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 63464
Do you believe in UFOs? (Beginner) Apr 99 49505
Why are there no craters on Earth? Did all the meteorites miss us? (Beginner) Apr 99 64816
Can life exist on the recently discovered extrasolar planets? (Beginner) Apr 99 53425
How can two moons of Saturn share the same orbit? (Intermediate) Apr 99 71020
How do you measure the mass of a star? (Beginner) Apr 99 114926
What direction do planets rotate? (Beginner) Apr 99 264632
Can you hear sounds in space? (Beginner) Apr 99 494983
How can we measure distances to more stars? (Intermediate) Apr 99 49839
Where did all the water in the universe come from? (Intermediate) Apr 99 91164
Why doesn't gravity change the speed of light? (Beginner) Apr 99 49440
How can you tell the difference between single and multiple extrasolar planets? (Intermediate) Apr 99 33972
Do you think it's possible to maintain life on other planets? (Beginner) Apr 99 60305
When unmanned spacecraft accelerate in space, what causes them to slow down? (Intermediate) Apr 99 49103
What are Altitude and Azimuth? (Intermediate) Apr 99 107437
Do dead stars still shine? (Beginner) Apr 99 75918
How does light pollution affect astronomers? (Intermediate) Apr 99 112751
Have gravitational waves been proven to exist? (Intermediate) Apr 99 47522
What is a Dyson Sphere? (Intermediate) Apr 99 42884
Why do we not have eclipses every month? (Beginner) Mar 99 218701
Do astronomers believe in astrology? (Beginner) Mar 99 59321
Which planets have rings? (Beginner) Mar 99 447527
What equipment do I need for astrophotography? (Advanced) Mar 99 50340
How are photons created and destroyed? (Advanced) Mar 99 94989
Why search for only Earth-like life on other planets? (Beginner) Mar 99 42787
How do we know the mass of the Earth and the Moon? (Advanced) Mar 99 134639
Why is twilight short near the equator? (Intermediate) Mar 99 126918
What kind of telescope should I use for astrophotography? (Beginner) Mar 99 43955
Does the shuttle worry about space junk? (Beginner) Mar 99 38919
Why do stars change colour when they twinkle? (Beginner) Mar 99 137741
How can I contribute to science as an amateur astronomer? (Advanced) Mar 99 47427
Can the theory of formation of the solar system explain all the observables? (Intermediate) Mar 99 55449
What do stellar classifications mean? (Beginner) Mar 99 41604
Could we be seeing dead stars? (Beginner) Mar 99 47667
Can one star orbit another? (Beginner) Mar 99 49569
Why can't you see stars during the day? (Beginner) Mar 99 146047
What would happen if you took off your helmet in space? (Beginner) Mar 99 152121
What makes a satellite geosyncronise itself with Earth's orbit? (Intermediate) Mar 99 53894
Why is it important to study meteorites? (Beginner) Mar 99 63217
Why does the Moon look big on the horizon? (Intermediate) Mar 99 77497
When was the last time all of the planets were aligned? (Beginner) Mar 99 518009
How did asteroids form and what is the difference between an asteroid and a comet? (Beginner) Mar 99 101626
How do we measure distances to other stars? (Beginner) Mar 99 53040
What are the requirements for being a planet? (Beginner) Mar 99 194436
If comets are boiling away, why are there any left? (Intermediate) Mar 99 62983
What is sidereal time? (Beginner) Mar 99 51123
Which hemisphere has the best view of the Milky Way? (Beginner) Mar 99 90933
Why do all the planets orbit in the same plane? (Intermediate) Mar 99 278737
How are elements heavier than iron formed? (Intermediate) Feb 99 167286
Are time machines possible? (Intermediate) Jan 99 50574
Are the asteroids the remains of a planet which broke apart? (Beginner) Jan 99 50402
What is a nova? (Beginner) Jan 99 193672
Who first measured the speed of light? (Intermediate) Jan 99 143940
How do gravitons escape black holes to tell the universe about their gravity? (Advanced) Jan 99 89967
How do we know the age of the Universe and the Earth? (Intermediate) Jan 99 274432
What is that ring (or rainbow) around the moon? (Beginner) Jan 99 348000
How could galaxies have gotten so far away in only 14 billion years? (Intermediate) Jan 99 52028
Where are stars born? (Beginner) Jan 99 83435
Can you see satellites? (Beginner) Jan 99 76854
What kinds of star clusters are there? (Intermediate) Jan 99 41377
What is the life cycle of a star? (Intermediate) Jan 99 294266
How do I tell which planet is which? (Beginner) Jan 99 67382
Why do stars twinkle? (Beginner) Jan 99 420272
Can HST see the Oort cloud? (Intermediate) Jan 99 38222
What is the shape of the universe? (Intermediate) Jan 99 91159
How can geometry be different in space? (Intermediate) Jan 99 47621
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across? (Advanced) Jan 99 66804
Why are there blue shifted galaxies? (Intermediate) Jan 99 66832
What is a dimension? (Intermediate) Jan 99 63429
Will we get sucked into the black hole at the center of the Milky Way? (Beginner) Jan 99 89583
Can you tell time by the Big Dipper? (Beginner) Jan 99 44515
How powerful are quasars? (Intermediate) Jan 99 42855
What happens when you change the mass of a White Dwarf or Neutron Star? (Intermediate) Jan 99 57784
What caused Shoemaker-Levy 9 to split up? (Advanced) Jan 99 45679
How do we know if the universe will keep expanding forever? (Intermediate) Jan 99 82872
Why do planets not twinkle? (Intermediate) Jan 99 118609
Can we find the place where the Big Bang happened? (Intermediate) Jan 99 142645
What are the boundaries of the constellations? (Beginner) Jan 99 43446
Why is our solar system so different from all the others we've found? (Intermediate) Jan 99 66138
How do distant galaxies differ from those nearby? (Advanced) Jan 99 42039
How long does it take for the Sun's light to reach us? (Beginner) Jan 99 591516
Do electrons age? (Beginner) Jan 99 40329
What causes seasons? (Beginner) Jan 99 94968
What is time dilation? (Intermediate) Dec 98 78611

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