Posts Tagged ‘earth’
Time-Lapse ISS Video of Earth Lets You Orbit in HD
The movie starts in the Pacific Ocean and flies over North and South America before sunrise over Antarctica. The neuronal network of nighttime cities is marvelous to behold — not to mention the lightning storms off the southern coast of Mexico and into the Pacific.
It takes roughly a minute to fly from Vancouver Island to the southern portion of Chile. A real latitudinal arc on the ISS takes much longer, of course, but I like this fast view because it’s somewhat humbling — this planet is not really that big. Plus, you get an appreciation for just how much if it is oceans.
Raw data was downloaded from the Gateway To Astronaut Photography of Earth, a Johnson Space Center project. to see even more astronaut images, which should keep you sated until the ISS gets a sometime next year.
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Earth-Generated Panspermia: Scientists Describe How Earth Rocks Could Have Seeded the Rest of the Solar System With Life
Scientists have found several meteorites that originated on Mars or the moon, after being ejected in asteroid collisions, forcefully thrown into space and finally arriving on Earth. It makes sense that the opposite could be true, and that after mega-collisions, some pieces of Earth could be thrown toward Mars or Venus.
But most simulations suggest very few Earth pieces would reach the fourth planet, because they would have a hard time overcoming the gravitational pull of both Earth and the sun. Lots of the ejected particles would actually wind up back on Earth, according to previous studies. Some scientists have even suggested these refugee particles would “re-seed” their home planet.
Now researchers in Mexico have , and they say plenty of Earth bits would indeed make it to Mars — and beyond, all the way to the Jovian system. Mauricio Reyes-Ruiz and colleagues at the Universidad Nacional Autonoma de Mexico ran computer simulations of 10,242 test particles, following their predicted paths for 30,000 years. That’s about as long as scientists think life could survive in space, the authors note.
They ran simulations at five different ejection velocities, from 6.97 miles per second to 10.2 miles per second. They found that at faster velocities, particles are more likely to reach Jupiter than Mars, because of their great speed relative to Mars’ low gravitational pull. The particles also reach Jupiter more quickly, with half making the trip in 10,000 years, the authors write. In one simulation, just one particle reaches Mars, and it takes between 25,000 and 30,000 years to get there.
Even more bizarre, many particles end up traveling past 40 AU, which the authors describe as leaving the solar system.
This is all theoretical, of course — the ejection velocity and the particles’ trajectory would be determined by variables like the size and velocity of the incoming object, not to mention the collision location relative to the spin of the Earth. But it’s an interesting concept — as KFC points out over at , if life persists in space longer than astrobiologists think, life from Earth could still be speeding toward distant worlds.
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Earth May Once Have Had Two Moons That Collided to Form the One We Know
Both moons would have coalesced from the remnants of debris ejected when a Mars-sized object whacked the Earth early in its formation, scientists say. Most moon-formation theories have suggested our sole satellite formed from that chaotic jumble. But a new paper published today in Nature says a tiny Trojan moon, about one-thirtieth the size of the one we have today, survived as well, inhabiting a Lagrange point 60 degrees in front or behind the moon.
The two moons would have existed in peaceful harmony for tens of millions of years, long enough for both moons to almost completely solidify, say Erik Asphaug, a planetary scientist at the University of California, Santa Cruz, and Martin Jutzi, now of the University of Berne. Earth’s gravity would have gradually caused both moons to migrate outward, until the Sun’s gravity started to play a role, according to a . Then the Lagrange point equilibrium would have been disrupted, setting the small moon adrift.
When the moons eventually collided, the smaller moon would have been destroyed, its remnants coating half of the larger satellite. This is a valid explanation for the odd makeup of the moon, Asphaug and Jutzi say. They conducted detailed computer simulations to find out what would have happened.
The visible side is dominated by low-lying lava plains, called maria, which contain potassium, rare earth elements and phosphorus, a compendium known as KREEP. The far side, which was first illuminated by human satellites in 1959, is composed of mountainous terrain with a thicker crust. Other theories have suggested the maria are the result of Earth’s gravity yanking material up from within, leaving the far side unperturbed, or the result of convective action in the moon's mantle. But Asphaug and Jutzi say when the departed small moon made impact, on what happens to be the current far side, it smooshed the KREEP toward the opposite side.
The impact would not make a typical crater, Asphaug explains to Nature — the impact zone was only a little bit bigger than the impactor itself. “The impactor just kind of splats into the cavity,” he said.
It’s an interesting theory in many ways, if only for the idea that the moon once had a smaller sibling, because Earth is the only bemooned body to have just one. Neither Mercury nor Venus has a natural satellite, and Mars has two, Phobos and Deimos. The other planets and non-planets have a bunch — even that we now know about.
Serendipitously, NASA is about to send a pair of twin satellites to map the moon, and study its interior composition. The , which will launch next month, might be able to help answer some questions to test this new theory.
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ISS Will Broadcast First Streaming HD Video of Earth
A Canadian company called UrtheCast (don’t ask us why it’s spelled this way) arranged a deal with Roscosmos, the Russian space agency, to bring two cameras to the International Space Station sometime later this year, where they will be mounted on the exterior. The video will be downlinked to Earth and broadcast online.
One camera will shoot in high-definition, with a frame rate of 3.25 fps, and another will broadcast in lower resolution, offering a three-color image. It will provide the first high-definition continuous video footage of Earth, according to Scott Larson, co-founder and president of UrtheCast, in a promotional video.
The system will work as a sort of mashup between Google Earth and YouTube, Larson says, connecting live footage with maps and other capabilities. Users will be able to pause, rewind and zoom, and view specific times and locations — so long as the ISS was passing overhead at the time.
The camera is made by a UK firm and a Canadian company that worked on the shuttle’s robotic arm provided the software support. UrtheCast is based in Calgary.
UrtheCast hopes to launch the cameras later this year and start broadcasting by early 2012. Watch the dramatic trailer below.
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After Earth: Why, Where, How, and When We Might Leave Our Home Planet
Humanity may have millennia to find a new home in the universe--or just a few years
Why?
Indeed, in 1989 a far smaller asteroid, the impact of which would still have been equivalent in force to 1,000 nuclear bombs, crossed our orbit just six hours after Earth had passed. A recent report by the Lifeboat Foundation, whose hundreds of researchers track a dozen different existential risks to humanity, likens that one-in-300,000 chance of a catastrophic strike to a game of Russian roulette: “If we keep pulling the trigger long enough we’ll blow our head off, and there’s no guarantee it won’t be the next pull.”
Given the risks humans pose to the planet, we might someday leave Earth simply to conserve it.Many of the threats that might lead us to consider off-Earth living arrangements are actually man-made, and not necessarily in the distant future. The amount we consume each year already far outstrips what our planet can sustain, and the World Wildlife Fund estimates that by 2030 we will be consuming two planets’ worth of natural resources annually. The Center for Research on the Epidemiology of Disasters, an international humanitarian organization, reports that the onslaught of droughts, earthquakes, epic rains and floods over the past decade is triple the number from the 1980s and nearly 54 times that of 1901, when this data was first collected. Some scenarios have climate change leading to severe water shortages, the submersion of coastal areas, and widespread famine. Additionally, the world could end by way of deadly pathogen, nuclear war or, as the Lifeboat Foundation warns, the “misuse of increasingly powerful technologies.” Given the risks humans pose to the planet, we might also someday leave Earth simply to conserve it, with our planet becoming a kind of nature sanctuary that we visit now and again, as we might Yosemite.
None of the threats we face are especially far-fetched. Climate change is already a major factor in human affairs, for instance, and our planet has undergone at least one previous mass extinction as a result of asteroid impact. “The dinosaurs died out because they were too stupid to build an adequate spacefaring civilization,” says Tihamer Toth-Fejel, a research engineer at the Advanced Information Systems division of defense contractor General Dynamics and one of 85 members of the Lifeboat Foundation’s space-settlement board. “So far, the difference between us and them is barely measurable.” The Alliance to Rescue Civilization, a project started by New York University chemist Robert Shapiro, contends that the inevitability of any of several cataclysmic events means that we must prepare a copy of our civilization and move it into outer space and out of harm’s way—a backup of our cultural achievements and traditions. In 2005, then–NASA administrator Michael Griffin described the aims of the national space program in similar terms. “If we humans want to survive for hundreds of thousands or millions of years, we must ultimately populate other planets,” he said. “One day, I don’t know when that day is, but there will be more human beings who live off the Earth than on it.”
Where?
Two Planets Discovered Sharing the Same Orbit
It is possible that such a phenomenon could occur when matter around a newborn star forms into planets. In a planet’s orbit around a star, there are two places where a third body can safely orbit. These spots, known as Lagrange points, are 120 degrees in front of and behind whichever body is smaller. The discovered co-orbiting planets, located in the four-planet system KOI-730, are always 120 degrees apart, permanent fixtures in each others’ night skies.
Fifty million years after the birth of our solar system, the moon may have formed from the debris of a collision between Earth and a Mars-sized body named Theia. For this to be true, Theia would have to have hit earth at a relatively low speed. Richard Gott and Edward Belbruno of Princeton University say that this could only have happened if Theia had originated in a Lagrange point. The discovery of the KOI-730 planets shows that it is possible.
Maybe someday these co-orbiters will collide and form another moon. But it won’t happen for some time, as simulations show that the planets will continue to share their orbit for at least 2.22 million more years.
FYI: If I Fell Through The Earth, What Would Happen In The Center?
Just getting to the center of the Earth and surviving is impossible. The Earth’s core is about 9,000°F—as hot as the sun’s surface—and would instantly roast anyone who found himself there. Then there’s the pressure, which can reach roughly three million times that on the Earth’s surface and would crush you. But let’s not sweat the details. Once you arrive in the center of the Earth, the physics gets really interesting.
Understanding gravity, the force of attraction between objects, is going to be key to wrapping your head around what is about to be a bizarre situation. The strength of gravitational attraction is determined by an object’s mass and how close it is to another (more mass and closer together means increased force). The only gravity strong enough for us to feel comes from the Earth’s mass, which is why we feel a downward pull on the surface.
At the center of the Earth, the situation is different. Because Earth is nearly spherical, the gravitational forces from all the surrounding mass counteract one another. In the center, “you have equal pulls from all directions,” says Geza Gyuk, the director of astronomy at the Adler Planetarium in Chicago. “You’d be weightless,” free-floating.
But what would happen if you tried to get out of the center by, say, climbing up a very long ladder that ends in Los Angeles? (For clarity’s sake, let’s assume that the Earth is uniformly dense. It isn’t, but the general trend described here still holds.) At the center, the gravity from the mass beneath your feet all the way to the other side of the Earth, the Indian Ocean, will be “pulling” you down, even as the mass above your head is “pulling” you up, toward L.A. After climbing a few rungs, the total pull you feel down to the Indian Ocean will still be nearly zero. You will still feel almost weightless. But as you climb, there will be less and less mass above, and more and more below. The pull toward the core will feel greater and greater, and you will feel less and less weightless, until you are standing on the Earth’s surface, staring at the Hollywood sign, feeling heavy again.
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