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 90883
Do you believe in UFOs? (Beginner) Apr 99 66470
Why are there no craters on Earth? Did all the meteorites miss us? (Beginner) Apr 99 108661
Can life exist on the recently discovered extrasolar planets? (Beginner) Apr 99 72483
How can two moons of Saturn share the same orbit? (Intermediate) Apr 99 92510
How do you measure the mass of a star? (Beginner) Apr 99 159416
What direction do planets rotate? (Beginner) Apr 99 401941
Can you hear sounds in space? (Beginner) Apr 99 602062
How can we measure distances to more stars? (Intermediate) Apr 99 68504
Where did all the water in the universe come from? (Intermediate) Apr 99 125213
Why doesn't gravity change the speed of light? (Beginner) Apr 99 63135
How can you tell the difference between single and multiple extrasolar planets? (Intermediate) Apr 99 48573
Do you think it's possible to maintain life on other planets? (Beginner) Apr 99 75957
When unmanned spacecraft accelerate in space, what causes them to slow down? (Intermediate) Apr 99 71891
What are Altitude and Azimuth? (Intermediate) Apr 99 149290
Do dead stars still shine? (Beginner) Apr 99 101001
How does light pollution affect astronomers? (Intermediate) Apr 99 150555
Have gravitational waves been proven to exist? (Intermediate) Apr 99 67529
What is a Dyson Sphere? (Intermediate) Apr 99 57277
Why do we not have eclipses every month? (Beginner) Mar 99 336751
Do astronomers believe in astrology? (Beginner) Mar 99 84879
Which planets have rings? (Beginner) Mar 99 573520
What equipment do I need for astrophotography? (Advanced) Mar 99 69534
How are photons created and destroyed? (Advanced) Mar 99 154413
Why search for only Earth-like life on other planets? (Beginner) Mar 99 59758
How do we know the mass of the Earth and the Moon? (Advanced) Mar 99 179915
Why is twilight short near the equator? (Intermediate) Mar 99 192771
What kind of telescope should I use for astrophotography? (Beginner) Mar 99 60493
Does the shuttle worry about space junk? (Beginner) Mar 99 54968
Why do stars change colour when they twinkle? (Beginner) Mar 99 197740
How can I contribute to science as an amateur astronomer? (Advanced) Mar 99 66227
Can the theory of formation of the solar system explain all the observables? (Intermediate) Mar 99 82754
What do stellar classifications mean? (Beginner) Mar 99 61176
Could we be seeing dead stars? (Beginner) Mar 99 69107
Can one star orbit another? (Beginner) Mar 99 65382
Why can't you see stars during the day? (Beginner) Mar 99 219557
What would happen if you took off your helmet in space? (Beginner) Mar 99 253133
What makes a satellite geosyncronise itself with Earth's orbit? (Intermediate) Mar 99 83424
Why is it important to study meteorites? (Beginner) Mar 99 96896
Why does the Moon look big on the horizon? (Intermediate) Mar 99 95137
When was the last time all of the planets were aligned? (Beginner) Mar 99 750607
How did asteroids form and what is the difference between an asteroid and a comet? (Beginner) Mar 99 128687
How do we measure distances to other stars? (Beginner) Mar 99 70900
What are the requirements for being a planet? (Beginner) Mar 99 320365
If comets are boiling away, why are there any left? (Intermediate) Mar 99 80099
What is sidereal time? (Beginner) Mar 99 81617
Which hemisphere has the best view of the Milky Way? (Beginner) Mar 99 119706
Why do all the planets orbit in the same plane? (Intermediate) Mar 99 402170
How are elements heavier than iron formed? (Intermediate) Feb 99 235927
Are time machines possible? (Intermediate) Jan 99 64844
Are the asteroids the remains of a planet which broke apart? (Beginner) Jan 99 72753
What is a nova? (Beginner) Jan 99 236318
Who first measured the speed of light? (Intermediate) Jan 99 175556
How do gravitons escape black holes to tell the universe about their gravity? (Advanced) Jan 99 126031
How do we know the age of the Universe and the Earth? (Intermediate) Jan 99 324566
What is that ring (or rainbow) around the moon? (Beginner) Jan 99 417826
How could galaxies have gotten so far away in only 14 billion years? (Intermediate) Jan 99 75418
Where are stars born? (Beginner) Jan 99 104174
Can you see satellites? (Beginner) Jan 99 99734
What kinds of star clusters are there? (Intermediate) Jan 99 59088
What is the life cycle of a star? (Intermediate) Jan 99 333127
How do I tell which planet is which? (Beginner) Jan 99 105274
Why do stars twinkle? (Beginner) Jan 99 566795
Can HST see the Oort cloud? (Intermediate) Jan 99 53876
What is the shape of the universe? (Intermediate) Jan 99 115537
How can geometry be different in space? (Intermediate) Jan 99 62924
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across? (Advanced) Jan 99 93298
Why are there blue shifted galaxies? (Intermediate) Jan 99 89529
What is a dimension? (Intermediate) Jan 99 85628
Will we get sucked into the black hole at the center of the Milky Way? (Beginner) Jan 99 123492
Can you tell time by the Big Dipper? (Beginner) Jan 99 60767
How powerful are quasars? (Intermediate) Jan 99 57103
What happens when you change the mass of a White Dwarf or Neutron Star? (Intermediate) Jan 99 80009
What caused Shoemaker-Levy 9 to split up? (Advanced) Jan 99 63908
How do we know if the universe will keep expanding forever? (Intermediate) Jan 99 124624
Why do planets not twinkle? (Intermediate) Jan 99 161682
Can we find the place where the Big Bang happened? (Intermediate) Jan 99 247512
What are the boundaries of the constellations? (Beginner) Jan 99 62401
Why is our solar system so different from all the others we've found? (Intermediate) Jan 99 91601
How do distant galaxies differ from those nearby? (Advanced) Jan 99 61791
How long does it take for the Sun's light to reach us? (Beginner) Jan 99 735066
Do electrons age? (Beginner) Jan 99 56028
What causes seasons? (Beginner) Jan 99 126460
What is time dilation? (Intermediate) Dec 98 108984

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