Expert: Jayendra Upadhye - 2/2/2005

Question
hey there, i need to know if these are true or false, if false, why?  Thanks

1) stars that began their lives with the most mass live longer then less massive stars because it takes them a lot longer to use up their hydrogen fuel

2) star clusters with lots of bright, blue stars are generally younger then clusters that don't have any such stars

3) all giants, supergiants, and white dwarfs were once main-sequence stars

4) time runs slightly slower on the surface of the sun that is does here on Earth

5) telescopes sometimes see multiple images of a single object, just as we should expect from the general theory of relativity

6) although there are 6 known types of quarks, ordinary atoms contain only 2 of these types

7) the exclusion principle applies to protons and neutrons as well as to electrons

Answer
Jono I hate classwork!
1 - False as Massive stars HAVE to spend fuel faster to maintain pressure balance against their higher gravity.
2 - True As presence of Bright Blue stars (lifetimes few million years, indicate youth. Absence of the same indicates all fusable hydrogen has been used up and the stars have moved into late middle age or terminal years.
3 - True Giants make it to the sequence in 2 million years, the sun like ones in 20 million years. Main sequence is the period of life of  star where hydrogen converts to helium.
4 - True as a clock in strong gravity runs slowly.
5 - True that is gravitational lensing.
6 - True! Ordinary matter has only the up and the down quark associated with it.
A proton contains two up quarks and one down quark, giving a total charge of +1. A neutron is made of two down quarks and one up quark, giving a total charge of zero. The other varieties of quarks can only be produced in particle accelerators, and decay quickly into the up and down quarks. (Electrons do not contain quarks, but are of a different type of particle called leptons).
ref:-http://en.wikipedia.org/wiki/Quarks
7 - True! ). In fact, we now know that that the Pauli exclusion principle holds for not just electrons but for any fermions (half-integer spin particles like electrons, protons, neutrons, muons, and many more.)
ref:- http://www.physlink.com/Education/AskExperts/ae455.cfm
Jayen