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 94300
Do you believe in UFOs? (Beginner) Apr 99 68212
Why are there no craters on Earth? Did all the meteorites miss us? (Beginner) Apr 99 111725
Can life exist on the recently discovered extrasolar planets? (Beginner) Apr 99 74552
How can two moons of Saturn share the same orbit? (Intermediate) Apr 99 94371
How do you measure the mass of a star? (Beginner) Apr 99 162431
What direction do planets rotate? (Beginner) Apr 99 410280
Can you hear sounds in space? (Beginner) Apr 99 606830
How can we measure distances to more stars? (Intermediate) Apr 99 70029
Where did all the water in the universe come from? (Intermediate) Apr 99 127612
Why doesn't gravity change the speed of light? (Beginner) Apr 99 64464
How can you tell the difference between single and multiple extrasolar planets? (Intermediate) Apr 99 50070
Do you think it's possible to maintain life on other planets? (Beginner) Apr 99 77490
When unmanned spacecraft accelerate in space, what causes them to slow down? (Intermediate) Apr 99 73955
What are Altitude and Azimuth? (Intermediate) Apr 99 151326
Do dead stars still shine? (Beginner) Apr 99 103771
How does light pollution affect astronomers? (Intermediate) Apr 99 154089
Have gravitational waves been proven to exist? (Intermediate) Apr 99 69131
What is a Dyson Sphere? (Intermediate) Apr 99 58846
Why do we not have eclipses every month? (Beginner) Mar 99 344897
Do astronomers believe in astrology? (Beginner) Mar 99 87488
Which planets have rings? (Beginner) Mar 99 575635
What equipment do I need for astrophotography? (Advanced) Mar 99 71500
How are photons created and destroyed? (Advanced) Mar 99 158940
Why search for only Earth-like life on other planets? (Beginner) Mar 99 61771
How do we know the mass of the Earth and the Moon? (Advanced) Mar 99 183256
Why is twilight short near the equator? (Intermediate) Mar 99 196415
What kind of telescope should I use for astrophotography? (Beginner) Mar 99 62171
Does the shuttle worry about space junk? (Beginner) Mar 99 56636
Why do stars change colour when they twinkle? (Beginner) Mar 99 202664
How can I contribute to science as an amateur astronomer? (Advanced) Mar 99 67949
Can the theory of formation of the solar system explain all the observables? (Intermediate) Mar 99 85265
What do stellar classifications mean? (Beginner) Mar 99 63185
Could we be seeing dead stars? (Beginner) Mar 99 71329
Can one star orbit another? (Beginner) Mar 99 66677
Why can't you see stars during the day? (Beginner) Mar 99 222944
What would happen if you took off your helmet in space? (Beginner) Mar 99 255988
What makes a satellite geosyncronise itself with Earth's orbit? (Intermediate) Mar 99 85596
Why is it important to study meteorites? (Beginner) Mar 99 98884
Why does the Moon look big on the horizon? (Intermediate) Mar 99 96885
When was the last time all of the planets were aligned? (Beginner) Mar 99 759206
How did asteroids form and what is the difference between an asteroid and a comet? (Beginner) Mar 99 131235
How do we measure distances to other stars? (Beginner) Mar 99 72553
What are the requirements for being a planet? (Beginner) Mar 99 326091
If comets are boiling away, why are there any left? (Intermediate) Mar 99 81647
What is sidereal time? (Beginner) Mar 99 83583
Which hemisphere has the best view of the Milky Way? (Beginner) Mar 99 121903
Why do all the planets orbit in the same plane? (Intermediate) Mar 99 409703
How are elements heavier than iron formed? (Intermediate) Feb 99 239018
Are time machines possible? (Intermediate) Jan 99 66238
Are the asteroids the remains of a planet which broke apart? (Beginner) Jan 99 74398
What is a nova? (Beginner) Jan 99 238893
Who first measured the speed of light? (Intermediate) Jan 99 179306
How do gravitons escape black holes to tell the universe about their gravity? (Advanced) Jan 99 128371
How do we know the age of the Universe and the Earth? (Intermediate) Jan 99 328268
What is that ring (or rainbow) around the moon? (Beginner) Jan 99 422813
How could galaxies have gotten so far away in only 14 billion years? (Intermediate) Jan 99 77274
Where are stars born? (Beginner) Jan 99 106026
Can you see satellites? (Beginner) Jan 99 101504
What kinds of star clusters are there? (Intermediate) Jan 99 60521
What is the life cycle of a star? (Intermediate) Jan 99 335684
How do I tell which planet is which? (Beginner) Jan 99 108079
Why do stars twinkle? (Beginner) Jan 99 569711
Can HST see the Oort cloud? (Intermediate) Jan 99 55298
What is the shape of the universe? (Intermediate) Jan 99 117668
How can geometry be different in space? (Intermediate) Jan 99 64217
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across? (Advanced) Jan 99 96261
Why are there blue shifted galaxies? (Intermediate) Jan 99 91492
What is a dimension? (Intermediate) Jan 99 87532
Will we get sucked into the black hole at the center of the Milky Way? (Beginner) Jan 99 125805
Can you tell time by the Big Dipper? (Beginner) Jan 99 62101
How powerful are quasars? (Intermediate) Jan 99 58357
What happens when you change the mass of a White Dwarf or Neutron Star? (Intermediate) Jan 99 82271
What caused Shoemaker-Levy 9 to split up? (Advanced) Jan 99 65204
How do we know if the universe will keep expanding forever? (Intermediate) Jan 99 127999
Why do planets not twinkle? (Intermediate) Jan 99 164285
Can we find the place where the Big Bang happened? (Intermediate) Jan 99 256354
What are the boundaries of the constellations? (Beginner) Jan 99 64589
Why is our solar system so different from all the others we've found? (Intermediate) Jan 99 93812
How do distant galaxies differ from those nearby? (Advanced) Jan 99 63453
How long does it take for the Sun's light to reach us? (Beginner) Jan 99 744471
Do electrons age? (Beginner) Jan 99 57480
What causes seasons? (Beginner) Jan 99 128939
What is time dilation? (Intermediate) Dec 98 111121

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