In recent years, astronomers have discovered a variety
of worlds around other stars, but have not encountered a planet remotely
like our own. Our instruments most likely are not sensitive enough
to make such a detection. But wait!! This may soon change.
NASA is launching a mission called Terrestrial Planet Finder, a space
telescope specifically designed to detect another Earth. The odds
are favorable that a survey of approximately 150 nearby stars will reveal
at least one small, Earth-like planet.
If such a discovery is made, what will be the next step?
Will we, like Columbus, long to travel to the new world?
Let's do some computations to see what we are facing.
(Please express answers in scientific notation)
Light travels at a speed of
1.86 x 105 miles per second.
A "light year" is the distance
that light travels in one year.
1. Alpha Centauri, which lies 4.4 light years away, is the
closest star system. It would be a good candidate for discovering an
Earth-like world. The distance to Alpha Centauri is 3,000 times
farther than any space probe has ever traveled.
In miles, how far is the journey to Alpha Centauri?
In miles, approximately how far has the furthest space probe traveled?
The star 55 Cancri, which has three large planets similar to
those in our solar system, is 10 times more distant than Alpha Centauri.
In miles, how far is the journey to 55 Cancri?
Traveling at the speed of light, how long would a journey to 55 Cancri
take (in years)?
3. Robert Frisbee, an engineer who directs advanced propulsion
concepts studies at NASA's Jet Propulsion Laboratory in Pasadena,
California, is attempting to find a way to master interstellar travel.
He is studying five distinct propulsion technologies that could get an
astronaut from here to Alpha Centauri in less than 50 years.
In miles per second, how fast
would the space ship be traveling if the journey to Alpha Centauri is
accomplished in 50 years?
(assuming a constant speed) _____________________________
The star Sirius is 81
trillion kilometers away. In miles, how far is a journey to Sirius?
(1 km = 0.62 mi)
Traveling at the speed of light,
how long would a journey to Sirius take (in years)? _________
is 78 million kilometers from Earth. It has been estimated that the
journey to Mars would take 5 years. How fast, in miles per second,
would the space ship be traveling to arrive on Mars within 5 years?