Slashdot Mirror
Three Neptune-sized Planets Found Nearby
WillAffleckUW writes "CNN reports the discovery of three Neptune-sized planets found in orbit around a sun 41 light years away. The star they orbit is similar to our Sun, and the planetary distribution is probably similar to our Solar System. Recent observations by NASA's Spitzer Space Telescope last year revealed that HD 69830 also hosts an asteroid belt, making it the only other sun-like star known to have one. No word on if they have habitable moons, or monoliths yet."
As opposed to something that is over 7,000 - 10,000 light years away, 41 isn't very far. I mean it's no Alpha Centauri, but it's close in astronomical terms.
...and that's the way the cookie crumbles.
Since Neptune and Uranus are about the same size, it looks like the units were chosen precisely to avoid that particular lame joke. =)
Space is big. Really big. You might think it's a long way to the chemist on the nearest non-Milky Way Nuptune-sized planets 41 light years away, but that's peanuts compared with space
Good luck sometimes arrives disguised as bad
Question: What is a light-year and how is it used? Answer: A light-year is a unit of distance. It is the distance that light can travel in one year. Light moves at a velocity of about 300,000 kilometers (km) each second. So in one year, it can travel about 10 trillion km. More precisely, one light-year is equal to 9,500,000,000,000 kilometers. Why would you want such a big unit of distance? Well, on Earth, a kilometer may be just fine. It is a few hundred kilometers from New York City to Washington, DC; it is a few thousand kilometers from California to Maine. In the Universe, the kilometer is just too small to be useful. For example, the distance to the next nearest big galaxy, the Andromeda Galaxy, is 21 quintillion km. That's 21,000,000,000,000,000,000 km. This is a number so large that it becomes hard to write and hard to interpret. So astronomers use other units of distance. In our solar system, we tend to describe distances in terms of the Astronomical Unit (AU). The AU is defined as the average distance between the Earth and the Sun. It is approximately 150 million km (93 million miles). Mercury can be said to be about 1/3 of an AU from the Sun and Pluto averages about 40 AU from the Sun. The AU, however, is not big enough of a unit when we start talking about distances to objects outside our solar system. For distances to other parts of the Milky Way Galaxy (or even further), astronomers use units of the light-year or the parsec . The light-year we have already defined. The parsec is equal to 3.3 light-years. Using the light-year, we can say that : * The Crab supernova remnant is about 4,000 light-years away. * The Milky Way Galaxy is about 150,000 light-years across. * The Andromeda Galaxy is 2.3 million light-years away.
It wasn't that long ago (err, wow, 10 years, maybe that's long) that the first extrasolar planet was discovered. I still remember that news announcement I watched on TV...
Anyway, since the discovery of those 3 planets, another planet has been found. Check out the exoplanet encyclopedia (my favourite exoplanets site). It has a catalog with all the data of those planets, some with uncertainty factors. Discovery method, size, catalogue number, the whole lot. Try chucking all that into a spread-sheet, and plot some scatter graphs. Should be a lotta fun. The last time I tried this, it was a bit problematic because the masses are not really known (for planets discovered using spectral shifts), but are merely minimum (maximum?) limits only. But still, an order of magnitude plot could be fun.
Anyway, the 3 planets are already in the catalogue under HD 69830. Don't forget to check out this one as well. Exciting times. I look forward to 200 planets!
Wait, did you just say radio waves don't travel at the speed of light? Hmm, yes you did. FYI, radio waves are light.
I reckon aliens would have a hard time picking up TV stations from mars, never mind light years away.
Assume that the aliens have a radio telescope that is comparable to the one at Arecibo. I don't have numbers on its sensitivity after recent upgrades, but a ball-park figure I have heard is that it can pick up a cell phone transmission within a sizable part of the solar system near earth.
A rough calculation reveals that perhaps a 10^14 W source at the centre of our galaxy (2.2 x 10^4 light-years away) could be detected by Arecibo. Compare this to terrestrial television (~10^6 W) and radio (~10^5) stations, and you'll find that it could be on the edge of possiblility for Arecibo to pick up TV transmissions from a planet 41 light-years away.
If it weren't for deadlines, nothing would be late.
http://fs4.deviantart.com/i/2004/217/a/2/Death_and _Taxes_____.jpg
- a good link that everybody should see...
Dude, you could at least give some attribution to http://starchild.gsfc.nasa.gov/docs/StarChild/ques tions/question19.html
My business: Farstrider Studios.
Get your ACKs to Mars!