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Showing posts with label planetary system. Show all posts
Showing posts with label planetary system. Show all posts

Monday, July 25, 2016

Time Troubles

I just calculated something out, and the result, well, is rather depressing... This is a photo of a portion of the Milky Way galaxy. Each dot in the photo is a star. More than 50% of all stars have planetary systems such as our Solar System. The nearest star to Earth is Proxima Centauri, one of three stars in the Alpha Centauri system. Proxima is 4.2 light-years away. There are 5.8 trillion miles in one light-year (or 5.8 thousand billion, or, if you prefer, 5,800,000,000,000), so we're dealing with about 25 trillion miles.

A view of the Milky Way toward the  constellation Sagittarius. Source: Wikipedia
A view of the Milky Way toward the  constellation 
Sagittarius.  Source: Wikipedia.

OK, That's bad enough. But let's say we decide to send an astronaut to Proxima Centauri, in the fastest rocket, at the fastest manned flight speed we've been able to attain (that would be the Saturn V, a 3-stage booster used for the Apollo program - a top speed of 26,000mph). Now, even if we could send that astronaut at the speed of light (exactly 186,282.3976 miles per second, in vacuo), it would take her (or him), 4.2 years to complete the trip as measured by an observer on Earth (because of the relativistic effects of time dilation, only a few days will have passed, as judged by the astronaut - but we're not going there! - not here - that's another story, for another time). But, now for the sad part...

At 26,000 mph, 0.000037% the speed of light, the trip would take 116,000 years. That's one-way. Our astronaut would be, long ago, fossilized. Time dilation is negligible here, so we don't need to factor it in at such low velocities. One of the nearest stars with a known planetary system is around 15 light-years. So, if we have cosmic relatives somewhere out there within that range, the chances of meeting up with them are absolutely nil. These distances and times involved are the reason most astronomers don't believe in UFOs, or that we're being visited by extraterrestrials. YES, WE DO BELIEVE they exist, but not that we're being visited by them on any regular basis. The situation isn't much better with radio communications. Even though radio waves travel at the speed of light, transmission to any hypothetical beings in, say, the Fomalhaut planetary system will take 15 years. That's one-way. Telepathy, should it prove to be viable, would be much more economical, assuming it to be instantaneous. Another plausible answer might be to travel through wormholes, to beat the clock, but, for now, they're hypothetical. Other than that, due to the restrictions on speed, we may never meet anyone else; we might always be alone - surrounded, perhaps, by a myriad of Celestial Peoples - and yet alone, regardless.

Dale Alan Bryant
Senior Contributing Science Writer
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Saturday, August 22, 2015

Twinkle, Twinkle, Little, Red Star

This is a COMSIM of the recently discovered planetary system, Gliese (GLEE-ZUH) 876, a red, type-M star with some similarities to the Sun (type-G), 15 light-years away, with three planets in orbit around it. It was discovered by the Kepler Mission Space Telescope.

As can be seen, planets do not necessarily orbit their host stars in an orbital plane, perpendicular to the star's axis of rotation, in the way that the planets of our solar system do. This came as a bit of a surprise to me when I found out that a high percentage of exo-planetary systems actually exhibited this arrangement (I don't have that figure with me at the moment).

Illustration of the Gliese 876 Planetary System.
Illustration of the Gliese 876 Planetary System.

The green disk represents the extent of the habitable zone (popularly referred to as the 'Goldilocks Zone'), of Gliese 876, in which, two planets, "876 b" and "876 d", partially occupied, in eccentric orbits, relative to each other. The zone is shown at an angle perpendicular to Gliese 876's axis of rotation.

The parent (host) star of this system, Gliese 876, is an 11th-magnitude star. This means that, although the system is 87,000,000,000,000 (87 trillion) miles away - it can actually be seen in a medium-sized (6" aperture) telescope. Take a look!

Dale Alan Bryant
Senior Contributing Science Writer
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