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 85879
Do you believe in UFOs? (Beginner) Apr 99 62815
Why are there no craters on Earth? Did all the meteorites miss us? (Beginner) Apr 99 103570
Can life exist on the recently discovered extrasolar planets? (Beginner) Apr 99 68424
How can two moons of Saturn share the same orbit? (Intermediate) Apr 99 88767
How do you measure the mass of a star? (Beginner) Apr 99 154244
What direction do planets rotate? (Beginner) Apr 99 386774
Can you hear sounds in space? (Beginner) Apr 99 593049
How can we measure distances to more stars? (Intermediate) Apr 99 65002
Where did all the water in the universe come from? (Intermediate) Apr 99 120293
Why doesn't gravity change the speed of light? (Beginner) Apr 99 60473
How can you tell the difference between single and multiple extrasolar planets? (Intermediate) Apr 99 45678
Do you think it's possible to maintain life on other planets? (Beginner) Apr 99 72838
When unmanned spacecraft accelerate in space, what causes them to slow down? (Intermediate) Apr 99 68004
What are Altitude and Azimuth? (Intermediate) Apr 99 145065
Do dead stars still shine? (Beginner) Apr 99 96456
How does light pollution affect astronomers? (Intermediate) Apr 99 144994
Have gravitational waves been proven to exist? (Intermediate) Apr 99 63778
What is a Dyson Sphere? (Intermediate) Apr 99 54278
Why do we not have eclipses every month? (Beginner) Mar 99 322916
Do astronomers believe in astrology? (Beginner) Mar 99 79621
Which planets have rings? (Beginner) Mar 99 568481
What equipment do I need for astrophotography? (Advanced) Mar 99 65997
How are photons created and destroyed? (Advanced) Mar 99 145847
Why search for only Earth-like life on other planets? (Beginner) Mar 99 56204
How do we know the mass of the Earth and the Moon? (Advanced) Mar 99 174244
Why is twilight short near the equator? (Intermediate) Mar 99 184740
What kind of telescope should I use for astrophotography? (Beginner) Mar 99 57051
Does the shuttle worry about space junk? (Beginner) Mar 99 51431
Why do stars change colour when they twinkle? (Beginner) Mar 99 188939
How can I contribute to science as an amateur astronomer? (Advanced) Mar 99 63233
Can the theory of formation of the solar system explain all the observables? (Intermediate) Mar 99 77151
What do stellar classifications mean? (Beginner) Mar 99 57461
Could we be seeing dead stars? (Beginner) Mar 99 64227
Can one star orbit another? (Beginner) Mar 99 62575
Why can't you see stars during the day? (Beginner) Mar 99 213139
What would happen if you took off your helmet in space? (Beginner) Mar 99 246989
What makes a satellite geosyncronise itself with Earth's orbit? (Intermediate) Mar 99 78374
Why is it important to study meteorites? (Beginner) Mar 99 92807
Why does the Moon look big on the horizon? (Intermediate) Mar 99 91632
When was the last time all of the planets were aligned? (Beginner) Mar 99 727325
How did asteroids form and what is the difference between an asteroid and a comet? (Beginner) Mar 99 124404
How do we measure distances to other stars? (Beginner) Mar 99 67698
What are the requirements for being a planet? (Beginner) Mar 99 309828
If comets are boiling away, why are there any left? (Intermediate) Mar 99 76961
What is sidereal time? (Beginner) Mar 99 77539
Which hemisphere has the best view of the Milky Way? (Beginner) Mar 99 115075
Why do all the planets orbit in the same plane? (Intermediate) Mar 99 386516
How are elements heavier than iron formed? (Intermediate) Feb 99 228824
Are time machines possible? (Intermediate) Jan 99 61917
Are the asteroids the remains of a planet which broke apart? (Beginner) Jan 99 69443
What is a nova? (Beginner) Jan 99 231384
Who first measured the speed of light? (Intermediate) Jan 99 169244
How do gravitons escape black holes to tell the universe about their gravity? (Advanced) Jan 99 120280
How do we know the age of the Universe and the Earth? (Intermediate) Jan 99 317349
What is that ring (or rainbow) around the moon? (Beginner) Jan 99 409565
How could galaxies have gotten so far away in only 14 billion years? (Intermediate) Jan 99 70911
Where are stars born? (Beginner) Jan 99 100312
Can you see satellites? (Beginner) Jan 99 95174
What kinds of star clusters are there? (Intermediate) Jan 99 55895
What is the life cycle of a star? (Intermediate) Jan 99 328220
How do I tell which planet is which? (Beginner) Jan 99 100107
Why do stars twinkle? (Beginner) Jan 99 560124
Can HST see the Oort cloud? (Intermediate) Jan 99 50938
What is the shape of the universe? (Intermediate) Jan 99 111495
How can geometry be different in space? (Intermediate) Jan 99 60198
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across? (Advanced) Jan 99 84726
Why are there blue shifted galaxies? (Intermediate) Jan 99 85321
What is a dimension? (Intermediate) Jan 99 81941
Will we get sucked into the black hole at the center of the Milky Way? (Beginner) Jan 99 119365
Can you tell time by the Big Dipper? (Beginner) Jan 99 57750
How powerful are quasars? (Intermediate) Jan 99 54345
What happens when you change the mass of a White Dwarf or Neutron Star? (Intermediate) Jan 99 76181
What caused Shoemaker-Levy 9 to split up? (Advanced) Jan 99 60911
How do we know if the universe will keep expanding forever? (Intermediate) Jan 99 120051
Why do planets not twinkle? (Intermediate) Jan 99 156080
Can we find the place where the Big Bang happened? (Intermediate) Jan 99 223704
What are the boundaries of the constellations? (Beginner) Jan 99 58544
Why is our solar system so different from all the others we've found? (Intermediate) Jan 99 87307
How do distant galaxies differ from those nearby? (Advanced) Jan 99 58395
How long does it take for the Sun's light to reach us? (Beginner) Jan 99 708724
Do electrons age? (Beginner) Jan 99 52626
What causes seasons? (Beginner) Jan 99 120631
What is time dilation? (Intermediate) Dec 98 104014

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