Earth is the only planet not named after an ancient god.
To celebrate the upcoming release of our new Cassini HD iPad app, I will be posting my favorite images from it all week. These natural color images capture Saturn in all its soft-toned splendor.
Cassini HD will be released in the iTunes store on Saturday, Sept. 15. Take advantage of our special release offer and get it for free that first day only.
1st Alien Planets Found Around Sun-Like Stars in Cluster
For the first time, astronomers have discovered alien planets orbiting sun-like stars located in a crowded star cluster, scientists announced.
Image: Artist’s concept of one of the two gas giant planets discovered around different sun-like stars in the Beehive Cluster, a collection of about 1,000 tightly packed stars located about 550 light-years away from Earth. Credit: NASA/JPL-Caltech
The two newfound worlds are Jupiter-like behemoths far too hot to be habitable. But their existence may hearten those searching for life beyond Earth by helping to show that planets can form in a wide range of environments, such as dense clusters, researchers said.
“We are detecting more and more planets that can thrive in diverse and extreme environments like these nearby clusters,” Mario Perez, NASA astrophysics program scientist in the Origins of Solar Systems Program, said in a statement. “Our galaxy contains more than 1,000 of these open clusters, which potentially can present the physical conditions for harboring many more of these giant planets.”
Tiniest Alien Solar System Discovered: 5 Packed Planets
The most crowded alien planetary system found yet possesses five worlds all orbiting a star at least 12 times closer than Earth does the sun, researchers say.
Image: Kepler observatory spots five planets in close formation around KOI-500, 1,100 light-years from Earth Credit: Illustration by Karl Tate, SPACE.com
Investigators discovered these exoplanets using NASA’s pioneering Kepler space observatory. The orbiting telescope has detected more than 2,300 potential alien worlds since its March 2009 launch. It searches for these planets by observing more than 160,000 stars simultaneously, looking for small dips in stars’ brightness due to orbiting worlds passing in front of them.
The researchers used Kepler to analyze the planetary system around the star KOI-500, a star about the mass of the sun but only about three-quarters its diameter and only about 1 billion years old, less than one-quarter the sun’s age. KOI-500 is approximately 1,100 light-years away in the constellation Lyra, the harp.
Alien Planets Circling Pulsing Stars May Leave Electric Trails
Alien worlds that orbit the energetic dead stars known as pulsars may leave electric currents behind them – anomalies that could help researchers find more of these strange planets.
Image: This artist’s impression shows the planetary system around pulsar PSR B1257+12, one of two pulsars known to be host to at least one planet. Such planets around pulsars may have powerful electromagnetic wakes around them. Credit: NASA/JPL-Caltech/R. Hurt (SSC)
Astronomers know of only four “pulsar planets” so far, and much remains unknown about such worlds, but scientists propose that they formed in the chaos after the supernova explosions that gave birth to the pulsars.
A pulsar is a kind of neutron star, a stellar corpse left over from a supernova, a giant star explosion that crushes protons with electrons to form neutrons. Neutron star matter is the densest known material: A sugar cube-size piece weighs as much as a mountain, about 100 million tons. The mass of a single neutron star surpasses that of the sun while fitting into a ball smaller in diameter than the city of London.
Pulsars spin extraordinarily rapidly, up to thousands of revolutions per second, and they flash like lighthouse beacons — hence their name, which is short for “pulsating star.” They are also extremely magnetic — a kind of pulsar known as a magnetaris the most powerful magnet in the universe.
Despite the exotic nature of pulsars, they have been seen hosting planetary systems.
This image covers Luki Crater in the Southern highlands. This crater formed on the floor of Uzboi Vallis between Hale and Holden craters, near the confluence with Nanedi Vallis.
Planets Can Form in the Galactic Center
At first glance, the center of the Milky Way seems like a very inhospitable place to try to form a planet. Stars crowd each other as they whiz through space like cars on a rush-hour freeway.
Supernova explosions blast out shock waves and bathe the region in intense radiation. Powerful gravitational forces from a supermassive black hole twist and warp the fabric of space itself.
Yet new research by astronomers at the Harvard-Smithsonian Center for Astrophysics shows that planets still can form in this cosmic maelstrom. For proof, they point to the recent discovery of a cloud of hydrogen and helium plunging toward the galactic center. They argue that this cloud represents the shredded remains of a planet-forming disk orbiting an unseen star.
“This unfortunate star got tossed toward the central black hole. Now it’s on the ride of its life, and while it will survive the encounter, its protoplanetary disk won’t be so lucky,” said lead author Ruth Murray-Clay of the CfA. The results are appearing in the journal Nature.
Pluto is as big as Russia.
(Source: rollin-doobies-up)
How to Build a Planet: Heavy Metals Are Key Ingredients
Image: An artist conception of a newly formed star surrounded by a swirling protoplanetary disk of dust and gas, where debris coalesces to create rocky ‘planetesimals’ that collide and grow to eventually form planets. A new study suggests small rocky planet may actually be widespread in our Milky Way galaxy. Credit: University of Copenhagen, Lars A. Buchhave
Planets may not be able to form without a heaping helping of heavy elements such as silicon, titanium and magnesium, a new study suggests.
Stars that host planets have higher concentrations of such “metals” — astronomer-speak for elements heavier than hydrogen and helium — compared to iron than do planetless stars, the study found.
“To form planets, one needs heavy elements,” said lead author Vardan Adibekyan, of the Centre for Astrophysics of the University of Porto in Portugal.
Connected at birth
Planets coalesce from the disk of dust and gas left over after the birth of their parent star. According to the leading theory of planet formation, the core accretion model, small particles clump together, growing larger and larger until they produce protoplanets.
Scientists have long suspected that stars with higher metallicities are more likely to have planets orbiting them. Iron has long been a primary indicator.
“Usually, in stellar physics, people use the iron content as a proxy of overall metallicity,”
Giant Dying Star Caught Devouring Alien Planet
Image: This artist’s impression shows a red giant engulfing a Jupiter-like planet as it expands. Credit: NASA
A swollen star near the end if its life has been caught devouring one of its own planets — a scenario that could one day be replayed on Earth when our own sun dies in billions of years, scientists say.
Astronomers discovered the cosmic crime scene while studying an ancient star that has expanded in its old age to became a so-called “red giant.” The star, called BD+48 740, is older than our sun and much bigger. Its radius is 11 times larger than that of our sun.
As the star swelled into a red giant, it likely absorbed its innermost planet, researchers said.
“A similar fate may await the inner planets in our solar system, when the sun becomes a red giant and expands all the way out to Earth’s orbit some five billion years from now,” study team member Alex Wolszczan, an astronomer at Pennsylvania State University, said in a statement. The Earth orbits the sun at a distance of about 93 million miles (150 million kilometers).
Two key pieces of evidence identified the star as a planet-killer, researchers said.
First, the astronomers found abnormally high amounts of lithium, a rare element in the universe, inside the star. That fact alone hinted that a missing planet may be involved.
“In the case of BD+48 740, it is probable that the lithium production was triggered by a mass the size of a planet that spiraled into the star and heated it up while the star was digesting it,” said Wolszczan, who led the team that discovered the first planets beyond our solar system, back in 1992.
Then there was the strange orbit of a giant planet discovered around the star. The huge planet is about 1.6 times as massive as Jupiter and circles the star in an extremely elliptical orbit.
“We discovered that this planet revolves around the star in an orbit that is only slightly wider than that of Mars at its narrowest point, but is much more extended at its farthest point,” said study team member Andrzej Niedzielski of Nicolaus Copernicus University in Torun, Poland. “Such orbits are uncommon in planetary systems around evolved stars and, in fact, the BD+48 740 planet’s orbit is the most elliptical one detected so far.”
Spectacular false color images of Mercury from NASA’s Messenger mission. Click on the top image to see the full version.
A Star With Nine Planets, Maybe More?
Exactly how many planets orbit any given star is still a major unknown in exoplanetary science. The two primary techniques for detecting planets and quantifying their characteristics have significant limitations that blinker us to the full contents of other solar systems. Radial velocity measurements pick up the tell-tale motion of a star around a system’s common center-of-mass, or balance point, due to the gravitational pull of any planets. But the smaller the planets and the further they are from the star the weaker the signal. Multiple planets and longer orbital periods confound the situation by producing complex patterns that may also be incompletely sampled in data that spans only a few years. Transit observations, such as those undertaken by the Kepler mission, are biased towards the detection of large planets in small orbits around small stars where it is most likely for a planet to block the light from the star more frequently.
All of this means that in essentially all currently known systems we may have only incomplete information about the true number of orbiting planets. Nonetheless, stars with multiple planet detections certainly crop up. Of the over 550 confirmed exoplanetary systems there are over 90 with more than one planet (a total of more than 760 worlds). Now a new study of radial velocity data from the HARPS instrument suggests that one of these systems, HD 10180, may harbor ninemajor planets – usurping our own solar system from the top of the pile of planetary richness.
