|—||Neil Tyson (via nathanielstuart)|
Billions and Billions … of Planets
There are infinite worlds both like and unlike this world of ours. For the atoms being infinite in number, as was already proven, (…) there nowhere exists an obstacle to the infinite number of worlds. - Epicurus (341-270 B.C.)
Where is everybody? - Fermi’s Paradox, ca. 1950
In a universe of infinite possibilities, everything is not only possible, it’s probable. Of course, the universe isn’t really infinite. But in certain respects, it is big enough and contains so many of certain “things” that what is possible begins to get awfully close to what is probable.
So it is with planets, and perhaps life outside of our solar system.
But first, the news! NASA has announced its newest estimate for the number of planets in the Milky Way galaxy. Based on observations of a known system of extrasolar planets (those outside our own solar system), they determined there are at least 100 billion planets in our galaxy. At least. That means there is perhaps one planet for every star! That number doesn’t even take into account the existence of forever-alone rogue planets, wandering lifeless and free of warm parent stars.
Which brings us back to Fermi’s Paradox. Lower estimates say there are ~2 x 1011 stars in the Milky Way (200 billion). If we do some more extrapolation and guesstimation, we can say there are roughly 7 x 1022 stars in the known universe … 70 thousand million million million stars. If most galaxies are like the Milky Way, then that means each star would have one planet, on average. Now let’s say that a tiny fraction of those are at the right distance from their stars and composed of the right stuff and subject to a host of other perfect conditions, and they may be capable of supporting life. That’s still a ridiculously huge number.
So where is everyone?! It stands to reason, by odds and probability, that after 13.7 billion years of cosmic evolution we can’t be the sole special case in which that perfect storm of cosmic ingredients came together to produce life. That’s what bugged Fermi, and in a way, Epicurus before him.
NASA’s Kepler project continues to identify and track extrasolar planets, accompanied by occasional announcements of Earthiness. Yet what we have discovered is a fraction of a fraction of a fraction of the planets in but our galaxy. the odds of any of them harboring life is immensely small, while the chance that life exists somewhere remains likely … to people like me, anyway.
To say that Earth is unique in the universe would be to say that one grain of sand on Earth (~1018 of them, by the way) is somehow more special than all the others. Of course, if we asked the grain of sand, it might say “Yes, I am special!” because it is the best grain of sand it knows of. So it is with us, waiting alone in the “biggitude” of it all, to find out if we’re special.
The predicted Andromeda–Milky Way collision in approximately 4 billion years.
The universe may grow like a giant brain, according to a new computer simulation. The results, published Nov. 16 in the journal Nature’s Scientific Reports, suggest that some undiscovered, fundamental laws may govern the growth of systems large and small, from the electrical firing between brain cells and growth of social networks to the expansion of galaxies. “Natural growth dynamics are the same for different real networks, like the Internet or the brain or social networks,” said study co-author Dmitri Krioukov, a physicist at the University of California San Diego. The new study suggests a single fundamental law of nature may govern these networks, said physicist Kevin Bassler of the University of Houston, who was not involved in the study. [ What’s That? Your Physics Questions Answered ] “At first blush they seem to be quite different systems, the question is, is there some kind of controlling laws can describe them?” he told LiveScience. By raising this question, “their work really makes a pretty important contribution,” he said. (via Universe may grow like a giant brain - Technology & science - Science - LiveScience | NBC News)
|—||Brian Cox (via expose-the-light)|
Are we sure there is nothing over there?
NGC 4565: Galaxy on the Edge
Credit & Copyright: Roth Ritter
2011 Nobel Prize: Dark Energy feat. Sean Carroll
Guest narrator Sean Carroll of Caltech describes dark energy and the acceleration of the universe, the discovery of which was awarded the 2011 Nobel Prize in Physics on October 4th.
Space: You Are Here poster series by Mike Gottschalk
Gravitational lensing is so much fun! (it really is :P)
Be warned, the “Awesome Sagan Factor” on this is off the charts, so sit down and prepare yourself to be wowed. Wow.
The beauty of what surrounds us is so overwhelming that it leaves us without words or makes us blind