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 100509
Do you believe in UFOs? (Beginner) Apr 99 72159
Why are there no craters on Earth? Did all the meteorites miss us? (Beginner) Apr 99 117386
Can life exist on the recently discovered extrasolar planets? (Beginner) Apr 99 79015
How can two moons of Saturn share the same orbit? (Intermediate) Apr 99 98738
How do you measure the mass of a star? (Beginner) Apr 99 168742
What direction do planets rotate? (Beginner) Apr 99 424312
Can you hear sounds in space? (Beginner) Apr 99 615449
How can we measure distances to more stars? (Intermediate) Apr 99 73362
Where did all the water in the universe come from? (Intermediate) Apr 99 132629
Why doesn't gravity change the speed of light? (Beginner) Apr 99 68491
How can you tell the difference between single and multiple extrasolar planets? (Intermediate) Apr 99 52876
Do you think it's possible to maintain life on other planets? (Beginner) Apr 99 81036
When unmanned spacecraft accelerate in space, what causes them to slow down? (Intermediate) Apr 99 78100
What are Altitude and Azimuth? (Intermediate) Apr 99 155766
Do dead stars still shine? (Beginner) Apr 99 108630
How does light pollution affect astronomers? (Intermediate) Apr 99 159250
Have gravitational waves been proven to exist? (Intermediate) Apr 99 73266
What is a Dyson Sphere? (Intermediate) Apr 99 62119
Why do we not have eclipses every month? (Beginner) Mar 99 363859
Do astronomers believe in astrology? (Beginner) Mar 99 92690
Which planets have rings? (Beginner) Mar 99 580389
What equipment do I need for astrophotography? (Advanced) Mar 99 75247
How are photons created and destroyed? (Advanced) Mar 99 167771
Why search for only Earth-like life on other planets? (Beginner) Mar 99 65845
How do we know the mass of the Earth and the Moon? (Advanced) Mar 99 189907
Why is twilight short near the equator? (Intermediate) Mar 99 203990
What kind of telescope should I use for astrophotography? (Beginner) Mar 99 65346
Does the shuttle worry about space junk? (Beginner) Mar 99 59942
Why do stars change colour when they twinkle? (Beginner) Mar 99 211401
How can I contribute to science as an amateur astronomer? (Advanced) Mar 99 71029
Can the theory of formation of the solar system explain all the observables? (Intermediate) Mar 99 90776
What do stellar classifications mean? (Beginner) Mar 99 67234
Could we be seeing dead stars? (Beginner) Mar 99 76073
Can one star orbit another? (Beginner) Mar 99 69594
Why can't you see stars during the day? (Beginner) Mar 99 232562
What would happen if you took off your helmet in space? (Beginner) Mar 99 261231
What makes a satellite geosyncronise itself with Earth's orbit? (Intermediate) Mar 99 90179
Why is it important to study meteorites? (Beginner) Mar 99 103416
Why does the Moon look big on the horizon? (Intermediate) Mar 99 101069
When was the last time all of the planets were aligned? (Beginner) Mar 99 779329
How did asteroids form and what is the difference between an asteroid and a comet? (Beginner) Mar 99 136271
How do we measure distances to other stars? (Beginner) Mar 99 75961
What are the requirements for being a planet? (Beginner) Mar 99 338775
If comets are boiling away, why are there any left? (Intermediate) Mar 99 85174
What is sidereal time? (Beginner) Mar 99 87848
Which hemisphere has the best view of the Milky Way? (Beginner) Mar 99 126939
Why do all the planets orbit in the same plane? (Intermediate) Mar 99 422923
How are elements heavier than iron formed? (Intermediate) Feb 99 246537
Are time machines possible? (Intermediate) Jan 99 69388
Are the asteroids the remains of a planet which broke apart? (Beginner) Jan 99 77482
What is a nova? (Beginner) Jan 99 243989
Who first measured the speed of light? (Intermediate) Jan 99 185967
How do gravitons escape black holes to tell the universe about their gravity? (Advanced) Jan 99 133535
How do we know the age of the Universe and the Earth? (Intermediate) Jan 99 334535
What is that ring (or rainbow) around the moon? (Beginner) Jan 99 430248
How could galaxies have gotten so far away in only 14 billion years? (Intermediate) Jan 99 80797
Where are stars born? (Beginner) Jan 99 109753
Can you see satellites? (Beginner) Jan 99 105181
What kinds of star clusters are there? (Intermediate) Jan 99 63764
What is the life cycle of a star? (Intermediate) Jan 99 341573
How do I tell which planet is which? (Beginner) Jan 99 113498
Why do stars twinkle? (Beginner) Jan 99 575396
Can HST see the Oort cloud? (Intermediate) Jan 99 58010
What is the shape of the universe? (Intermediate) Jan 99 121802
How can geometry be different in space? (Intermediate) Jan 99 66819
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across? (Advanced) Jan 99 101320
Why are there blue shifted galaxies? (Intermediate) Jan 99 96348
What is a dimension? (Intermediate) Jan 99 91902
Will we get sucked into the black hole at the center of the Milky Way? (Beginner) Jan 99 130973
Can you tell time by the Big Dipper? (Beginner) Jan 99 65469
How powerful are quasars? (Intermediate) Jan 99 61087
What happens when you change the mass of a White Dwarf or Neutron Star? (Intermediate) Jan 99 86616
What caused Shoemaker-Levy 9 to split up? (Advanced) Jan 99 68218
How do we know if the universe will keep expanding forever? (Intermediate) Jan 99 132895
Why do planets not twinkle? (Intermediate) Jan 99 169721
Can we find the place where the Big Bang happened? (Intermediate) Jan 99 275404
What are the boundaries of the constellations? (Beginner) Jan 99 68806
Why is our solar system so different from all the others we've found? (Intermediate) Jan 99 98741
How do distant galaxies differ from those nearby? (Advanced) Jan 99 67043
How long does it take for the Sun's light to reach us? (Beginner) Jan 99 764305
Do electrons age? (Beginner) Jan 99 61498
What causes seasons? (Beginner) Jan 99 134381
What is time dilation? (Intermediate) Dec 98 115921

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