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 74435
Do you believe in UFOs? (Beginner) Apr 99 55487
Why are there no craters on Earth? Did all the meteorites miss us? (Beginner) Apr 99 84653
Can life exist on the recently discovered extrasolar planets? (Beginner) Apr 99 60801
How can two moons of Saturn share the same orbit? (Intermediate) Apr 99 79771
How do you measure the mass of a star? (Beginner) Apr 99 136937
What direction do planets rotate? (Beginner) Apr 99 330904
Can you hear sounds in space? (Beginner) Apr 99 551519
How can we measure distances to more stars? (Intermediate) Apr 99 57244
Where did all the water in the universe come from? (Intermediate) Apr 99 105467
Why doesn't gravity change the speed of light? (Beginner) Apr 99 54767
How can you tell the difference between single and multiple extrasolar planets? (Intermediate) Apr 99 39344
Do you think it's possible to maintain life on other planets? (Beginner) Apr 99 66289
When unmanned spacecraft accelerate in space, what causes them to slow down? (Intermediate) Apr 99 57863
What are Altitude and Azimuth? (Intermediate) Apr 99 128795
Do dead stars still shine? (Beginner) Apr 99 86166
How does light pollution affect astronomers? (Intermediate) Apr 99 129561
Have gravitational waves been proven to exist? (Intermediate) Apr 99 55059
What is a Dyson Sphere? (Intermediate) Apr 99 48546
Why do we not have eclipses every month? (Beginner) Mar 99 276598
Do astronomers believe in astrology? (Beginner) Mar 99 68629
Which planets have rings? (Beginner) Mar 99 525544
What equipment do I need for astrophotography? (Advanced) Mar 99 58395
How are photons created and destroyed? (Advanced) Mar 99 119263
Why search for only Earth-like life on other planets? (Beginner) Mar 99 49126
How do we know the mass of the Earth and the Moon? (Advanced) Mar 99 155199
Why is twilight short near the equator? (Intermediate) Mar 99 153708
What kind of telescope should I use for astrophotography? (Beginner) Mar 99 50199
Does the shuttle worry about space junk? (Beginner) Mar 99 44905
Why do stars change colour when they twinkle? (Beginner) Mar 99 162971
How can I contribute to science as an amateur astronomer? (Advanced) Mar 99 55449
Can the theory of formation of the solar system explain all the observables? (Intermediate) Mar 99 65533
What do stellar classifications mean? (Beginner) Mar 99 49471
Could we be seeing dead stars? (Beginner) Mar 99 55144
Can one star orbit another? (Beginner) Mar 99 56550
Why can't you see stars during the day? (Beginner) Mar 99 183380
What would happen if you took off your helmet in space? (Beginner) Mar 99 215325
What makes a satellite geosyncronise itself with Earth's orbit? (Intermediate) Mar 99 64301
Why is it important to study meteorites? (Beginner) Mar 99 79433
Why does the Moon look big on the horizon? (Intermediate) Mar 99 84159
When was the last time all of the planets were aligned? (Beginner) Mar 99 642032
How did asteroids form and what is the difference between an asteroid and a comet? (Beginner) Mar 99 112900
How do we measure distances to other stars? (Beginner) Mar 99 60343
What are the requirements for being a planet? (Beginner) Mar 99 243017
If comets are boiling away, why are there any left? (Intermediate) Mar 99 69645
What is sidereal time? (Beginner) Mar 99 64986
Which hemisphere has the best view of the Milky Way? (Beginner) Mar 99 102984
Why do all the planets orbit in the same plane? (Intermediate) Mar 99 334419
How are elements heavier than iron formed? (Intermediate) Feb 99 198557
Are time machines possible? (Intermediate) Jan 99 56128
Are the asteroids the remains of a planet which broke apart? (Beginner) Jan 99 59987
What is a nova? (Beginner) Jan 99 212443
Who first measured the speed of light? (Intermediate) Jan 99 156280
How do gravitons escape black holes to tell the universe about their gravity? (Advanced) Jan 99 105044
How do we know the age of the Universe and the Earth? (Intermediate) Jan 99 295725
What is that ring (or rainbow) around the moon? (Beginner) Jan 99 380835
How could galaxies have gotten so far away in only 14 billion years? (Intermediate) Jan 99 60819
Where are stars born? (Beginner) Jan 99 91480
Can you see satellites? (Beginner) Jan 99 85319
What kinds of star clusters are there? (Intermediate) Jan 99 48389
What is the life cycle of a star? (Intermediate) Jan 99 312151
How do I tell which planet is which? (Beginner) Jan 99 83007
Why do stars twinkle? (Beginner) Jan 99 495858
Can HST see the Oort cloud? (Intermediate) Jan 99 44333
What is the shape of the universe? (Intermediate) Jan 99 101222
How can geometry be different in space? (Intermediate) Jan 99 54041
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across? (Advanced) Jan 99 74626
Why are there blue shifted galaxies? (Intermediate) Jan 99 75716
What is a dimension? (Intermediate) Jan 99 72804
Will we get sucked into the black hole at the center of the Milky Way? (Beginner) Jan 99 106391
Can you tell time by the Big Dipper? (Beginner) Jan 99 50871
How powerful are quasars? (Intermediate) Jan 99 48429
What happens when you change the mass of a White Dwarf or Neutron Star? (Intermediate) Jan 99 67213
What caused Shoemaker-Levy 9 to split up? (Advanced) Jan 99 53482
How do we know if the universe will keep expanding forever? (Intermediate) Jan 99 103165
Why do planets not twinkle? (Intermediate) Jan 99 138510
Can we find the place where the Big Bang happened? (Intermediate) Jan 99 168973
What are the boundaries of the constellations? (Beginner) Jan 99 50517
Why is our solar system so different from all the others we've found? (Intermediate) Jan 99 76738
How do distant galaxies differ from those nearby? (Advanced) Jan 99 50002
How long does it take for the Sun's light to reach us? (Beginner) Jan 99 656048
Do electrons age? (Beginner) Jan 99 46110
What causes seasons? (Beginner) Jan 99 106720
What is time dilation? (Intermediate) Dec 98 90999

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