Tag Archives: sun

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)

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)

IBEX vacuum cleaning

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A particle-gobbling probe has snared some alien travelers: tiny particles from interstellar space that, after being born from the ashes of an exploding star, breached a protective bubble blown by the sun and sailed into the jaws of the awaiting spacecraft.

“These are some first observations of interstellar material, really alien matter,” Dave McComas, a principal investigator for NASA’s Interstellar Boundary Explorer spacecraft, or IBEX, said January 31 in a NASA press conference announcing the findings. “This alien interstellar material is really the stuff that stars and planets and people — all of us — are made of,” said McComas, of the Southwest Research Institute in San Antonio. …(ScienceNews)

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Kepler sleuthing on

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NASA’s Kepler mission has discovered 11 new planetary systems hosting 26 confirmed planets. These discoveries nearly double the number of verified planets and triple the number of stars known to have more than one planet that transits, or passes in front of, the star. Such systems will help astronomers better understand how planets form.

The planets orbit close to their host stars and range in size from 1.5 times the radius of Earth to larger than Jupiter. Fifteen are between Earth and Neptune in size. Further observations will be required to determine which are rocky like Earth and which have thick gaseous atmospheres like Neptune. The planets orbit their host star once every six to 143 days. All are closer to their host star than Venus is to our sun. … (NASA)

Ice fiesta on Vesta?

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Though generally thought to be quite dry, roughly half of the giant asteroid Vesta is expected to be so cold and to receive so little sunlight that water ice could have survived there for billions of years, according to the first published models of Vesta’s average global temperatures and illumination by the sun.

“Near the north and south poles, the conditions appear to be favorable for water ice to exist beneath the surface,” says Timothy Stubbs of NASA’s Goddard Space Flight Center in Greenbelt, Md., and the University of Maryland, Baltimore County. Stubbs and Yongli Wang of the Goddard Planetary Heliophysics Institute at the University of Maryland published the models in the January 2012 issue of the journal Icarus. The models are based on information from telescopes including NASA’s Hubble Space Telescope. …(NASA)

Clean Up Earth’s Orbital Ghetto

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Space debris includes discarded man-made objects such as defunct satellites, which have exceeded their life times or malfunctioned, and rockets that have finished their missions.
Space debris is inevitably created during satellite operations. For example, solar array paddles are folded and tied with wires for launch, and when the paddles were deployed, the wire was discarded into space. Camera lens caps were also thrown away in space.
A vast number of fragments are created from either explosions or collisions. Most space debris is a result of the break-ups caused by these events. Satellites are launched on rockets that carry extra amounts of fuel. After a rocket has injected its satellite into the orbit, its remaining fuel can trigger an explosion, if its fuel tanks are heated by sunlight and highly pressurized. Satellites also carry fuel so they can keep the right orbit and attitude, so explosions can also happen if the fuel tanks of post-mission satellites get heated enough by sunlight. There have been about 200 such explosions confirmed to date.
And today there are also more collisions, as Earth’s orbit gets more crowded. The collision probability is becoming higher and higher. …. (JAXA)