This rocks. Totally out of this world.
Mercury travels behind our celestial sphere on a short leash, its short orbit obscuring it from view thanks to the Sun’s intense light. Only during moments of twilight, in the time between when the solar disk has sunk and Mercury trails behind it, is the solar system’s smallest planet visible, and only then during certain times of year.
Here it is captured by Juan Carlos Casado during the month of March 2000, its fleeting hop above the horizon tracked in several combined photos.
In fact, the planet’s name itself derives from the god Mercury’s fleeting and erratic nature.
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.
Imagine a Living Mars
Mars was likely not always the desolate, red-rocked planet that we see today. The Curiosity rover has found what appear to be water-smoothed pebbles, shaped by ancient rivers of flowing water. Curiosity and previous missions have also seen footprints of alluvial fans and river deltas, sure signs of a previously wet world.
Software engineer Kevin Gill has taken those observations to the next level with these simulations of a “living” Mars, covered with seas and lakes and teeming with vegetation and clouds. He used a survey of Martian terrain and elevation, plugged in a sea level to form oceans, and then painted the clouds and terrain as it might look or have looked.
It’s definitely more an exercise in imagination than in reality, as there’s no indication of past forests or marshy plains on the red planet, but it’s an informed imagination, a realization of a planet’s possible rich past or terraformed future.
Through the eyepiece of an optical telescope, you see something right in front of you, and your brain says, there it is: a jellybean, four feet away. Of course, Neptune is 17 times the mass of Earth and far-flung as it gets, but that doesn’t compute. It might be the farthest thing you’ll ever see, but it looks so close, and in the absence of contextual clues, the ordinary functioning of perspective fires and misses.
And so your awe is self-inflicted. Your awe is one you name to yourself. You almost have to say it out loud, “that’s Neptune,” forcing the cognitive dissonance into place. Once there, accepting that your mind has seen farther than biological limitation is its own challenge; the implications take their time unfolding.
A day in the year of the life of the solar system …
While the animation above is pretty sweet, you’ll really want to go play with the interactive version of this solar system simulator.
You can punch in any year, and let the orbits proceed fast or slow. Use it to learn how the planets align (and don’t), how different bodies orbit, or as an excuse to stare at your screen with your mouth open in amazement. You can even click the “Tychonian” button to see what an Earth-centric solar system would look like! Go ahead, punch in any year in the past or future, and see what the solar system looked like on a given day.
(via Dynamic Diagrams)
PLANETCOPIA - Earth and Other Planets Re-imagined
This home we call Earth? Well, it’s the only home we know. But who among us, I ask, has not wondered what this planet would look like, say, if Antarctica was not an actual landmass, or if all the continents were upside-down? Even XKCD has wondered such things, when Randall showed us what an Earth with 90˚-rotated continents would look like.
Chris Wayan is someone who, until 2010 at least, actually made such worlds. He would envision a different scenario for Earth or another planet, find a globe, sand it flat and then (re-)build the new planet from scratch. This is no haphazard guessing-game, though. It’s not pin-the-continent-on-the-planet. Detailed predictions and calculations are made, involving orbit, atmosphere, reflection, currents, total water, modified tectonics … even biology. Here’s more about his process.
Then the new planet is sketched, sculpted, and the tour commences! I can barely fathom the planning, research and creativity that goes into these. Some that I have included above (clockwise from top left):
- Dubia - A future Earth, showing the effects of twice the atmospheric carbon dioxide that we have today. The name is a not-so-subtle poke to a certain climate-denying former president. Note the 110-meter rise in sea levels.
- Siphonia - An Earth where 90% of the water has been sucked up by thirsty alien invaders. The highlands are even higher and colder.
- Mars terraformed - Picture Mars a thousand years in the future, after colonization and terraforming. Massive oceans and huge, ice-tipped volcanoes abound.
- Turnovia - It’s Earth, flipped on its head. Easy one, right? Not so fast. Our rotation still continues in the direction we are used to now, which changes everything in terms of weather.
There’s more Earths, an uncovered Venus, and even a Europa or two. Awesomely cool stuff. Go check it out.
Planets viewed from Earth as if they were at the distance of our moon
Of course, they forget to mention that as Jupiter rolls by the gravitational balance on Earth would be completely disrupted, sucking our crust and oceans upward to such a degree that we would instantly be both flooded and earthquaked to death, depending on what side of the planet you were on.
What a night sky, though!
Mapping Mars: From Canals to Curiosity
Mars, in Roman mythology, was second only to Jupiter in power and the awe of mankind. Our obsession with the rusty orb orbiting just beyond our own planet is a long one. Today we are landing automobile-sized robotic science labs on its surface to investigate whether the Mars of yesteryear had ingredients that could have supported life.
But it wasn’t that long ago that detailed observations of even the nearest planets were nearly impossible. Before modern photography, astronomers could only draw their observations, and primitive optics made it very hard to get detail through the interference of Earth’s atmosphere. That’s why, until the late 1920’s, there was a heated debate about whether Mars was home to a series of canals, clouds, vegetation, and what was thought to be animal life.
Astronomer Percival Lowell famously (and incorrectly) interpreted a Italian astronomer Giovanni Schiaparelli’s notes of “canali” (channels) as the english word “canal”. This myth of “Martian canals” and the jungles and climate system they supported lived on until the late 1920’s when it was settled that Mars had a very faint carbon dioxide-rich atmosphere.
The photos above, from Lowell’s telescope, show how difficult early Mars observations were. They come from this amazing 1921 collection of planetary photography. A healthy reminder that our interpretations of science, no matter how advanced we may think we are, are only as good as our ability to discern detail and collect good information.