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 75961
Do you believe in UFOs? (Beginner) Apr 99 56478
Why are there no craters on Earth? Did all the meteorites miss us? (Beginner) Apr 99 87512
Can life exist on the recently discovered extrasolar planets? (Beginner) Apr 99 61862
How can two moons of Saturn share the same orbit? (Intermediate) Apr 99 81021
How do you measure the mass of a star? (Beginner) Apr 99 139783
What direction do planets rotate? (Beginner) Apr 99 338040
Can you hear sounds in space? (Beginner) Apr 99 556778
How can we measure distances to more stars? (Intermediate) Apr 99 58360
Where did all the water in the universe come from? (Intermediate) Apr 99 107471
Why doesn't gravity change the speed of light? (Beginner) Apr 99 55809
How can you tell the difference between single and multiple extrasolar planets? (Intermediate) Apr 99 40213
Do you think it's possible to maintain life on other planets? (Beginner) Apr 99 67232
When unmanned spacecraft accelerate in space, what causes them to slow down? (Intermediate) Apr 99 59188
What are Altitude and Azimuth? (Intermediate) Apr 99 131086
Do dead stars still shine? (Beginner) Apr 99 87656
How does light pollution affect astronomers? (Intermediate) Apr 99 131849
Have gravitational waves been proven to exist? (Intermediate) Apr 99 56199
What is a Dyson Sphere? (Intermediate) Apr 99 49397
Why do we not have eclipses every month? (Beginner) Mar 99 282236
Do astronomers believe in astrology? (Beginner) Mar 99 70091
Which planets have rings? (Beginner) Mar 99 537743
What equipment do I need for astrophotography? (Advanced) Mar 99 59470
How are photons created and destroyed? (Advanced) Mar 99 122580
Why search for only Earth-like life on other planets? (Beginner) Mar 99 50106
How do we know the mass of the Earth and the Moon? (Advanced) Mar 99 157601
Why is twilight short near the equator? (Intermediate) Mar 99 157409
What kind of telescope should I use for astrophotography? (Beginner) Mar 99 51111
Does the shuttle worry about space junk? (Beginner) Mar 99 45824
Why do stars change colour when they twinkle? (Beginner) Mar 99 165872
How can I contribute to science as an amateur astronomer? (Advanced) Mar 99 56616
Can the theory of formation of the solar system explain all the observables? (Intermediate) Mar 99 66941
What do stellar classifications mean? (Beginner) Mar 99 50635
Could we be seeing dead stars? (Beginner) Mar 99 56227
Can one star orbit another? (Beginner) Mar 99 57521
Why can't you see stars during the day? (Beginner) Mar 99 187259
What would happen if you took off your helmet in space? (Beginner) Mar 99 221100
What makes a satellite geosyncronise itself with Earth's orbit? (Intermediate) Mar 99 65890
Why is it important to study meteorites? (Beginner) Mar 99 81362
Why does the Moon look big on the horizon? (Intermediate) Mar 99 85140
When was the last time all of the planets were aligned? (Beginner) Mar 99 655990
How did asteroids form and what is the difference between an asteroid and a comet? (Beginner) Mar 99 114501
How do we measure distances to other stars? (Beginner) Mar 99 61419
What are the requirements for being a planet? (Beginner) Mar 99 253149
If comets are boiling away, why are there any left? (Intermediate) Mar 99 70760
What is sidereal time? (Beginner) Mar 99 66813
Which hemisphere has the best view of the Milky Way? (Beginner) Mar 99 104752
Why do all the planets orbit in the same plane? (Intermediate) Mar 99 340564
How are elements heavier than iron formed? (Intermediate) Feb 99 202232
Are time machines possible? (Intermediate) Jan 99 56957
Are the asteroids the remains of a planet which broke apart? (Beginner) Jan 99 61252
What is a nova? (Beginner) Jan 99 215020
Who first measured the speed of light? (Intermediate) Jan 99 157827
How do gravitons escape black holes to tell the universe about their gravity? (Advanced) Jan 99 107204
How do we know the age of the Universe and the Earth? (Intermediate) Jan 99 298171
What is that ring (or rainbow) around the moon? (Beginner) Jan 99 384997
How could galaxies have gotten so far away in only 14 billion years? (Intermediate) Jan 99 62148
Where are stars born? (Beginner) Jan 99 92693
Can you see satellites? (Beginner) Jan 99 86556
What kinds of star clusters are there? (Intermediate) Jan 99 49450
What is the life cycle of a star? (Intermediate) Jan 99 314447
How do I tell which planet is which? (Beginner) Jan 99 84795
Why do stars twinkle? (Beginner) Jan 99 502564
Can HST see the Oort cloud? (Intermediate) Jan 99 45347
What is the shape of the universe? (Intermediate) Jan 99 102494
How can geometry be different in space? (Intermediate) Jan 99 55005
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across? (Advanced) Jan 99 75849
Why are there blue shifted galaxies? (Intermediate) Jan 99 77032
What is a dimension? (Intermediate) Jan 99 74130
Will we get sucked into the black hole at the center of the Milky Way? (Beginner) Jan 99 108342
Can you tell time by the Big Dipper? (Beginner) Jan 99 51905
How powerful are quasars? (Intermediate) Jan 99 49359
What happens when you change the mass of a White Dwarf or Neutron Star? (Intermediate) Jan 99 68633
What caused Shoemaker-Levy 9 to split up? (Advanced) Jan 99 54602
How do we know if the universe will keep expanding forever? (Intermediate) Jan 99 105686
Why do planets not twinkle? (Intermediate) Jan 99 140674
Can we find the place where the Big Bang happened? (Intermediate) Jan 99 174825
What are the boundaries of the constellations? (Beginner) Jan 99 51598
Why is our solar system so different from all the others we've found? (Intermediate) Jan 99 78134
How do distant galaxies differ from those nearby? (Advanced) Jan 99 51313
How long does it take for the Sun's light to reach us? (Beginner) Jan 99 662677
Do electrons age? (Beginner) Jan 99 47075
What causes seasons? (Beginner) Jan 99 108306
What is time dilation? (Intermediate) Dec 98 92725

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