The majority of physicists say time travel probably won't work (at least in the Hollywood-go-anytime-you-wanna sense). Several time traveler parties have gone famously unattended by time travelers (at least, any willing to fess up about it). In general, science is kind of a buzz-kill on this one.
But if you want some justification for your daydreams, the person to talk to is Ronald Mallett, a theoretical physicists at the University of Connecticut who is most well-known for being the guy who thinks time travel is totally possible. (Mark wrote about him here back in 2007.) In fact, in 2006, Mallett predicted that time travel would be figured out within a decade.
I honestly have not researched this enough to give you my opinion on Mallett's ideas. His fellow physicists have addressed it, though. You can read one response to Mallett at arXiv. All of that is a long, context-relevant introduction to the video above, where Mallett explains his theories. I wanted to post the video because it's interesting and I thought you all would dig it. I'm also interested in the new video series this comes from—EPIPHANY, a daily video about big ideas taken from interviews with journalists, tech thinkers, scientists, and more. Mallett makes an interesting kick off for a series like this.
My hope, though, is that EPIPHANY doesn't only focus on scientific ideas that are kind of on the fringe. There's so many amazing discoveries that have the bulk of evidence behind them, it seems like a waste of a good platform to not cover the stuff that's more likely to be true.
Check out the rest of the EPIPHANY videos. So far, the series includes clips from interviews with Ronald Mallett, Reddit founder Alexis Ohanian, and filmmaker Jason Silva.
Removing Orbital Debris with Lasers. How's that for a great research paper title?
Most of you are probably aware of the existence of space trash—that collection of disused satellites, lost tools, spent rocket boosters, and various other flotsam that is starting to become a physical hazard to the objects we actually want circling the globe in Low Earth Orbit. Currently, we get around the problem (mostly) by attaching bumpers to spacecraft and to the ISS. But there are lots of different ideas for how we could deal with the problem of space junk in a more proactive way.
The team of private and government scientists who wrote this paper want to aim lasers at space junk. But not like you're thinking. Instead of blowing up our trash in a life-size game of Asteroid (something that would really only succeed in creating a lot more, smaller pieces of space junk) the team wants to use laser pulses to alter the momentum of large pieces of junk, slowing those pieces enough that they fall out of orbit and back to Earth.
Such a system could be used to precisely time the reentry of dead satellites and other junk, ensuring that when chunks of metal fall out of the sky they won't be falling on any densely populated regions. That's one of the major benefits to this proposal.
The major detriment: Politics. How do you build a laser big enough to knock space junk out of orbit without convincing half the world that what you've really built is a giant death ray? That's something the authors hope to avoid through international cooperation.
Image: Goddard Celebrates International Observe the Moon Night with Laser Show, a Creative Commons Attribution (2.0) image from gsfc's photostream