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 77879
Do you believe in UFOs? (Beginner) Apr 99 57823
Why are there no craters on Earth? Did all the meteorites miss us? (Beginner) Apr 99 90247
Can life exist on the recently discovered extrasolar planets? (Beginner) Apr 99 63168
How can two moons of Saturn share the same orbit? (Intermediate) Apr 99 82645
How do you measure the mass of a star? (Beginner) Apr 99 142630
What direction do planets rotate? (Beginner) Apr 99 347065
Can you hear sounds in space? (Beginner) Apr 99 564173
How can we measure distances to more stars? (Intermediate) Apr 99 59727
Where did all the water in the universe come from? (Intermediate) Apr 99 110595
Why doesn't gravity change the speed of light? (Beginner) Apr 99 56760
How can you tell the difference between single and multiple extrasolar planets? (Intermediate) Apr 99 41231
Do you think it's possible to maintain life on other planets? (Beginner) Apr 99 68540
When unmanned spacecraft accelerate in space, what causes them to slow down? (Intermediate) Apr 99 61119
What are Altitude and Azimuth? (Intermediate) Apr 99 133780
Do dead stars still shine? (Beginner) Apr 99 89758
How does light pollution affect astronomers? (Intermediate) Apr 99 134353
Have gravitational waves been proven to exist? (Intermediate) Apr 99 57926
What is a Dyson Sphere? (Intermediate) Apr 99 50380
Why do we not have eclipses every month? (Beginner) Mar 99 289665
Do astronomers believe in astrology? (Beginner) Mar 99 72034
Which planets have rings? (Beginner) Mar 99 546020
What equipment do I need for astrophotography? (Advanced) Mar 99 60855
How are photons created and destroyed? (Advanced) Mar 99 126605
Why search for only Earth-like life on other planets? (Beginner) Mar 99 51350
How do we know the mass of the Earth and the Moon? (Advanced) Mar 99 161011
Why is twilight short near the equator? (Intermediate) Mar 99 163684
What kind of telescope should I use for astrophotography? (Beginner) Mar 99 52349
Does the shuttle worry about space junk? (Beginner) Mar 99 47040
Why do stars change colour when they twinkle? (Beginner) Mar 99 169720
How can I contribute to science as an amateur astronomer? (Advanced) Mar 99 58166
Can the theory of formation of the solar system explain all the observables? (Intermediate) Mar 99 68821
What do stellar classifications mean? (Beginner) Mar 99 52045
Could we be seeing dead stars? (Beginner) Mar 99 57826
Can one star orbit another? (Beginner) Mar 99 58576
Why can't you see stars during the day? (Beginner) Mar 99 192531
What would happen if you took off your helmet in space? (Beginner) Mar 99 229042
What makes a satellite geosyncronise itself with Earth's orbit? (Intermediate) Mar 99 68191
Why is it important to study meteorites? (Beginner) Mar 99 83578
Why does the Moon look big on the horizon? (Intermediate) Mar 99 86511
When was the last time all of the planets were aligned? (Beginner) Mar 99 674200
How did asteroids form and what is the difference between an asteroid and a comet? (Beginner) Mar 99 116349
How do we measure distances to other stars? (Beginner) Mar 99 62679
What are the requirements for being a planet? (Beginner) Mar 99 262860
If comets are boiling away, why are there any left? (Intermediate) Mar 99 71898
What is sidereal time? (Beginner) Mar 99 69147
Which hemisphere has the best view of the Milky Way? (Beginner) Mar 99 107150
Why do all the planets orbit in the same plane? (Intermediate) Mar 99 350504
How are elements heavier than iron formed? (Intermediate) Feb 99 207043
Are time machines possible? (Intermediate) Jan 99 57960
Are the asteroids the remains of a planet which broke apart? (Beginner) Jan 99 62740
What is a nova? (Beginner) Jan 99 218378
Who first measured the speed of light? (Intermediate) Jan 99 159669
How do gravitons escape black holes to tell the universe about their gravity? (Advanced) Jan 99 110069
How do we know the age of the Universe and the Earth? (Intermediate) Jan 99 301969
What is that ring (or rainbow) around the moon? (Beginner) Jan 99 389908
How could galaxies have gotten so far away in only 14 billion years? (Intermediate) Jan 99 63937
Where are stars born? (Beginner) Jan 99 94293
Can you see satellites? (Beginner) Jan 99 88045
What kinds of star clusters are there? (Intermediate) Jan 99 50633
What is the life cycle of a star? (Intermediate) Jan 99 317101
How do I tell which planet is which? (Beginner) Jan 99 88300
Why do stars twinkle? (Beginner) Jan 99 514328
Can HST see the Oort cloud? (Intermediate) Jan 99 46544
What is the shape of the universe? (Intermediate) Jan 99 104230
How can geometry be different in space? (Intermediate) Jan 99 56076
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across? (Advanced) Jan 99 77534
Why are there blue shifted galaxies? (Intermediate) Jan 99 78624
What is a dimension? (Intermediate) Jan 99 75827
Will we get sucked into the black hole at the center of the Milky Way? (Beginner) Jan 99 110915
Can you tell time by the Big Dipper? (Beginner) Jan 99 53215
How powerful are quasars? (Intermediate) Jan 99 50406
What happens when you change the mass of a White Dwarf or Neutron Star? (Intermediate) Jan 99 70226
What caused Shoemaker-Levy 9 to split up? (Advanced) Jan 99 55811
How do we know if the universe will keep expanding forever? (Intermediate) Jan 99 109519
Why do planets not twinkle? (Intermediate) Jan 99 143859
Can we find the place where the Big Bang happened? (Intermediate) Jan 99 182511
What are the boundaries of the constellations? (Beginner) Jan 99 52897
Why is our solar system so different from all the others we've found? (Intermediate) Jan 99 80409
How do distant galaxies differ from those nearby? (Advanced) Jan 99 52703
How long does it take for the Sun's light to reach us? (Beginner) Jan 99 671049
Do electrons age? (Beginner) Jan 99 48270
What causes seasons? (Beginner) Jan 99 110460
What is time dilation? (Intermediate) Dec 98 95245

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