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 71994
Do you believe in UFOs? (Beginner) Apr 99 53843
Why are there no craters on Earth? Did all the meteorites miss us? (Beginner) Apr 99 79408
Can life exist on the recently discovered extrasolar planets? (Beginner) Apr 99 58981
How can two moons of Saturn share the same orbit? (Intermediate) Apr 99 77650
How do you measure the mass of a star? (Beginner) Apr 99 131427
What direction do planets rotate? (Beginner) Apr 99 312666
Can you hear sounds in space? (Beginner) Apr 99 538028
How can we measure distances to more stars? (Intermediate) Apr 99 55274
Where did all the water in the universe come from? (Intermediate) Apr 99 101791
Why doesn't gravity change the speed of light? (Beginner) Apr 99 53488
How can you tell the difference between single and multiple extrasolar planets? (Intermediate) Apr 99 38127
Do you think it's possible to maintain life on other planets? (Beginner) Apr 99 64692
When unmanned spacecraft accelerate in space, what causes them to slow down? (Intermediate) Apr 99 55452
What are Altitude and Azimuth? (Intermediate) Apr 99 123336
Do dead stars still shine? (Beginner) Apr 99 83269
How does light pollution affect astronomers? (Intermediate) Apr 99 125413
Have gravitational waves been proven to exist? (Intermediate) Apr 99 53104
What is a Dyson Sphere? (Intermediate) Apr 99 47152
Why do we not have eclipses every month? (Beginner) Mar 99 260061
Do astronomers believe in astrology? (Beginner) Mar 99 66162
Which planets have rings? (Beginner) Mar 99 507361
What equipment do I need for astrophotography? (Advanced) Mar 99 56501
How are photons created and destroyed? (Advanced) Mar 99 113529
Why search for only Earth-like life on other planets? (Beginner) Mar 99 47482
How do we know the mass of the Earth and the Moon? (Advanced) Mar 99 150162
Why is twilight short near the equator? (Intermediate) Mar 99 147301
What kind of telescope should I use for astrophotography? (Beginner) Mar 99 48663
Does the shuttle worry about space junk? (Beginner) Mar 99 43261
Why do stars change colour when they twinkle? (Beginner) Mar 99 156885
How can I contribute to science as an amateur astronomer? (Advanced) Mar 99 53486
Can the theory of formation of the solar system explain all the observables? (Intermediate) Mar 99 63235
What do stellar classifications mean? (Beginner) Mar 99 47418
Could we be seeing dead stars? (Beginner) Mar 99 53114
Can one star orbit another? (Beginner) Mar 99 55101
Why can't you see stars during the day? (Beginner) Mar 99 173832
What would happen if you took off your helmet in space? (Beginner) Mar 99 194388
What makes a satellite geosyncronise itself with Earth's orbit? (Intermediate) Mar 99 61441
Why is it important to study meteorites? (Beginner) Mar 99 75765
Why does the Moon look big on the horizon? (Intermediate) Mar 99 82473
When was the last time all of the planets were aligned? (Beginner) Mar 99 616530
How did asteroids form and what is the difference between an asteroid and a comet? (Beginner) Mar 99 110232
How do we measure distances to other stars? (Beginner) Mar 99 58480
What are the requirements for being a planet? (Beginner) Mar 99 228448
If comets are boiling away, why are there any left? (Intermediate) Mar 99 67950
What is sidereal time? (Beginner) Mar 99 61571
Which hemisphere has the best view of the Milky Way? (Beginner) Mar 99 100274
Why do all the planets orbit in the same plane? (Intermediate) Mar 99 320084
How are elements heavier than iron formed? (Intermediate) Feb 99 193975
Are time machines possible? (Intermediate) Jan 99 54734
Are the asteroids the remains of a planet which broke apart? (Beginner) Jan 99 57953
What is a nova? (Beginner) Jan 99 207781
Who first measured the speed of light? (Intermediate) Jan 99 152728
How do gravitons escape black holes to tell the universe about their gravity? (Advanced) Jan 99 100739
How do we know the age of the Universe and the Earth? (Intermediate) Jan 99 291211
What is that ring (or rainbow) around the moon? (Beginner) Jan 99 370492
How could galaxies have gotten so far away in only 14 billion years? (Intermediate) Jan 99 58521
Where are stars born? (Beginner) Jan 99 89372
Can you see satellites? (Beginner) Jan 99 83419
What kinds of star clusters are there? (Intermediate) Jan 99 46739
What is the life cycle of a star? (Intermediate) Jan 99 308017
How do I tell which planet is which? (Beginner) Jan 99 79365
Why do stars twinkle? (Beginner) Jan 99 467912
Can HST see the Oort cloud? (Intermediate) Jan 99 42923
What is the shape of the universe? (Intermediate) Jan 99 98666
How can geometry be different in space? (Intermediate) Jan 99 52623
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across? (Advanced) Jan 99 72542
Why are there blue shifted galaxies? (Intermediate) Jan 99 73561
What is a dimension? (Intermediate) Jan 99 70609
Will we get sucked into the black hole at the center of the Milky Way? (Beginner) Jan 99 101601
Can you tell time by the Big Dipper? (Beginner) Jan 99 49051
How powerful are quasars? (Intermediate) Jan 99 47088
What happens when you change the mass of a White Dwarf or Neutron Star? (Intermediate) Jan 99 65032
What caused Shoemaker-Levy 9 to split up? (Advanced) Jan 99 51526
How do we know if the universe will keep expanding forever? (Intermediate) Jan 99 99690
Why do planets not twinkle? (Intermediate) Jan 99 133273
Can we find the place where the Big Bang happened? (Intermediate) Jan 99 159543
What are the boundaries of the constellations? (Beginner) Jan 99 48516
Why is our solar system so different from all the others we've found? (Intermediate) Jan 99 74481
How do distant galaxies differ from those nearby? (Advanced) Jan 99 48097
How long does it take for the Sun's light to reach us? (Beginner) Jan 99 640572
Do electrons age? (Beginner) Jan 99 44721
What causes seasons? (Beginner) Jan 99 103306
What is time dilation? (Intermediate) Dec 98 87956

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