Ask A Physicist: Why Believe In Dark Matter?

On today's episode of our "Ask A Physicist" series, Dr. Goldberg tackles the darker side of the universe - Dark Matter, that is. What is this curious cosmic stuff, and why should we care? » 5/01/10 9:00am 5/01/10 9:00am

How Smart Do You Need To Be To Collapse A Wave Function?

Here's the latest entry in our "ask the physicist" series. How do you find out if Schrodinger's Cat is alive or dead, for real? » 4/30/10 11:41am 4/30/10 11:41am

What Happens If You're Traveling At The Speed Of Light And Turn On Your…

One of the most popular questions from our "ask a physicist" feature was, "What happens if you're driving at the speed of light and you turn on your headlights?" The simple answer: You can't. So quit trying. » 4/29/10 12:46pm 4/29/10 12:46pm

If The Universe Is Expanding, What's It Expanding Into?

Last week the readers of io9 asked their most nagging questions about physics to a real-live physicist. The first question: What is the Universe expanding into? » 4/28/10 12:33pm 4/28/10 12:33pm

Ask A Physicist Any Question You Want About The Universe

This weekend you can ask a real, live physicist (me) any question you like - nothing is too stupid, or too weird. And next week, you'll get answers! » 4/23/10 4:30pm 4/23/10 4:30pm

To the Writers and Director of "Hot Tub Time Machine," From A Physics…

Noted time-travel expert Dave Goldberg, a physics professor at Drexel University, just saw Hot Tub Time Machine and was - disturbed. Here he explains the "egregious number of inviolable paradoxes" in the film, in an open letter to its creators. » 3/29/10 5:14pm 3/29/10 5:14pm