Wednesday, April 25, 2007

Huge Discovery Today- Gliese 581 C

Artist's rendering
  • Rocky composition
  • Smallest extra solar planet found to date (announced today)
  • 50% more mass than Earth.
  • Average temperature (0-40 C)
  • Companion star: Gliese 581 (M class red dwarf star 50 times dimmer than our sun)
  • 15 times closer to companion star than Earth. (6 million miles)
  • Solar year: 13 days
  • Distance from Earth: 20.5 light years. (That's actually in our neighborhood as long as your not trying to go there)
  • May be completely covered with water.
  • May harbor life.


Chavo said...

I can't calculate the math, but how long in earth time would a trip to this planet take? A round trip takes 42 years, plus the time you take to hang around. But you're travelling at the speed of light, time seems normal if you're on the spacecraft, what happens on earth? According to the theory of relativity, the round trip wouldn't be fifty years but some order of magnitude larger. Correct?

Apollo said...

For the traveler, near the speed of light, the trip would be over quickly. However, the observer could observe the ship for the duration of the light year trek in Earth time. (i.e. 20+ years)

It all depends on the observer (i.e. who is taking the measurement.

The dilation of time and contraction of distance can be accounted for using a fairly simple formula originated by Lorentz.

Here's a good link:

This phenomenon is known as the Lorentz Contraction.

The inverse of this function yields the time dilation and hence, the time passed for both the observer and the traveler (traveler being much less the faster you go)

here's link that demonstrates the Lorentz contraction of time for the traveler.

Have fun digesting this stuff :-)

Apollo said...

Go here for a Lorentz calculator for:

Length contraction

Time dilation

Relativistic Mass

Chavo said...

or try this site:

Apollo said...

This site has an even better one with real time animation:

Chavo said...

This site:

can calculate the time it takes to reach an object in space relative to the observed time on earth.

Basically, to reach this new planet it takes 22.4 earth years one way, while to the traveller it takes 6.1 years. Consequently, upon his return to earth he has aged 12.2 years while his compatriats at Mission Control (who've long since retired) have aged 44.8 years.

Chavo said...


Its Inhabitants Are Easygoing and Sociable, but May Also Be Indecisive and Changeable Earth-Like Planet Discovered in Libra--headline, NPR Web site, April 25

Hat Tip: James Taranto