for a theory to produce gravitons, that does not make it a quantum gravity theory
he had this paper From Gravitons to Gravity: Myths versus Reality

Well padmanabhhan has come out with one of these surveys of cosmology for general audience, that a senior cosmologist may do every now and then.
http://arxiv.org/abs/gr-qc/0503107
Understanding Our Universe: Current Status and Open Issues
T. Padmanabhan
To appear in "100 Years of Relativity - Space-time Structure: Einstein and Beyond", A.Ashtekar (Editor), World Scientific (Singapore, 2005); 30 pages; 4 figures

"Last couple of decades have been the golden age for cosmology. High quality data confirmed the broad paradigm of standard cosmology but have thrusted upon us a preposterous composition for the universe which defies any simple explanation, thereby posing probably the greatest challenge theoretical physics has ever faced. Several aspects of these developments are critically reviewed, concentrating on conceptual issues and open questions. [Topics discussed include: Cosmological Paradigm, Growth of structures in the universe, Inflation and generation of initial perturbations, Temperature anisotropies of the CMBR, Dark energy, Cosmological Constant, Deeper issues in cosmology.]"

turbo

WGBH forum with streaming video lectures on LOTS of subjects, including astronomy (under the science subject heading).

http://forum.wgbh.org/wgbh/

marcus

http://arxiv.org/abs/physics/0503245
Neutron Stars
Gordon Baym, Frederick K. Lamb
Comments: Encyclopedia of Physics 3rd ed., R.G. Lerner and G.L. Trigg, eds., Wiley-VCH, Berlin

Abstract: "This short encyclopedia article, reviewing current information on neutron stars, is intended for a broad scientific audience."

Only 3 pages, but has a lot of interesting facts about the topic


Also turbo supplied a link to a Feynman lecture audio on conservation of energy

http://home.hockaday.org/HockadayNet...h/FeynEng.html

cosmoboy

hi,
I woould like to suggest the following:

Review articles
1. Large scale structure of the universe and cosmological
perturbation theory (Bernardeau et al)
http://arxiv.org/abs/astro-ph/0112551
2. Cosmological Constant - the Weight of the Vacuum
( T. Padmanabhan)
http://arxiv.org/abs/hep-th/0212290
3. Lagrangian Perturbation and Other Approximations to Nolinear Gravitational Evolution
http://www.columbia.edu/~fms5/w161.html


Books
1.Particle Physics and Inflationary Cosmology
(Andrei Linde)
http://arxiv.org/abs/hep-th/0503203

marcus

this paper describes a possible test of GR using LISA
Clifford Will is a co-author
http://arxiv.org/abs/gr-qc/0504017

marcus

A FAQ is what does it mean that the old classical model of BH fails to compute at a certain point (has a "singularity") and gives non-physical answers or no answers at all.

What it means is a fault or limitation of the old classical Gen Rel theory. So now people are studying improved models of BH which dont have that failing. here are some people:

Abhay Ashtekar, Viqar Husain, Oliver Winkler, Leonardo Modesto, Martin Bojowald, Roy Maartens, Rituparno Goswami, Parampreet Singh.

Here are some recent research papers that they have written:

http://arxiv.org/abs/gr-qc/0504029
http://arxiv.org/abs/gr-qc/0503041
http://arxiv.org/abs/gr-qc/0504043
http://arxiv.org/abs/gr-qc/0411032
http://arxiv.org/abs/gr-qc/0407097
http://arxiv.org/abs/gr-qc/0412039
http://arxiv.org/abs/gr-qc/0410125

wolram

http://www.psychcentral.com/psypsych/Milky_Way

The Milky-way lots of links and info on our backyard.

cosmo_boy

Here you can find many interesting recent papers in
physics & astrophysics.

http://web.mit.edu/redingtn/www/netadv/welcome.html