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 65950
Do you believe in UFOs? (Beginner) Apr 99 50796
Why are there no craters on Earth? Did all the meteorites miss us? (Beginner) Apr 99 69151
Can life exist on the recently discovered extrasolar planets? (Beginner) Apr 99 55052
How can two moons of Saturn share the same orbit? (Intermediate) Apr 99 72906
How do you measure the mass of a star? (Beginner) Apr 99 119792
What direction do planets rotate? (Beginner) Apr 99 277828
Can you hear sounds in space? (Beginner) Apr 99 509135
How can we measure distances to more stars? (Intermediate) Apr 99 51416
Where did all the water in the universe come from? (Intermediate) Apr 99 94022
Why doesn't gravity change the speed of light? (Beginner) Apr 99 50564
How can you tell the difference between single and multiple extrasolar planets? (Intermediate) Apr 99 35163
Do you think it's possible to maintain life on other planets? (Beginner) Apr 99 61459
When unmanned spacecraft accelerate in space, what causes them to slow down? (Intermediate) Apr 99 50870
What are Altitude and Azimuth? (Intermediate) Apr 99 112066
Do dead stars still shine? (Beginner) Apr 99 78126
How does light pollution affect astronomers? (Intermediate) Apr 99 116383
Have gravitational waves been proven to exist? (Intermediate) Apr 99 49055
What is a Dyson Sphere? (Intermediate) Apr 99 44108
Why do we not have eclipses every month? (Beginner) Mar 99 233621
Do astronomers believe in astrology? (Beginner) Mar 99 61334
Which planets have rings? (Beginner) Mar 99 464354
What equipment do I need for astrophotography? (Advanced) Mar 99 52100
How are photons created and destroyed? (Advanced) Mar 99 99978
Why search for only Earth-like life on other planets? (Beginner) Mar 99 44158
How do we know the mass of the Earth and the Moon? (Advanced) Mar 99 139307
Why is twilight short near the equator? (Intermediate) Mar 99 131779
What kind of telescope should I use for astrophotography? (Beginner) Mar 99 45324
Does the shuttle worry about space junk? (Beginner) Mar 99 40134
Why do stars change colour when they twinkle? (Beginner) Mar 99 142890
How can I contribute to science as an amateur astronomer? (Advanced) Mar 99 48971
Can the theory of formation of the solar system explain all the observables? (Intermediate) Mar 99 57557
What do stellar classifications mean? (Beginner) Mar 99 43349
Could we be seeing dead stars? (Beginner) Mar 99 49327
Can one star orbit another? (Beginner) Mar 99 51267
Why can't you see stars during the day? (Beginner) Mar 99 153708
What would happen if you took off your helmet in space? (Beginner) Mar 99 163701
What makes a satellite geosyncronise itself with Earth's orbit? (Intermediate) Mar 99 56083
Why is it important to study meteorites? (Beginner) Mar 99 66823
Why does the Moon look big on the horizon? (Intermediate) Mar 99 78953
When was the last time all of the planets were aligned? (Beginner) Mar 99 545660
How did asteroids form and what is the difference between an asteroid and a comet? (Beginner) Mar 99 103989
How do we measure distances to other stars? (Beginner) Mar 99 54604
What are the requirements for being a planet? (Beginner) Mar 99 205388
If comets are boiling away, why are there any left? (Intermediate) Mar 99 64346
What is sidereal time? (Beginner) Mar 99 53649
Which hemisphere has the best view of the Milky Way? (Beginner) Mar 99 93456
Why do all the planets orbit in the same plane? (Intermediate) Mar 99 293068
How are elements heavier than iron formed? (Intermediate) Feb 99 173762
Are time machines possible? (Intermediate) Jan 99 51804
Are the asteroids the remains of a planet which broke apart? (Beginner) Jan 99 52537
What is a nova? (Beginner) Jan 99 198068
Who first measured the speed of light? (Intermediate) Jan 99 146692
How do gravitons escape black holes to tell the universe about their gravity? (Advanced) Jan 99 92814
How do we know the age of the Universe and the Earth? (Intermediate) Jan 99 279624
What is that ring (or rainbow) around the moon? (Beginner) Jan 99 355402
How could galaxies have gotten so far away in only 14 billion years? (Intermediate) Jan 99 53963
Where are stars born? (Beginner) Jan 99 85187
Can you see satellites? (Beginner) Jan 99 78530
What kinds of star clusters are there? (Intermediate) Jan 99 43024
What is the life cycle of a star? (Intermediate) Jan 99 298309
How do I tell which planet is which? (Beginner) Jan 99 70016
Why do stars twinkle? (Beginner) Jan 99 433099
Can HST see the Oort cloud? (Intermediate) Jan 99 39593
What is the shape of the universe? (Intermediate) Jan 99 93363
How can geometry be different in space? (Intermediate) Jan 99 49029
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across? (Advanced) Jan 99 68517
Why are there blue shifted galaxies? (Intermediate) Jan 99 68702
What is a dimension? (Intermediate) Jan 99 65281
Will we get sucked into the black hole at the center of the Milky Way? (Beginner) Jan 99 93551
Can you tell time by the Big Dipper? (Beginner) Jan 99 45837
How powerful are quasars? (Intermediate) Jan 99 44079
What happens when you change the mass of a White Dwarf or Neutron Star? (Intermediate) Jan 99 59921
What caused Shoemaker-Levy 9 to split up? (Advanced) Jan 99 47330
How do we know if the universe will keep expanding forever? (Intermediate) Jan 99 87109
Why do planets not twinkle? (Intermediate) Jan 99 122635
Can we find the place where the Big Bang happened? (Intermediate) Jan 99 147292
What are the boundaries of the constellations? (Beginner) Jan 99 44956
Why is our solar system so different from all the others we've found? (Intermediate) Jan 99 68170
How do distant galaxies differ from those nearby? (Advanced) Jan 99 43770
How long does it take for the Sun's light to reach us? (Beginner) Jan 99 605881
Do electrons age? (Beginner) Jan 99 41660
What causes seasons? (Beginner) Jan 99 97242
What is time dilation? (Intermediate) Dec 98 81510

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