Tag Archives: relativity

Could photons have mass?

In response to my column the other day about whether or not neutrinos could travel faster than light, several of you raised the possibility that: It could simply mean that neutrinos have less mass than photons, so that the true … Continue reading

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Faster than light neutrinos? A quick calculation

A number of people on twitter and elsewhere (including my grad student, Austen) alerted me to an interesting story making its way across the interwebs. A number of sources have reported on a press release put out by the OPERA … Continue reading

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Ask a Physicist: What are your prospects for getting a faster than light drive?

My latest column is up! This is a bit different than my normal fare, since I’m trying to tackle the sci-fi side of things head on. However, it’s entirely like my normal fare in that I end up being a … Continue reading

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I get tweets: How close can you get to the speed of light?

As I hope you know by now, I’m on twitter, and you should totally follow me. While it’s not always a great idea to ask physics questions in tweets (as 140 character answers are unlikely to be informative), a follower … Continue reading

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Ask a Physicist: Can you surf a gravitational wave?

Hurray! After an extended summer hiatus, my Ask a Physicist series is back on io9. This week I’m addressing a bunch of questions about gravitational waves, including why they’re so hard to detect, what they do, and why it’s really … Continue reading

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I get email: Why doesn't a black hole get infinitely massive?

Greetings, relativists. I got an email from a former high school science teacher named Jeffrey that I thought would be fun to do here, rather than in the column. This is a fair bit more mathematical than even my normal … Continue reading

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Ask a Physicist: What's so scandalous about a naked singularity?

Greetings, black hole buffs! My latest column is up, and it’s all about naked singularities. You should check it out and of course, send me more questions. -Dave

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I get email: Time and Gravity

Every now and again, I like to share fun questions that aren’t right for the column, but which you guys might find interesting. For example, check out this, this, or this. As I’ve done in the past, I’m going to … Continue reading

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How long do you have to rescue someone from a black hole?

Forever, and if you hold tight for a bit, I’ll explain why. I’ve been teaching a grad course in general relativity this term, and I’ve been having the time of my life. While my own work in gravitational lensing uses … Continue reading

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Universal Misconceptions #1: The expansion of time

I get a fair amount of email in response to my io9 columns. My latest one, on distance scales in the expanding universe, resulted in more than its fair share. I thought it might be useful to write a few … Continue reading

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