May 12, 2007

New Mission Could Find Star Trek’s Planet Vulcan

All right, this article from NASA is totally pandering to my Star Trek geekiness. I know I'm being manipulated, but I just… can't… resist. According to NASA, their upcoming SIM PlanetQuest mission should be able to find Star Trek's planet Vulcan. You know, Spock's home?

Okay, I'll try and put this into some kind of scientific justification. The SIM PlanetQuest is a new mission in the works at NASA. If all goes well, and it doesn't befall the fate that struck the Terrestrial Planet Finder, it will launch into an Earth-trailing solar orbit. Once fully operational, it'll be able to detect potentially habitable planets as small as the Earth around nearby stars.

Here's the Star Trek angle. One of the stars that it'll be able to detect Earth-sized planets around will be 40 Eridani, a triple star system located about 16 light-years from Earth. In the Star Trek universe, the planet Vulcan, home of Spock, orbits the star 40 Eridani A, which is part of this system. So, if all goes well, SIM PlanetQuest will be able to find an Earth-sized world, in the habitable zone around 40 Eridani A. It'll find Spock's homeworld, get it?

If the Terrestrial Planet Finder does get brought back from canceled status, it'll be able to take this research to the next level, and actually search for signatures of life around any worlds which are discovered.

Original Source: NASA News Release

Organic Chemicals Found in Titan’s Atmosphere

Since the twin Voyager spacecraft flew past Saturn's moon Titan, Scientists have been excited about what its hazy atmosphere can tell us about the earliest days of our own planet. The Voyagers discovered that Titan's atmosphere is swirling with hydrocarbons and other complex organic molecules that could be the building blocks of life. The latest findings from NASA's Cassini spacecraft have uncovered these organic molecules floating higher in Titan's atmosphere than scientists originally thought possible.

This latest research has been published in the May 11, 2007 edition of the Journal Science. It shows that these organic aerosols, called tholins, have been found in altitudes higher than 1,000 kilometres (620 miles) above the surface of Titan. And these molecules are formed differently than how scientists originally believed.

This inquiry is important because the Titan's environment is thought to be very similar to the Earth's early history, before the first life formed. A similar process could have happened here.

Original Source: SwRI News Release & UniverseToday

May 11, 2007

Maximizing Survival Time Inside the Event Horizon of a Black Hole

Here's a scenario that will face many of us in the far future. You're hurtling through the cosmos at nearly the speed of light in your spaceship when you take a wrong turn and pass into the event horizon of a black hole. Uh oh, you're dead - not yet, but it's inevitable. Since nothing, not even light can escape the pull from a black hole once it passes into the event horizon, what can you do to maximize your existence before you join the singularity as a smear of particles?

Physicists used to think that black holes were sort of like quicksand in this situation. Once you cross the event horizon, or Schwarzschild radius, your date with the singularity is certain. It will occur at some point in the future, in a finite amount of proper time. The more you try to struggle, the faster your demise will come. It was thought that your best strategy was to do nothing at all and just freefall to your doom.

Fortunately, Geraint F. Lewis and Juliana Kwan from the School of Physics at the University of Sydney, have got some suggestions that fly in the face of this stuggle = quick death hypothesis. Their paper is called No Way Back: Maximizing survival time below the Schwarzschild event horizon, and it was recently accepted for publication in the Proceedings of the Astronomical Society of Australia.

When an unlucky victim falls into the event horizon of a black hole, they will survive for a finite amount of time. If you fall straight down into a stellar black hole, you'll last a fraction of a second. For a supermassive black hole, you might last a few hours.

Due to the tremendous tidal forces, an unlucky victim will suffer spaghettification, where differences in gravity from your head to your feet stretch you out. But let's not worry about that for now. You're trying to maximize survival time.

Since you've got a spaceship capable of zipping around from star to star, you've got a powerful engine, capable of affecting your rate of descent. Point down towards the singularity and you'll fall faster, point away and you'll fall more slowly. Keep in mind that you're inside a black hole, flying a spaceship capable of traveling near the speed of light, so Einstein's theories of relativity come into play.

And it's how you use your acceleration that defines how much personal time you'll have left.

In a moment of panic, you may point your rocket outwards and fire it at full thrust, keeping the engine running until you arrive at the central singularity. However, Lewis and Kwan have demonstrated that in the convoluted space-time within the event horizon, such a strategy actually hastens your demise, and you'll actually end up experiencing less time overall. So, what are you to do? Lewis and Kwan have the solution, identifying an acceleration "sweet-spot" that gives you the maximal survival time. All you have to do, once across the event horizon, is fire your rocket for a fixed amount of time, and then turn it off and enjoy the rest of the fall.

But how long should you fire your rocket for? Lewis and Kwan show this is a simple calculation involving the mass of the black hole, how powerful your rocket is, and how fast you crossed the event horizon, easily doable on a desktop computer.

Here's another analogy from Lewis:

"Consider a race to the centre between a free faller and a rocketeer. Suppose they cross the event horizon together holding hands. As they cross, they start identical stop watches. One falls inwards, while the other accelerates towards the centre for a little, then swings their rocket round and decelerates such that the free faller and the rocketeer meet and clasp hands again just before hitting the singularity. A check on their stop watches would reveal that the free faller would experience the most personal time in the trip. This is related to one of the basic results of relativity - people in freefall experience the maximum proper time."

So now you know. Even after you've fallen into the black hole's event horizon, there are things you can do to lengthen your harrowing journey so that you get to experience more time.

Time to you can use to deal with your spaghettification problem.

Source: Arxiv research paper & UniverseToday