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Astronomers Find Sun's Twin
mroch writes "Space.com is reporting that astronomers may have found a solar twin -- a star almost exactly like our own Sun. Interesting tidbits from the article include: "The star, 18 Scorpii, sits about 47.5 light-years away in the constellation Scorpio, and has long-been suspected of being Sun-like. [...] The star burns slightly hotter than the Sun, at 5,789 degrees Kelvin compared to 5,777 degrees. It appears to rotate slightly faster than the Sun, taking 23 days to complete a rotation rather than the Sun's 25." It boggles my mind to think that we can measure temperature that exactly from 279,000,000,000,000 miles away, and that they are complaining over a 12-degree difference."
Distance actually does not matter with respect to the method used to measure the temperature, as long as you have enough light, and there is no disturbing medium in between. Both conditions seems to be met.
IIRC, the temperature is measured by the colour of the sun. That doesn't change the further away you get, so its just as accurate over long distances as short. However, there is the problem of dopler shift if the stars are moving away/toward each other.
"When I grow up, I want to be a weirdo"
What do we know about that star and its surroundings? Is it likely to have inhabitable planets or is it bathed by lethal radiation from neighboring novas?
How long before we can actually check these stars for Earth-like planets? Last I heard, we now had the ability to detect planets slightly smaller than Jupiter. Will we find, or even see, an inhabitable planet within a few decades?
Yeah, there's much difference between a delta of 12 degrees kelvin and 12 degrees celcius. OTOH, you USians (and UKians?) with your funny measurements probably measure temperatures in ounces, feet or hands or something. :)
Free as in mason.
Actually, 12 a degree difference in Kelvin is the same as a 12 degree difference in Celcius.
Really, you shouldn't use the word 'degree' with the work 'Kelvin' as in the case used in the Story. It's preferable to write simply 5789 Kelvin.
From The U.S. Metric Association
The kelvin (K) temperature scale is an extension of the degree Celsius scale down to absolute zero, a hypothetical temperature characterized by a complete absence of heat energy. Temperatures on this scale are called kelvins, NOT degrees kelvin, kelvin is not capitalized, and the symbol (capital K) stands alone with no degree symbol. [In 1967 the new official name and symbol for "kelvin" were set by the 13th General Conference on Weights and Measures (CGPM).]
I like David Nash's list of 50 nearby sunlike stars within 50 light years.
18 Scorpii is on there, as is the infamous Tau Ceti. 18 Scorpii was one of the four closest matches.
Binary geeks can count to 1,023 on their fingers
Really, you shouldn't use the word 'degree' with the work 'Kelvin' as in the case used in the Story. It's preferable to write simply 5789 Kelvin.
Since we're nitpicking... its kelvin, not Kelvin.
does anyone here know what advances would be necessary to send probes & recover data about nearby star systems? Ion drives seem to be moving in the right direction, to use a phrase, but would they be sufficient in longevity & speed to make a multi-light year journey? And what sort of remote communication would be possible at such distances?
A corollory to this is, does anyone know what (if any) systems the Voyager spacecraft are going to encounter, and when?
Astronomers look at the spectrum of the star--the relative intensities of each wavelength of light produced by the star's heat. Assuming the star is a black-body radiator (which isn't totally true, but pretty darn close), using first principles you can solve for the temperature of such and object as a function of the peak wavelength of light radiated. See "Thermal Physics" by C. Kittel and H. Kroemer for a better discussion.
Also, single wavelength filters (like your green sheet of plastic) aren't a natural byproduct of nature, and wouldn't be found between here and the aformentioned star. What would would find, however, is interstellar dust, or clouds of hydrogen, helium, lithium, and other light elements. When the light passes through these clouds, certain frequencies of light are absorbed, and certian frequencies are flouresced, but these frequencies are predictable, and the overall shape (and especially the peak) of the spectrum is not changed beyond recognition. "Introduction to Quantum Mechanics" by D. Griffiths and "Introduction to Astronomy and Astrophysics" by Zeilik and Gregory should help you out with spectra and spectral lines.
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What do we know about that star and its surroundings? Is it likely to have inhabitable planets...
As cool as it is to find a star that's a twin to ours, it's incredibly unlikely that we'll find a planet even remotely similar to Earth.
For one thing, the article notes that 18 Sco is 4.2 billion years old, while Sol is 4.5 billion years old. If everything else were exactly equal, it would be like stepping back 300 million years back in time. A quick Google finds that one of the more complex forms of life found 300e6 years ago on this planet was the Velvet Worm -- not a species known for its technology.
But even that is unlikely, given the Earth's unusual formation. This planet has an unusual mix of minerals on its crust, plus plate tectonics to keep them mixed, and an iron core that's magnetic enough to keep out the sun's ionizing radiation. Plus, a moon big enough to stir up the oceans, and a tilt to generate asymmetrical solar heating... and all that apparently due to a one-in-a-million collision between a proto-Earth and a Mars-sized planet not long after Sol formed.
I can't find the quote, but someone calculated the odds of finding another sentient species as tiny. It's not that it doesn't develop elsewhere in the galaxy... there are billions of chances, so surely more than one came up all 7s. It's just that the distances are so vast, and the chances of favorable development so small, that entire civilizations (or species) could rise and fall by the time their transmissions reach another civilization's satellite dishes.
But still, at less than 50 light years, it would only take a few hundred years to get there and back. Are the generation ships ready yet?
Stressed? Me? Of course not. Stress is what a rubber band feels before it breaks, silly.