The team thinks the planet was destroyed as its ageing star expanded in size
Astronomers have found evidence for a planet being devoured by its star, yielding insights into the fate that will befall Earth in billions of years.
The team uncovered the signature of a planet that had been “eaten” by looking at the chemistry of the host star.
They also think a surviving planet around this star may have been kicked into its unusual orbit by the destruction of a neighbouring world.
Details of the work have been published in Astrophysical Journal Letters.
New data suggest the confirmation of the exoplanet Gliese 581g and the best candidate so far of a potential habitable exoplanet. The nearby star Gliese 581 is well known for having four planets with the outermost planet, Gliese 581d, already suspected habitable. This will be the first time evidence for any two potential habitable exoplanets orbiting the same star. Gliese 581g will be included, together with Gliese 667Cc, Kepler-22b, HD85512, and Gliese 581d, in the Habitable Exoplanets Catalog of the PHL @ UPR Arecibo as the best five objects of interest for Earth-like exoplanets. http://www.dailygalaxy.com/my_weblog/2012/07/-image-of-the-day-the-kepler-5-nasas-short-list-of-potential-habitable-exoplanets.html#more
Jupiter’s rings revealed as it eclipses the sun, as viewed from Galileo when it orbited from 1995 to 2003
Explanation: Why does Jupiter have rings? Jupiter’s rings were discovered in 1979 by the passing Voyager 1 spacecraft, but their origin was a mystery. Data from the Galileo spacecraft that orbited Jupiter from 1995 to 2003 later confirmed that these rings were created by meteoroid impacts on small nearby moons. As a small meteoroid strikes tiny Adrastea, for example, it will bore into the moon, vaporize, and explode dirt and dust off into a Jovian orbit. Pictured above is an eclipse of the Sun by Jupiter, as viewed from Galileo. Small dust particles high in Jupiter’s atmosphere, as well as the dust particles that compose the rings, can be seen by reflected sunlight.
“16 moons orbit you, and invisible dust-like ring surrounds you… Jupiter!”
Milky Way on collision course with foreign galaxy
Nasa astronomers announce they are able to predict “with certainty” that our Milky Way galaxy is on track to collide with neighbouring Andromeda galaxy.
Video courtesy: Nasa, ESA, M. Estacion, F. Summers, G. Bacon, B. Moster, J. Anderson, R. van der Marel, and S.T. Sohn (STScI)
In England it is known as the “Plough,” in Germany the “Great Cart,” and in Malaysia the “Seven Ploughs.” Since humanity first turned its eyes skyward, the seven northern hemisphere stars that compose the “Big Dipper” have been a welcome and familiar introduction to the heavens.
“I can recall as a kid making an imaginary line from the two stars that make up the right side of the Big Dipper’s bowl and extending it upward to find the North Star,” said Scott Bolton, principal investigator of NASA’s Juno mission to Jupiter from the Southwest Research Institute in San Antonio. “Now, the Big Dipper is helping me make sure the camera aboard Juno is ready to do its job.”
Launched on Aug. 5, 2011, the solar-powered Juno spacecraft is 279 days and 380 million miles (612 million kilometers) into its five-year, 1,905-million-mile (3,065-million-kilometer) journey to Jupiter. Once there, the spacecraft will orbit the planet’s poles 33 times and use its nine instruments to image and probe beneath the gas giant’s obscuring cloud cover to learn more about Jupiter’s origins, structure, atmosphere and magnetosphere, and look for a potential solid planetary core.
One of those instruments, JunoCam, is tasked with taking closeups of the gas giant’s atmosphere. But, with four-and-a-half years to go before photons of light from Jupiter first fill its CCD (charge-coupled device), and a desire to certify the camera in flight, Juno’s mission planners took a page from their childhood and on March 21, aimed their camera at a familiar celestial landmark.
“I don’t know if it’s the first space-based image of the Big Dipper but, as it was taken when we were well beyond Mars orbit, it’s probably from the farthest out,” said Bolton. “But much more important than that is the simple fact that JunoCam, like the rest of this mission, works as advertised and is ready for its day in the sun - around Jupiter.”
The JunoCam test image of the Big Dipper is online at: http://photojournal.jpl.nasa.gov/catalog/PIA15653 .
Billions of potentially habitable planets may exist within our galaxy, the Milky Way, raising new prospects that life could exist near Earth, a study has found.
Hundreds of thousands of stars crowded into the swirling core of our spiral Milky Way galaxy Photo: NASAResearchers discovered that at least 100 of the ”super-Earths” may be on our galactic doorstep, at distances of less than 30 light years, or about 180 trillion miles, from the sun.
Astronomers say the findings were made after conducting a survey of red dwarf stars, which account for about four in five stars in the Milky Way.
They calculate that around 40 per cent of red dwarfs have a rocky planet not much bigger than Earth orbiting the ”habitable zone”, in which liquid surface water can exist.
Scientists say that where there is water, there also could be life although they add that being in the habitable zone is no guarantee that life has evolved on a planet.
Dr Xavier Bonfils, from Grenoble University in France, who led the international team, said: ”Because red dwarfs are so common - there are about 160 billion of them in the Milky Way - this leads us to the astonishing result that there are tens of billions of these planets in our galaxy alone.”
The Hubble Space Telescope’s sharp view was used to look for gravitational arcs and rings (indicated by arrows), which are produced when one galaxy acts as a lens to magnify and distort the appearance of another galaxy behind it. In this case, the foreground galaxies contain actively accreting black holes called quasars. Image credit: NASA, ESA, EPFL (Switzerland)
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The team hopes to build an even bigger catalog of these quasar lenses, and to use these data to better understand the interplay between black hole feeding and star formation in galaxy evolution.
Read the full Hubble release at http://hubblesite.org/newscenter/archive/releases/2012/14.
Jupiter and Venus conjunction dazzles amateur astronomers
Jupiter and Venus last night appeared next to each other in the night sky in a display that delighted amateur astronomers.
The planets are 450 million miles apart in space, but because they are aligned in the same direction from Earth they last night appeared just three degrees apart.
They were visible towards the West just after sunset and before the stars appeared. They will appear bright and relatively close over the next few weeks, and will be most visible in rural areas where there is less light pollution.
Venus is brighter because of its relative closeness to Earth and because it gets more intense sunlight than Jupiter.
After March 14, Jupiter will drop lower until it is eventually invisible after sunset by mid-April.
But in July, early-risers will be treated to a similar spectacle, in the eastern sky at daybreak.
(Source: telegraph.co.uk)
Time Need Not End In The Multiverse
Imaged Above: Ultimate guide to the Multiverse
Gamblers already had enough to think about without factoring the end of time into their calculations. But a year after a group of cosmologists argued that they should, another team says time need not end after all.
It all started with this thought experiment. In a back room in a Las Vegas casino, you are handed a fair coin to flip. You will not be allowed to see the outcome, and the moment the coin lands you will fall into a deep sleep. If the coin lands heads up, the dealer will wake you 1 minute later; tails, in 1 hour. Upon waking, you will have no idea how long you have just slept.
The dealer smiles: would you like to bet on heads or tails? Knowing it’s a fair coin, you assume your odds are 50/50, so you choose tails. But the house has an advantage. The dealer knows you will almost certainly lose, because she is factoring in something you haven’t: that we live in a multiverse.
The idea that our universe is just one of many crops up in a number of physicists’ best theories, including inflation. It posits that different parts of space are always ballooning into separate universes, so that our observable universe is just a tiny island in an exponentially growing multiverse.
In any infinite multiverse, everything that can happen, will happen - an infinite number of times. That has created a major headache for cosmologists, who want to use probabilities to make predictions, such as the strength of the mysterious dark energy that is accelerating the expansion of our own universe. How can we say that anything is more or less probable than anything else?
Vesta Likely Cold and Dark Enough for Ice
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.
Vesta, the second-most massive object in the asteroid belt between Mars and Jupiter, probably does not have any significant permanently shadowed craters where water ice could stay frozen on the surface all the time, not even in the roughly 300-mile-diameter (480-kilometer-diameter) crater near the south pole, the authors note. The asteroid isn’t a good candidate for permanent shadowing because it is tilted on its axis at about 27 degrees, which is even greater than Earth’s tilt of roughly 23 degrees. In contrast, the moon, which does have permanently shadowed craters, is tilted at only about 1.5 degrees. As a result of its large tilt, Vesta has seasons, and every part of the surface is expected to see the sun at some point during Vesta’s year.
The presence or absence of water ice on Vesta tells scientists something about the tiny world’s formation and evolution, its history of bombardment by comets and other objects, and its interaction with the space environment. Because similar processes are common to many other planetary bodies, including the moon, Mercury and other asteroids, learning more about these processes has fundamental implications for our understanding of the solar system as a whole. This kind of water ice is also potentially valuable as a resource for further exploration of the solar system.
