Hiển thị các bài đăng có nhãn planet. Hiển thị tất cả bài đăng
Hiển thị các bài đăng có nhãn planet. Hiển thị tất cả bài đăng

Thứ Năm, 23 tháng 2, 2012

'Waterworld': The strange planet covered in a 'big, hot ocean'

Astronomers discover a bizarre new planet that may be home to exotic substances like "hot ice" and "superfluid water" Maybe it's time for snorkel-equipped spacesuits. NASA scientists have just confirmed an entirely new category of planet just 40 light years away: A "strangely unique" world with a diameter 2.7 times larger than Earth that's covered almost entirely in water. Here, a guide to GJ 1214b, a one-of-a-kind "waterworld":

Why is this planet apparently unique?
Its surface is shrouded in thick, wet fog. In our solar system, planets fit into one of three categories: "Rocky and terrestrial like Mars and Earth, gas giants such as Jupiter and Saturn, and ice giants like Uranus and Neptune," says Fox News. But this new planet doesn't fit neatly into any of these boxes. "GJ 1214b is like no planet we know of," says astronomer Zachory Berta. "A huge fraction of its mass is made up of water."

SEE MORE: Is Mars too dry for life?

How much water does this planet have?
Much more than Earth. The findings, published in the Astrophysical Journal, suggest that as much as 50 percent of the exoplanet's mass is water. Its surface temperature is also unusually warm at 450 degrees, says Phil Plait at Discover, or "hot enough to roast a chicken." As Harvard University astronomer David Charbonneau explains: "If you want to describe in one sentence what this planet is, it's a big, hot ocean." Its atmosphere is approximately 10 times thicker than Earth's, creating enormous pressure that together with the intense heat, says Berta, "would form exotic materials like 'hot ice' or 'superfluid water' — substances that are completely alien to our everyday experiences."

Could this "waterworld" host life?
Not human life. And if GJ 1214b can support life, those organisms would be very strange. "This planet will occupy us for years," said Charbonneau. "That's part of what's so exciting about it."

SEE MORE: The 'strongest solar storm since 2005': A guide

How did astronomers find it?
The planet's location was actually pinpointed in December 2009, when its orbit crossed that of a nearby red dwarf star. At the time, scientists noticed something peculiar about GJ 1214b's glow. When a planet passes in front of a star, its atmosphere typically absorbs some of the star's light (just like Earth's atmosphere absorbs light from the sun). Based on the resulting color, scientists can speculate on the composition of the planet's atmosphere. "Water vapor, for example, has a different impact on a spectrum taken of the star's light, than, say, carbon dioxide," says Phil Plait at Discover. 

Sources: BBC News, Discover, Fox News, Mother Nature Network, Toronto Standard

SEE MORE: A massive solar storm's 'spectacular' aurora borealis 

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Thứ Hai, 6 tháng 2, 2012

Why we'll never find another planet like Earth

It doesn't matter how hard NASA looks, says Mark Fischetti at Scientific American. Until it identifies another planet with plants, Earth remains stubbornly unique

Every few days, it seems, NASA discovers a new exoplanet that could "potentially" be the next Earth. But the truth is, we'll never find another planet quite like ours, argues Mark Fischetti at Scientific American. While experts are hunting for a hospitable Earth 2.0 that boasts liquid water and human-friendly temperatures, they're ignoring one factor that gives our blue planet its inimitable properties: Plants. Far from being a mere byproduct of Earth's water and soil, our trees and flora helped shape the planet's entire surface. Green life "soaked up all the carbon dioxide from the atmosphere" over 450 million years ago, lowering temperatures enough to let other organisms thrive. And the roots of forests shaped our planet's riverbeds, allowing vegetation to grow while softening the soil for agriculture. Here, Fischetti explains why Earth is truly one of a kind: 

Before the era of plants, water ran over Earth's landmasses in broad sheets, with no defined courses. Only when enough vegetation grew to break down rock into minerals and mud, and then hold that mud in place, did river banks form and begin to channel the water. The channeling led to periodic flooding that deposited sediment over broad areas, building up rich soil. The soil allowed trees to take root. Their woody debris fell into the rivers, creating logjams that rapidly created new channels and caused even more flooding, setting up a feedback loop that eventually supported forests and fertile plains. ...

Even if plants do sprout [on another planet], they will evolve differently, crafting a different surface on the orb they call home.

Read entire article at Scientific American.

SEE MORE: 2011's top mysteries of space

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