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 55270
Do you believe in UFOs? (Beginner) Apr 99 44478
Why are there no craters on Earth? Did all the meteorites miss us? (Beginner) Apr 99 54383
Can life exist on the recently discovered extrasolar planets? (Beginner) Apr 99 47366
How can two moons of Saturn share the same orbit? (Intermediate) Apr 99 64898
How do you measure the mass of a star? (Beginner) Apr 99 101732
What direction do planets rotate? (Beginner) Apr 99 232327
Can you hear sounds in space? (Beginner) Apr 99 458865
How can we measure distances to more stars? (Intermediate) Apr 99 44189
Where did all the water in the universe come from? (Intermediate) Apr 99 82339
Why doesn't gravity change the speed of light? (Beginner) Apr 99 45017
How can you tell the difference between single and multiple extrasolar planets? (Intermediate) Apr 99 29668
Do you think it's possible to maintain life on other planets? (Beginner) Apr 99 55448
When unmanned spacecraft accelerate in space, what causes them to slow down? (Intermediate) Apr 99 43447
What are Altitude and Azimuth? (Intermediate) Apr 99 94421
Do dead stars still shine? (Beginner) Apr 99 68751
How does light pollution affect astronomers? (Intermediate) Apr 99 102823
Have gravitational waves been proven to exist? (Intermediate) Apr 99 41638
What is a Dyson Sphere? (Intermediate) Apr 99 38425
Why do we not have eclipses every month? (Beginner) Mar 99 157865
Do astronomers believe in astrology? (Beginner) Mar 99 52358
Which planets have rings? (Beginner) Mar 99 404230
What equipment do I need for astrophotography? (Advanced) Mar 99 44273
How are photons created and destroyed? (Advanced) Mar 99 79542
Why search for only Earth-like life on other planets? (Beginner) Mar 99 37709
How do we know the mass of the Earth and the Moon? (Advanced) Mar 99 117668
Why is twilight short near the equator? (Intermediate) Mar 99 109402
What kind of telescope should I use for astrophotography? (Beginner) Mar 99 38908
Does the shuttle worry about space junk? (Beginner) Mar 99 34306
Why do stars change colour when they twinkle? (Beginner) Mar 99 121637
How can I contribute to science as an amateur astronomer? (Advanced) Mar 99 42092
Can the theory of formation of the solar system explain all the observables? (Intermediate) Mar 99 46261
What do stellar classifications mean? (Beginner) Mar 99 36036
Could we be seeing dead stars? (Beginner) Mar 99 41394
Can one star orbit another? (Beginner) Mar 99 44058
Why can't you see stars during the day? (Beginner) Mar 99 126899
What would happen if you took off your helmet in space? (Beginner) Mar 99 127357
What makes a satellite geosyncronise itself with Earth's orbit? (Intermediate) Mar 99 45947
Why is it important to study meteorites? (Beginner) Mar 99 53014
Why does the Moon look big on the horizon? (Intermediate) Mar 99 71938
When was the last time all of the planets were aligned? (Beginner) Mar 99 414563
How did asteroids form and what is the difference between an asteroid and a comet? (Beginner) Mar 99 93246
How do we measure distances to other stars? (Beginner) Mar 99 47225
What are the requirements for being a planet? (Beginner) Mar 99 166858
If comets are boiling away, why are there any left? (Intermediate) Mar 99 58423
What is sidereal time? (Beginner) Mar 99 44117
Which hemisphere has the best view of the Milky Way? (Beginner) Mar 99 81752
Why do all the planets orbit in the same plane? (Intermediate) Mar 99 237542
How are elements heavier than iron formed? (Intermediate) Feb 99 132776
Are time machines possible? (Intermediate) Jan 99 46106
Are the asteroids the remains of a planet which broke apart? (Beginner) Jan 99 43864
What is a nova? (Beginner) Jan 99 182013
Who first measured the speed of light? (Intermediate) Jan 99 135956
How do gravitons escape black holes to tell the universe about their gravity? (Advanced) Jan 99 79871
How do we know the age of the Universe and the Earth? (Intermediate) Jan 99 258123
What is that ring (or rainbow) around the moon? (Beginner) Jan 99 323677
How could galaxies have gotten so far away in only 14 billion years? (Intermediate) Jan 99 45701
Where are stars born? (Beginner) Jan 99 77290
Can you see satellites? (Beginner) Jan 99 71727
What kinds of star clusters are there? (Intermediate) Jan 99 36296
What is the life cycle of a star? (Intermediate) Jan 99 282013
How do I tell which planet is which? (Beginner) Jan 99 59624
Why do stars twinkle? (Beginner) Jan 99 383702
Can HST see the Oort cloud? (Intermediate) Jan 99 33653
What is the shape of the universe? (Intermediate) Jan 99 83029
How can geometry be different in space? (Intermediate) Jan 99 42732
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across? (Advanced) Jan 99 61303
Why are there blue shifted galaxies? (Intermediate) Jan 99 60001
What is a dimension? (Intermediate) Jan 99 57324
Will we get sucked into the black hole at the center of the Milky Way? (Beginner) Jan 99 78460
Can you tell time by the Big Dipper? (Beginner) Jan 99 39509
How powerful are quasars? (Intermediate) Jan 99 38265
What happens when you change the mass of a White Dwarf or Neutron Star? (Intermediate) Jan 99 51501
What caused Shoemaker-Levy 9 to split up? (Advanced) Jan 99 40663
How do we know if the universe will keep expanding forever? (Intermediate) Jan 99 68765
Why do planets not twinkle? (Intermediate) Jan 99 105824
Can we find the place where the Big Bang happened? (Intermediate) Jan 99 122743
What are the boundaries of the constellations? (Beginner) Jan 99 38009
Why is our solar system so different from all the others we've found? (Intermediate) Jan 99 58414
How do distant galaxies differ from those nearby? (Advanced) Jan 99 36389
How long does it take for the Sun's light to reach us? (Beginner) Jan 99 544508
Do electrons age? (Beginner) Jan 99 35372
What causes seasons? (Beginner) Jan 99 87020
What is time dilation? (Intermediate) Dec 98 68737

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