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 72642
Do you believe in UFOs? (Beginner) Apr 99 54277
Why are there no craters on Earth? Did all the meteorites miss us? (Beginner) Apr 99 80872
Can life exist on the recently discovered extrasolar planets? (Beginner) Apr 99 59509
How can two moons of Saturn share the same orbit? (Intermediate) Apr 99 78248
How do you measure the mass of a star? (Beginner) Apr 99 132440
What direction do planets rotate? (Beginner) Apr 99 319282
Can you hear sounds in space? (Beginner) Apr 99 541955
How can we measure distances to more stars? (Intermediate) Apr 99 55875
Where did all the water in the universe come from? (Intermediate) Apr 99 102779
Why doesn't gravity change the speed of light? (Beginner) Apr 99 53837
How can you tell the difference between single and multiple extrasolar planets? (Intermediate) Apr 99 38436
Do you think it's possible to maintain life on other planets? (Beginner) Apr 99 65116
When unmanned spacecraft accelerate in space, what causes them to slow down? (Intermediate) Apr 99 56157
What are Altitude and Azimuth? (Intermediate) Apr 99 125128
Do dead stars still shine? (Beginner) Apr 99 83859
How does light pollution affect astronomers? (Intermediate) Apr 99 126506
Have gravitational waves been proven to exist? (Intermediate) Apr 99 53646
What is a Dyson Sphere? (Intermediate) Apr 99 47516
Why do we not have eclipses every month? (Beginner) Mar 99 266354
Do astronomers believe in astrology? (Beginner) Mar 99 66901
Which planets have rings? (Beginner) Mar 99 511689
What equipment do I need for astrophotography? (Advanced) Mar 99 57091
How are photons created and destroyed? (Advanced) Mar 99 114921
Why search for only Earth-like life on other planets? (Beginner) Mar 99 47989
How do we know the mass of the Earth and the Moon? (Advanced) Mar 99 151541
Why is twilight short near the equator? (Intermediate) Mar 99 148789
What kind of telescope should I use for astrophotography? (Beginner) Mar 99 49097
Does the shuttle worry about space junk? (Beginner) Mar 99 43724
Why do stars change colour when they twinkle? (Beginner) Mar 99 158188
How can I contribute to science as an amateur astronomer? (Advanced) Mar 99 54001
Can the theory of formation of the solar system explain all the observables? (Intermediate) Mar 99 63842
What do stellar classifications mean? (Beginner) Mar 99 47943
Could we be seeing dead stars? (Beginner) Mar 99 53719
Can one star orbit another? (Beginner) Mar 99 55462
Why can't you see stars during the day? (Beginner) Mar 99 176906
What would happen if you took off your helmet in space? (Beginner) Mar 99 201487
What makes a satellite geosyncronise itself with Earth's orbit? (Intermediate) Mar 99 62283
Why is it important to study meteorites? (Beginner) Mar 99 76736
Why does the Moon look big on the horizon? (Intermediate) Mar 99 82948
When was the last time all of the planets were aligned? (Beginner) Mar 99 624662
How did asteroids form and what is the difference between an asteroid and a comet? (Beginner) Mar 99 110924
How do we measure distances to other stars? (Beginner) Mar 99 59006
What are the requirements for being a planet? (Beginner) Mar 99 231645
If comets are boiling away, why are there any left? (Intermediate) Mar 99 68340
What is sidereal time? (Beginner) Mar 99 62519
Which hemisphere has the best view of the Milky Way? (Beginner) Mar 99 101020
Why do all the planets orbit in the same plane? (Intermediate) Mar 99 323993
How are elements heavier than iron formed? (Intermediate) Feb 99 194158
Are time machines possible? (Intermediate) Jan 99 55128
Are the asteroids the remains of a planet which broke apart? (Beginner) Jan 99 58476
What is a nova? (Beginner) Jan 99 208938
Who first measured the speed of light? (Intermediate) Jan 99 153537
How do gravitons escape black holes to tell the universe about their gravity? (Advanced) Jan 99 101772
How do we know the age of the Universe and the Earth? (Intermediate) Jan 99 292379
What is that ring (or rainbow) around the moon? (Beginner) Jan 99 374285
How could galaxies have gotten so far away in only 14 billion years? (Intermediate) Jan 99 59190
Where are stars born? (Beginner) Jan 99 89967
Can you see satellites? (Beginner) Jan 99 83935
What kinds of star clusters are there? (Intermediate) Jan 99 47171
What is the life cycle of a star? (Intermediate) Jan 99 308787
How do I tell which planet is which? (Beginner) Jan 99 80487
Why do stars twinkle? (Beginner) Jan 99 476288
Can HST see the Oort cloud? (Intermediate) Jan 99 43259
What is the shape of the universe? (Intermediate) Jan 99 99411
How can geometry be different in space? (Intermediate) Jan 99 53008
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across? (Advanced) Jan 99 73261
Why are there blue shifted galaxies? (Intermediate) Jan 99 74103
What is a dimension? (Intermediate) Jan 99 71263
Will we get sucked into the black hole at the center of the Milky Way? (Beginner) Jan 99 102471
Can you tell time by the Big Dipper? (Beginner) Jan 99 49555
How powerful are quasars? (Intermediate) Jan 99 47428
What happens when you change the mass of a White Dwarf or Neutron Star? (Intermediate) Jan 99 65547
What caused Shoemaker-Levy 9 to split up? (Advanced) Jan 99 51969
How do we know if the universe will keep expanding forever? (Intermediate) Jan 99 100533
Why do planets not twinkle? (Intermediate) Jan 99 134702
Can we find the place where the Big Bang happened? (Intermediate) Jan 99 161880
What are the boundaries of the constellations? (Beginner) Jan 99 49179
Why is our solar system so different from all the others we've found? (Intermediate) Jan 99 75075
How do distant galaxies differ from those nearby? (Advanced) Jan 99 48565
How long does it take for the Sun's light to reach us? (Beginner) Jan 99 644394
Do electrons age? (Beginner) Jan 99 45099
What causes seasons? (Beginner) Jan 99 104246
What is time dilation? (Intermediate) Dec 98 88754

Most Popular

Our Reddit AMAs

AMA = Ask Me (Us) Anything