Class Notes (810,889)
Canada (494,324)
Astronomy (153)
ASTRON 2B03 (116)

Sep.27 - 2B03.docx

5 Pages
Unlock Document

McMaster University
Laura Parker

Sep. 27 – 2B03 27/09/2011 9:34:00 AM Modern definition of the metre.  Vs. the historic piece of metal sitting in France. Mass – piece of metal sitting in France.  Defined by. GRAVITY 4 fundamental forces of nature. Strength of gravity:  Strong enough to kee moon in orbit around earth  Keeps galaxies together o Balance between gravity of mass and motions of the stars. Gravity acts on short as well as really long ranges. Is it a strong force (relative to other forces?)  The Big Crunch idea -> possible scenario for outcome of the universe (not the favoured model).  It is strong - the big crunch has gravity at its base. Gravitational attraction between neighbour and I are small.  Force is too small. Other fundamental forces:  1) Strong force – only imp. on incredibly small scales o Keeping protons and neutrons in the nucleus -> keeps corks together. o *We are using strong force as our metric.  2) Electromagnetic force – o interaction of light w/ matter -> keeps atoms together o 100x less strong than Strong force. o Infinite range.  3) Weak force – main importance in nuclear decay (fission processes). o Only force imp. for neutrinos. o Pretty weak o Significantly weaker than Strong force.  IMP. forces for atoms & molecules.  4) Gravity – force of attraction of one amass on another
More Less

Related notes for ASTRON 2B03

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.