Tag Archives: planet

Steamy windows for possible settlers

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This looks like a mighty cool – hot – planet. A waterworld under an atmosphere of water vapor. There could be boiling some life over there! It’s clear (yet damp) that there’s a whole lot more to (exo)planets than the casual rock- and gas planets we have in our neighborhood:

Observations by the NASA/ESA Hubble Space Telescope have come up with a new class of planet, a waterworld enshrouded by a thick, steamy atmosphere. It’s smaller than Uranus but larger than Earth.

An international team of astronomers led by Zachory Berta of the Harvard-Smithsonian Center for Astrophysics (CfA) made the observations of the planet GJ 1214b.

“GJ 1214b is like no planet we know of,” Berta said. “A huge fraction of its mass is made up of water.”

The ground-based MEarth Project, led by CfA’s David Charbonneau, discovered GJ 1214b in 2009. This super-Earth is about 2.7 times Earth’s diameter and weighs almost seven times as much. It orbits a red-dwarf star every 38 hours at a distance of 2 million kilometers, giving it an estimated temperature of 230 degrees Celsius.

In 2010, CfA scientist Jacob Bean and colleagues reported that they had measured the atmosphere of GJ 1214b, finding it likely that it was composed mainly of water. However, their observations could also be explained by the presence of a planet-enshrouding haze in GJ 1214b’s atmosphere. … (Hubble)

Tellurium in the distance

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Nearly 13.7 billion years ago, the universe was made of only hydrogen, helium and traces of lithium — byproducts of the Big Bang. Some 300 million years later, the very first stars emerged, creating additional chemical elements throughout the universe. Since then, giant stellar explosions, or supernovas, have given rise to carbon, oxygen, iron and the rest of the 94 naturally occurring elements of the periodic table.

 

Today, stars and planetary bodies bear traces of these elements, having formed from the gas enriched by these supernovas over time. For the past 50 years, scientists have been analyzing stars of various ages, looking to chart the evolution of chemical elements in the universe and to identify the astrophysical phenomena that created them.

 

Now a team of researchers from institutions including MIT has detected the element tellurium for the first time in three ancient stars. The researchers found traces of this brittle, semiconducting alloy — which is very rare on Earth — in stars that are nearly 12 billion years old. The findingsupports the theory that tellurium, along with even heavier elements in the periodic table, likely originated from a very rare type of supernova during a rapid process of nuclear fusion. The researchers published their findings online in Astrophysical Journal Letters. …  (MIT-news)

Dried up aliens

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Alien planets might experience tidal forces powerful enough to remove all their water, leaving behind hot, dry worlds like Venus, researchers said.

 

These findings might significantly affect searches for habitable exoplanets, scientists explained. Although some planets might dwell in regions around their star friendly enough for life as we know it, they could actually be lifelessly dry worlds.

 

The tides that we experience on Earth are caused by the gravitational pull of the moon and sun. Our tides are nothing compared to what we see elsewhere in the solar system — the gravitational pull Europa experiences from Jupiter leads to tidal forces roughly 1,000 times stronger than what Earth feels from our moon, flexing and heating Europa. … (Discovery)

Venus on the brakes

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ESA’s Venus Express spacecraft has discovered that our cloud-covered neighbour spins a little slower than previously measured. Peering through the dense atmosphere in the infrared, the orbiter found surface features were not quite where they should be.

Using the VIRTIS instrument at infrared wavelengths to penetrate the thick cloud cover, scientists studied surface features and discovered that some were displaced by up to 20 km from where they should be given the accepted rotation rate as measured by NASA’s Magellan orbiter in the early 1990s. These detailed measurements from orbit are helping scientists determine whether Venus has a solid or liquid core, which will help our understanding of the planet’s creation and how it evolved.  … (ESA)

 

Super. Massive. Impressive.

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This image from NASA’s Chandra X-ray Observatory shows the center of our Galaxy, with a supermassive black hole known as Sagittarius A* (Sgr A* for short) in the center. Using intermittent observations over several years, Chandra has detected X-ray flares about once a day from Sgr A*. The flares have also been seen in infrared data from ESO’s Very Large Telescope in Chile.

A new study provides a possible explanation for the mysterious flares. The suggestion is that there is a cloud around Sgr A* containing hundreds of trillions of asteroids and comets , which have been stripped from their parent stars. The panel on the left is an image containing nearly a million seconds of Chandra observing of the region around the black hole, with red representing low-energy X-rays, green as medium-energy X-rays, and blue being the highest.

An asteroid that undergoes a close encounter with another object, such as a star or planet, can be thrown into an orbit headed towards Sgr A*, as seen in a series of artist’s illustrations beginning with the top-right panel. If the asteroid passes within about 100 million miles of the black hole, roughly the distance between the Earth and the Sun, it would be torn into pieces by the tidal forces from the black hole (middle-right panel).

These fragments would then be vaporized by friction as they pass through the hot, thin gas flowing onto Sgr A*, similar to a meteor heating up and glowing as it falls through Earth’s atmosphere. A flare is produced (bottom-right panel) and eventually the remains of the asteroid are swallowed by the black hole.  … (Chandra)

Clean. Very clean.

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Mars may have been arid for more than 600 million years, making it too hostile for any life to survive on the planet’s surface, according to researchers who have been carrying out the painstaking task of analysing individual particles of Martian soil. Dr Tom Pike, from Imperial College London, will discuss the team’s analysis at a European Space Agency (ESA) meeting on 7 February 2012. The researchers have spent three years analysing data on Martian soil that was collected during the 2008 NASA Phoenix mission to Mars. Phoenix touched down in the northern arctic region of the planet to search for signs that it was habitable and to analyse ice and soil on the surface.

The results of the soil analysis at the Phoenix site suggest the surface of Mars has been arid for hundreds of millions of years, despite the presence of ice and the fact that previous research has shown that Mars may have had a warmer and wetter period in its earlier history more than three billion years ago. The team also estimated that the soil on Mars had been exposed to liquid water for at most 5,000 years since its formation billions of years ago. They also found that Martian and Moon soil is being formed under the same extremely dry conditions. …(SpaceRef)

New superearth, new superchances

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A potentially habitable alien planet — one that scientists say is the best candidate yet to harbor water, and possibly even life, on its surface — has been found around a nearby star.

The planet is located in the habitable zone of its host star, which is a narrow circumstellar region where temperatures are neither too hot nor too cold for liquid water to exist on the planet’s surface.

“It’s the Holy Grail of exoplanet research to find a planet around a star orbiting at the right distance so it’s not too close where it would lose all its water and boil away, and not too far where it would all freeze,” Steven Vogt, an astronomer at the University of California, Santa Cruz, told SPACE.com. “It’s right smack in the habitable zone — there’s no question or discussion about it. It’s not on the edge, it’s right in there.” … (SciAm)