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A start

Posted Jul24-08 at 10:50 AM by ubingc

Hello Everyone:

Just want to say a few words about me and what I am doing. I have been teaching both math and science at the community college level for 14 years now, and still feel like I am still learning both in my field and how to communicate it to my students.

My current interests are using computer algebra systems to help visualize the behavior of physical and mathematical systems. I am currently working with Maple 11, and see some great potential to help people...
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Old

well this my Hello to the blog world!!!!!!

Posted Jul24-08 at 07:30 AM by kancharlahare

hmm... well this my first blog and i am all excited about for it start on the physics forum site........
so well i donot what they write on a blog?
so let me make this a place to ask a few questions.
i am all confused with the concept of null energy..
well it says that no at 0 k no body can have complete ceasation(donot know whether the word exsists,hope you get the meaning.. everything stops) of energy... because the uncertainity principle doesn't allow that.
...
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Old

Dark energy 3

Posted Jul24-08 at 12:41 AM by stevebd1
Updated Aug16-08 at 07:26 AM by stevebd1

(continue from Part 2)

-Speed of light (c)- 299,792,458 m/s ≈ 3x10^8 m/s

-The Hubble constant (H)- 70 km/s/Mpc
The rate at which the velocity of recession of galaxies increases with distance from us (for every megaparsec (3,261,630 Lys) an object will increase by 70 km s^-1 in velocity) according to the Hubble law. The law proposed by Edwin Hubble in 1929 claiming a linear relation between the distance (r) of galaxies from us and their velocity of recession...
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Dark energy 2

Posted Jul24-08 at 12:40 AM by stevebd1
Updated Aug1-08 at 04:55 PM by stevebd1

(continued from Part 1)

The density of the observed 'luminous' matter in the universe is estimated by looking at a volume of space, working out the mass occupied by stars, nebula, free hydrogen and helium and dividing this by the volume, giving a density in the region of 0.040x10^-26 kg/m^3 (approx. 4.5% of the critical density).

This gave rise to the question 'if the universe is flat, where's the other mass that makes up the critical density?' A figure of 95% for
...
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Dark energy 1

Posted Jul24-08 at 12:40 AM by stevebd1
Updated Sep1-08 at 01:42 AM by stevebd1

The following is my own approach to understanding dark energy that I put together about 18 months ago.

Some sort of gravitationally repulsive material that permeates all of space and is currently increasing the rate of expansion of the universe. Discovered in 1998 while observing the luminosity of type 1a supernovae at various redshifts, it is very homogeneous, not very dense and is not known to interact through any of the fundamental forces other than gravity. It does not cluster...
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