Ask an Astronomer Team

Dave Kornreich

Dave was the founder of Ask an Astronomer. He got his PhD from Cornell in 2001 and is now an assistant professor in the Department of Physics and Physical Science at Humboldt State University in California. There he runs his own version of Ask the Astronomer. He also helps us out with the odd cosmology question.

Display # 
Title Created Date Hits
Why do most moons orbit their planets at the equator? (Intermediate) Apr 99 82332
Do you believe in UFOs? (Beginner) Apr 99 60432
Why are there no craters on Earth? Did all the meteorites miss us? (Beginner) Apr 99 98703
Can life exist on the recently discovered extrasolar planets? (Beginner) Apr 99 65928
How can two moons of Saturn share the same orbit? (Intermediate) Apr 99 86199
How do you measure the mass of a star? (Beginner) Apr 99 149845
What direction do planets rotate? (Beginner) Apr 99 370906
Can you hear sounds in space? (Beginner) Apr 99 580234
How can we measure distances to more stars? (Intermediate) Apr 99 62751
Where did all the water in the universe come from? (Intermediate) Apr 99 116564
Why doesn't gravity change the speed of light? (Beginner) Apr 99 58892
How can you tell the difference between single and multiple extrasolar planets? (Intermediate) Apr 99 44072
Do you think it's possible to maintain life on other planets? (Beginner) Apr 99 70923
When unmanned spacecraft accelerate in space, what causes them to slow down? (Intermediate) Apr 99 65226
What are Altitude and Azimuth? (Intermediate) Apr 99 141041
Do dead stars still shine? (Beginner) Apr 99 93412
How does light pollution affect astronomers? (Intermediate) Apr 99 140777
Have gravitational waves been proven to exist? (Intermediate) Apr 99 61334
What is a Dyson Sphere? (Intermediate) Apr 99 52600
Why do we not have eclipses every month? (Beginner) Mar 99 310934
Do astronomers believe in astrology? (Beginner) Mar 99 76093
Which planets have rings? (Beginner) Mar 99 562313
What equipment do I need for astrophotography? (Advanced) Mar 99 63667
How are photons created and destroyed? (Advanced) Mar 99 136949
Why search for only Earth-like life on other planets? (Beginner) Mar 99 54070
How do we know the mass of the Earth and the Moon? (Advanced) Mar 99 169379
Why is twilight short near the equator? (Intermediate) Mar 99 177684
What kind of telescope should I use for astrophotography? (Beginner) Mar 99 54874
Does the shuttle worry about space junk? (Beginner) Mar 99 49360
Why do stars change colour when they twinkle? (Beginner) Mar 99 179916
How can I contribute to science as an amateur astronomer? (Advanced) Mar 99 61164
Can the theory of formation of the solar system explain all the observables? (Intermediate) Mar 99 74119
What do stellar classifications mean? (Beginner) Mar 99 55088
Could we be seeing dead stars? (Beginner) Mar 99 61256
Can one star orbit another? (Beginner) Mar 99 60855
Why can't you see stars during the day? (Beginner) Mar 99 205825
What would happen if you took off your helmet in space? (Beginner) Mar 99 240331
What makes a satellite geosyncronise itself with Earth's orbit? (Intermediate) Mar 99 74647
Why is it important to study meteorites? (Beginner) Mar 99 89479
Why does the Moon look big on the horizon? (Intermediate) Mar 99 89307
When was the last time all of the planets were aligned? (Beginner) Mar 99 704862
How did asteroids form and what is the difference between an asteroid and a comet? (Beginner) Mar 99 121496
How do we measure distances to other stars? (Beginner) Mar 99 65482
What are the requirements for being a planet? (Beginner) Mar 99 297453
If comets are boiling away, why are there any left? (Intermediate) Mar 99 75047
What is sidereal time? (Beginner) Mar 99 74551
Which hemisphere has the best view of the Milky Way? (Beginner) Mar 99 111740
Why do all the planets orbit in the same plane? (Intermediate) Mar 99 371486
How are elements heavier than iron formed? (Intermediate) Feb 99 221626
Are time machines possible? (Intermediate) Jan 99 60143
Are the asteroids the remains of a planet which broke apart? (Beginner) Jan 99 66689
What is a nova? (Beginner) Jan 99 226772
Who first measured the speed of light? (Intermediate) Jan 99 165993
How do gravitons escape black holes to tell the universe about their gravity? (Advanced) Jan 99 116315
How do we know the age of the Universe and the Earth? (Intermediate) Jan 99 311616
What is that ring (or rainbow) around the moon? (Beginner) Jan 99 401030
How could galaxies have gotten so far away in only 14 billion years? (Intermediate) Jan 99 67786
Where are stars born? (Beginner) Jan 99 97624
Can you see satellites? (Beginner) Jan 99 91997
What kinds of star clusters are there? (Intermediate) Jan 99 53850
What is the life cycle of a star? (Intermediate) Jan 99 324077
How do I tell which planet is which? (Beginner) Jan 99 95427
Why do stars twinkle? (Beginner) Jan 99 550733
Can HST see the Oort cloud? (Intermediate) Jan 99 49098
What is the shape of the universe? (Intermediate) Jan 99 108534
How can geometry be different in space? (Intermediate) Jan 99 58457
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across? (Advanced) Jan 99 81135
Why are there blue shifted galaxies? (Intermediate) Jan 99 82409
What is a dimension? (Intermediate) Jan 99 79424
Will we get sucked into the black hole at the center of the Milky Way? (Beginner) Jan 99 116343
Can you tell time by the Big Dipper? (Beginner) Jan 99 55769
How powerful are quasars? (Intermediate) Jan 99 52646
What happens when you change the mass of a White Dwarf or Neutron Star? (Intermediate) Jan 99 73566
What caused Shoemaker-Levy 9 to split up? (Advanced) Jan 99 58869
How do we know if the universe will keep expanding forever? (Intermediate) Jan 99 116694
Why do planets not twinkle? (Intermediate) Jan 99 151162
Can we find the place where the Big Bang happened? (Intermediate) Jan 99 209020
What are the boundaries of the constellations? (Beginner) Jan 99 56165
Why is our solar system so different from all the others we've found? (Intermediate) Jan 99 84656
How do distant galaxies differ from those nearby? (Advanced) Jan 99 55843
How long does it take for the Sun's light to reach us? (Beginner) Jan 99 691223
Do electrons age? (Beginner) Jan 99 50535
What causes seasons? (Beginner) Jan 99 116288
What is time dilation? (Intermediate) Dec 98 100610

Most Popular

Our Reddit AMAs

AMA = Ask Me (Us) Anything