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 70557
Do you believe in UFOs? (Beginner) Apr 99 53133
Why are there no craters on Earth? Did all the meteorites miss us? (Beginner) Apr 99 75798
Can life exist on the recently discovered extrasolar planets? (Beginner) Apr 99 58109
How can two moons of Saturn share the same orbit? (Intermediate) Apr 99 76577
How do you measure the mass of a star? (Beginner) Apr 99 127693
What direction do planets rotate? (Beginner) Apr 99 302173
Can you hear sounds in space? (Beginner) Apr 99 530983
How can we measure distances to more stars? (Intermediate) Apr 99 54391
Where did all the water in the universe come from? (Intermediate) Apr 99 99935
Why doesn't gravity change the speed of light? (Beginner) Apr 99 52855
How can you tell the difference between single and multiple extrasolar planets? (Intermediate) Apr 99 37447
Do you think it's possible to maintain life on other planets? (Beginner) Apr 99 63995
When unmanned spacecraft accelerate in space, what causes them to slow down? (Intermediate) Apr 99 54394
What are Altitude and Azimuth? (Intermediate) Apr 99 120284
Do dead stars still shine? (Beginner) Apr 99 82058
How does light pollution affect astronomers? (Intermediate) Apr 99 122819
Have gravitational waves been proven to exist? (Intermediate) Apr 99 52196
What is a Dyson Sphere? (Intermediate) Apr 99 46431
Why do we not have eclipses every month? (Beginner) Mar 99 251297
Do astronomers believe in astrology? (Beginner) Mar 99 65111
Which planets have rings? (Beginner) Mar 99 494975
What equipment do I need for astrophotography? (Advanced) Mar 99 55596
How are photons created and destroyed? (Advanced) Mar 99 110111
Why search for only Earth-like life on other planets? (Beginner) Mar 99 46761
How do we know the mass of the Earth and the Moon? (Advanced) Mar 99 146914
Why is twilight short near the equator? (Intermediate) Mar 99 143983
What kind of telescope should I use for astrophotography? (Beginner) Mar 99 47979
Does the shuttle worry about space junk? (Beginner) Mar 99 42610
Why do stars change colour when they twinkle? (Beginner) Mar 99 153135
How can I contribute to science as an amateur astronomer? (Advanced) Mar 99 52449
Can the theory of formation of the solar system explain all the observables? (Intermediate) Mar 99 62046
What do stellar classifications mean? (Beginner) Mar 99 46537
Could we be seeing dead stars? (Beginner) Mar 99 52317
Can one star orbit another? (Beginner) Mar 99 54255
Why can't you see stars during the day? (Beginner) Mar 99 168821
What would happen if you took off your helmet in space? (Beginner) Mar 99 186340
What makes a satellite geosyncronise itself with Earth's orbit? (Intermediate) Mar 99 60133
Why is it important to study meteorites? (Beginner) Mar 99 72785
Why does the Moon look big on the horizon? (Intermediate) Mar 99 81729
When was the last time all of the planets were aligned? (Beginner) Mar 99 602875
How did asteroids form and what is the difference between an asteroid and a comet? (Beginner) Mar 99 108567
How do we measure distances to other stars? (Beginner) Mar 99 57633
What are the requirements for being a planet? (Beginner) Mar 99 221326
If comets are boiling away, why are there any left? (Intermediate) Mar 99 67045
What is sidereal time? (Beginner) Mar 99 59144
Which hemisphere has the best view of the Milky Way? (Beginner) Mar 99 98905
Why do all the planets orbit in the same plane? (Intermediate) Mar 99 313329
How are elements heavier than iron formed? (Intermediate) Feb 99 186371
Are time machines possible? (Intermediate) Jan 99 54144
Are the asteroids the remains of a planet which broke apart? (Beginner) Jan 99 56693
What is a nova? (Beginner) Jan 99 205366
Who first measured the speed of light? (Intermediate) Jan 99 151047
How do gravitons escape black holes to tell the universe about their gravity? (Advanced) Jan 99 98850
How do we know the age of the Universe and the Earth? (Intermediate) Jan 99 288322
What is that ring (or rainbow) around the moon? (Beginner) Jan 99 366393
How could galaxies have gotten so far away in only 14 billion years? (Intermediate) Jan 99 57444
Where are stars born? (Beginner) Jan 99 88378
Can you see satellites? (Beginner) Jan 99 82360
What kinds of star clusters are there? (Intermediate) Jan 99 45879
What is the life cycle of a star? (Intermediate) Jan 99 305472
How do I tell which planet is which? (Beginner) Jan 99 77655
Why do stars twinkle? (Beginner) Jan 99 456552
Can HST see the Oort cloud? (Intermediate) Jan 99 42132
What is the shape of the universe? (Intermediate) Jan 99 97482
How can geometry be different in space? (Intermediate) Jan 99 51900
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across? (Advanced) Jan 99 71659
Why are there blue shifted galaxies? (Intermediate) Jan 99 72415
What is a dimension? (Intermediate) Jan 99 69420
Will we get sucked into the black hole at the center of the Milky Way? (Beginner) Jan 99 99616
Can you tell time by the Big Dipper? (Beginner) Jan 99 48324
How powerful are quasars? (Intermediate) Jan 99 46427
What happens when you change the mass of a White Dwarf or Neutron Star? (Intermediate) Jan 99 63934
What caused Shoemaker-Levy 9 to split up? (Advanced) Jan 99 50472
How do we know if the universe will keep expanding forever? (Intermediate) Jan 99 97197
Why do planets not twinkle? (Intermediate) Jan 99 130753
Can we find the place where the Big Bang happened? (Intermediate) Jan 99 156549
What are the boundaries of the constellations? (Beginner) Jan 99 47723
Why is our solar system so different from all the others we've found? (Intermediate) Jan 99 73086
How do distant galaxies differ from those nearby? (Advanced) Jan 99 47076
How long does it take for the Sun's light to reach us? (Beginner) Jan 99 631955
Do electrons age? (Beginner) Jan 99 44087
What causes seasons? (Beginner) Jan 99 101642
What is time dilation? (Intermediate) Dec 98 86398

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