5,502 reputation
1632
bio website keith-s-thompson.github.com
location San Diego, CA
age 55
visits member for 3 years, 7 months
seen May 8 at 14:20

I'm a programmer and all-around nerd living in San Diego, California.
I work at JetHead Development Inc.

E-mail: Keith.S.Thompson@gmail.com


Nov
12
comment Why is this radio telescope's reflector spherical and not parabolic?
A paraboloid would probably be better if the telescope were aimed only in one direction, straight up. Most radio telescopes steer by moving the entire dish until the axis and receiver are aligned directly with the target. But Arecibo's dish is immovable, and to aim at targets off the vertical, only the receiver is moved. A spherical shape gives uniform reception over the entire range to which it can point. (A 1000-foot steerable dish would probably be a paraboloid.)
Nov
9
comment Difference between baryonic, inertial and gravitational mass? (and relation to dark matter)
@FlorinAndrei: Isn't that pretty much what "matter" means?
Nov
3
comment 2012: Is there some astronomical event happening?
And I just posted a small correction (not relevant to the current point) on your blog post.
Nov
2
answered Does the rotation of the earth dramatically affect airplane flight time?
Nov
2
awarded  Excavator
Nov
2
revised Age of the Earth and the star that preceded the Sun
Fix typo,capitalize Sun and Earth
Nov
2
suggested approved edit on Age of the Earth and the star that preceded the Sun
Oct
31
comment Does the rotation of the earth dramatically affect airplane flight time?
During the flight, you need to get up to use the restroom. There's one 10 rows in front of you, and another 10 rows behind you. Does it take longer to walk to the one that's moving away from you at 600 mph than the one that's moving towards you at 600 mph?
Oct
30
comment Why does an octave on a piano have the divisions of 8 white keys and 5 black keys?
Thanks for the detailed clarification.
Oct
30
awarded  Teacher
Oct
29
answered Why does an octave on a piano have the divisions of 8 white keys and 5 black keys?
Oct
28
comment Does $E$ really equal $mc^2$?
Doesn't $E = m c^2$ still apply if $m$ is taken to be the relativistic mass (which increases with increasing speed)?
Oct
28
comment How does the view of night sky change as the Sun orbits around the Milky Way?
Note that some of the apparent motions of the stars, particularly having to do with which star is currently the pole star, are affected by the precession of the equinoxes.
Oct
27
comment Does $E$ really equal $mc^2$?
@DavidZaslavsky: Then perhaps this is a good chance for them to learn. (I've updated the answer for, I hope, better clarity.)
Oct
27
awarded  Editor
Oct
27
revised Does $E$ really equal $mc^2$?
Clarification
Oct
27
comment Does $E$ really equal $mc^2$?
I was referring to the meaning of if-then in logic. See here.
Oct
26
answered Does $E$ really equal $mc^2$?
Oct
26
answered Why is this radio telescope's reflector spherical and not parabolic?
Oct
17
comment Is dark matter around the Milky Way spread in a spiral shape (or, in a different shape)?
Does that mean that spiral galaxies are disk shaped (as opposed to spherical) because of non-gravitational interactions? Wouldn't a spinning mass of gas and dust form a disk even without self-interaction?