Tag Archives: planet

The ten year watch

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In the early hours of 1 March 2002, the largest Earth observation satellite ever built soared into orbit from ESA’s launch base in Kourou, French Guiana. For a decade, Envisat has been keeping watch over our planet.

The eight-tonne satellite has doubled its planned five-year lifetime, circling Earth more than 50 000 times. With ten sophisticated optical and radar sensors, the satellite is continuously observing and monitoring Earth’s land, atmosphere, oceans and ice caps. An estimated 2000 scientific publications have been based on this information. … (ESA)

The Hayabusa Booty

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The first dust grains ever retrieved from the surface of an asteroid now confirm that these minor planets are constantly shaped by a continuous barrage of high-speed microscopic impacts, scientists find.

The Japanese asteroid probe Hayabusasucceeded in returning more than 1,500 grains of dustfrom the asteroid 25143 Itokawa when it parachuted into the Australian outback in June 2010. Already, the samples from this 1,800 foot-long (550 meter) rubble pile have helped solve the longstanding mystery of where most meteorites striking our planet come from. … (SPACE.com)

Heavy!!

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A newly discovered planet 4,000 light-years away is just too dense.

Dubbed CoRoT-20b, the planet is thought to be a gas giant about four-fifths the size of Jupiter and orbits close to a sunlike star.

Despite the new planet’s relatively diminutive size, this world has four times Jupiter’s mass, making CoRoT-20b one of the densest known planets, a new study says.

That poses a problem for astronomers: If CoRoT-20b is structured like a traditional gas giant, with a solid core surrounded by a gassy atmosphere, the planet’s core would have to make up 50 to 77 percent of the world’s total mass.

By contrast, Jupiter’s core is thought to represent just 15 percent of that planet’s mass.

To have such a robust core, CoRoT-20b would defy current theories for how planets form. … (NGC)

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)