Earth… our home planet, a brilliant “blue marble” tirelessly turning through space on an endless journey around the Sun and across the galaxy. Basically a ball of molten rock and metal, its relatively thin crust is mostly covered by a sea of liquid water as well as wrapped in a sea of air… and it’s the complex interaction between all of these things that have allowed life to evolve, thrive, and — so far, anyway — continue to exist on this one particular world.
But how exactly does this work? How, and why, do all of these different factors combine to make a habitable planet? Energy from the Sun, the movement of the atmosphere, the planet’s rotation, the constant churning of ocean currents, the upwelling of materials from deep inside the Earth… all of these play essential roles every day in the survival of nearly every living thing on our planet — including us. To truly understand life on Earth, we must first understand the complex interactions of these forces, and more.
Luckily we have satellites, our “eyes in the sky” that let us look at the entire world on a daily basis and measure and monitor many different processes like never before, letting us see the otherwise invisible big picture of Earth From Space.
An incredible 1,200-mile-wide vortex of spiraling clouds swirling above Saturn’s north pole is seen in all its glory in this stunning image from NASA’s Cassini spacecraft, originally captured last year but recently released by NASA on April 29.
Taking advantage of a new orbital trajectory that puts it high above Saturn’s rings and poles, Cassini acquired the near-infrared images used to make this composite back on Nov. 27, 2012. The resulting image is false color — our eyes aren’t sensitive to those particular wavelengths of light — but still no less amazing!
NASA’s Cassini spacecraft has provided the first direct evidence of small meteoroids breaking into streams of rubble and crashing into Saturn’s rings.
These observations make Saturn’s rings the only location besides Earth, the Moon and Jupiter where meteor impacts have been observed as they occur. The meteoroids at Saturn are estimated to range from about one-half inch to several yards (1 centimeter to several meters) in size.
“These new results imply the current-day impact rates for small particles at Saturn are about the same as those at Earth — two very different neighborhoods in our solar system — and this is exciting to see,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “It took Saturn’s rings acting like a giant meteoroid detector — 100 times the surface area of the Earth — and Cassini’s long-term tour of the Saturn system to address this question.”
A rain of ionized water molecules falls into Saturn’s upper atmosphere from its rings, researchers from England’s University of Leicester have found. Using images from NASA’s Voyager spacecraft and more recent near-infrared observations from the Keck Observatory in Hawaii, it has been found that dark bands seen across Saturn are actually the “rain shadows” of particles from the rings interacting with the planet’s atmosphere, effectively cooling it and reducing heat emissions in those areas.
“Saturn is the first planet to show significant interaction between its atmosphere and ring system,” said James O’Donoghue, the paper’s lead author and a postgraduate researcher at Leicester. “The main effect of ring rain is that it acts to ‘quench’ the ionosphere of Saturn. In other words, this rain severely reduces the electron densities in regions in which it falls.”
According to research by NASA astronomers using the next-generation optics of the 10-meter Keck II telescope, Jupiter’s ice-encrusted moon Europa has hydrogen peroxide (aka H2O2) across much of the surface of its leading hemisphere, a compound that could potentially provide energy for life if it has found its way into the moon’s subsurface ocean.
“Europa has the liquid water and elements, and we think that compounds like peroxide might be an important part of the energy requirement,” said JPL scientist Kevin Hand, the paper’s lead author. “The availability of oxidants like peroxide on Earth was a critical part of the rise of complex, multicellular life.”
How far away is Mars? The exact answer varies, of course, as both it and our planet are constantly moving along their own orbits around the Sun. At the time of this writing Mars is on the other side of the Sun from us, 2.413 AU away as the space crow flies (which equates to nearly 361 million km or 224.3 million miles) and, back in 2003, Mars and Earth were at their closest in 50,000 years at a scant 56 million km/33.9 million miles apart. So on average, Mars is about 225 million km/140 million miles from Earth. Give or take a few.
For the sake of convenience, let’s say we reduced Earth to a sphere 100 pixels in diameter and you could travel outward at a velocity of 7,000 pixels/second (which is, to scale, about 3 times light speed) how far would Mars be? Find out here.
Think the Milky Way is a big place? Think again — check out this graphic by Arecibo astrophysicist Rhys Taylor, which neatly illustrates the relative sizes of 25 randomly-selected galaxies using images made from NASA and ESA observation missions. It even includes a rendering of our own remarkably mundane galaxy at the center for comparison.
(Warning: this chart may adversely affect any feelings of galactic superiority you may have once held dear.)