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 106437
Do you believe in UFOs? (Beginner) Apr 99 76104
Why are there no craters on Earth? Did all the meteorites miss us? (Beginner) Apr 99 122605
Can life exist on the recently discovered extrasolar planets? (Beginner) Apr 99 84830
How can two moons of Saturn share the same orbit? (Intermediate) Apr 99 102608
How do you measure the mass of a star? (Beginner) Apr 99 175203
What direction do planets rotate? (Beginner) Apr 99 438185
Can you hear sounds in space? (Beginner) Apr 99 622415
How can we measure distances to more stars? (Intermediate) Apr 99 77779
Where did all the water in the universe come from? (Intermediate) Apr 99 138167
Why doesn't gravity change the speed of light? (Beginner) Apr 99 71991
How can you tell the difference between single and multiple extrasolar planets? (Intermediate) Apr 99 55915
Do you think it's possible to maintain life on other planets? (Beginner) Apr 99 85576
When unmanned spacecraft accelerate in space, what causes them to slow down? (Intermediate) Apr 99 83034
What are Altitude and Azimuth? (Intermediate) Apr 99 160033
Do dead stars still shine? (Beginner) Apr 99 113839
How does light pollution affect astronomers? (Intermediate) Apr 99 164599
Have gravitational waves been proven to exist? (Intermediate) Apr 99 78209
What is a Dyson Sphere? (Intermediate) Apr 99 65681
Why do we not have eclipses every month? (Beginner) Mar 99 381048
Do astronomers believe in astrology? (Beginner) Mar 99 98589
Which planets have rings? (Beginner) Mar 99 584795
What equipment do I need for astrophotography? (Advanced) Mar 99 79274
How are photons created and destroyed? (Advanced) Mar 99 177165
Why search for only Earth-like life on other planets? (Beginner) Mar 99 70108
How do we know the mass of the Earth and the Moon? (Advanced) Mar 99 195276
Why is twilight short near the equator? (Intermediate) Mar 99 211833
What kind of telescope should I use for astrophotography? (Beginner) Mar 99 69294
Does the shuttle worry about space junk? (Beginner) Mar 99 63818
Why do stars change colour when they twinkle? (Beginner) Mar 99 220201
How can I contribute to science as an amateur astronomer? (Advanced) Mar 99 75379
Can the theory of formation of the solar system explain all the observables? (Intermediate) Mar 99 95692
What do stellar classifications mean? (Beginner) Mar 99 71524
Could we be seeing dead stars? (Beginner) Mar 99 81072
Can one star orbit another? (Beginner) Mar 99 73270
Why can't you see stars during the day? (Beginner) Mar 99 239763
What would happen if you took off your helmet in space? (Beginner) Mar 99 266359
What makes a satellite geosyncronise itself with Earth's orbit? (Intermediate) Mar 99 95558
Why is it important to study meteorites? (Beginner) Mar 99 107995
Why does the Moon look big on the horizon? (Intermediate) Mar 99 105007
When was the last time all of the planets were aligned? (Beginner) Mar 99 797111
How did asteroids form and what is the difference between an asteroid and a comet? (Beginner) Mar 99 141506
How do we measure distances to other stars? (Beginner) Mar 99 79814
What are the requirements for being a planet? (Beginner) Mar 99 349941
If comets are boiling away, why are there any left? (Intermediate) Mar 99 88893
What is sidereal time? (Beginner) Mar 99 93297
Which hemisphere has the best view of the Milky Way? (Beginner) Mar 99 132925
Why do all the planets orbit in the same plane? (Intermediate) Mar 99 435359
How are elements heavier than iron formed? (Intermediate) Feb 99 253730
Are time machines possible? (Intermediate) Jan 99 73013
Are the asteroids the remains of a planet which broke apart? (Beginner) Jan 99 81246
What is a nova? (Beginner) Jan 99 249582
Who first measured the speed of light? (Intermediate) Jan 99 193971
How do gravitons escape black holes to tell the universe about their gravity? (Advanced) Jan 99 138712
How do we know the age of the Universe and the Earth? (Intermediate) Jan 99 340464
What is that ring (or rainbow) around the moon? (Beginner) Jan 99 439906
How could galaxies have gotten so far away in only 14 billion years? (Intermediate) Jan 99 85391
Where are stars born? (Beginner) Jan 99 114154
Can you see satellites? (Beginner) Jan 99 109723
What kinds of star clusters are there? (Intermediate) Jan 99 67760
What is the life cycle of a star? (Intermediate) Jan 99 348120
How do I tell which planet is which? (Beginner) Jan 99 119633
Why do stars twinkle? (Beginner) Jan 99 580694
Can HST see the Oort cloud? (Intermediate) Jan 99 61565
What is the shape of the universe? (Intermediate) Jan 99 126582
How can geometry be different in space? (Intermediate) Jan 99 69737
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across? (Advanced) Jan 99 106650
Why are there blue shifted galaxies? (Intermediate) Jan 99 101599
What is a dimension? (Intermediate) Jan 99 96794
Will we get sucked into the black hole at the center of the Milky Way? (Beginner) Jan 99 136270
Can you tell time by the Big Dipper? (Beginner) Jan 99 68916
How powerful are quasars? (Intermediate) Jan 99 64577
What happens when you change the mass of a White Dwarf or Neutron Star? (Intermediate) Jan 99 90752
What caused Shoemaker-Levy 9 to split up? (Advanced) Jan 99 71613
How do we know if the universe will keep expanding forever? (Intermediate) Jan 99 138264
Why do planets not twinkle? (Intermediate) Jan 99 175465
Can we find the place where the Big Bang happened? (Intermediate) Jan 99 294113
What are the boundaries of the constellations? (Beginner) Jan 99 73126
Why is our solar system so different from all the others we've found? (Intermediate) Jan 99 104286
How do distant galaxies differ from those nearby? (Advanced) Jan 99 71287
How long does it take for the Sun's light to reach us? (Beginner) Jan 99 782649
Do electrons age? (Beginner) Jan 99 65731
What causes seasons? (Beginner) Jan 99 139936
What is time dilation? (Intermediate) Dec 98 121282

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