Tampilkan postingan dengan label Astronomi. Tampilkan semua postingan
Tampilkan postingan dengan label Astronomi. Tampilkan semua postingan
Rabu, 05 Juni 2013
Tangga "Hantu" di Cincin Saturnus
Foto tangga "hantu" ini berhasil diambil Cassini dari jarak 686 ribu kilometer dari Saturnus dengan sudut fase sekitar 162 derajat.
Fenomena berbentuk tangga "hantu" di cincin F Saturnus, diambil pada 13 Februari 2013 dan baru ditampilkan di situs milik NASA pada 27 Mei 2013 lalu. (Cassini/NASA)
Cincin F selaku salah satu cincin yang mengelilingi Saturnus dikenal memiliki struktur yang misterius. Cincin yang mengorbit sekitar 82.000 kilometer dari titik ekuatorial tertinggi ini adalah struktur yang lekat dan sabuk berseluk dari partikel es cerah.
Lebarnya bisa mencapai 30 hingga 500 kilometer. Terkadang bisa nampak seperti selukan yang solid atau kabel terbelit yang dikelilingi oleh kabut tebal.
Rabu, 12 Desember 2012
Maya Calendars Actually Predict That Life Goes On
Doomsday? No way. Ancient Maya said we’ll be around another 7,000 years or so.
This December, not everyone is concerned with making plans for the New Year—especially not the people who think doomsday will get here first. Instead of planning parties, they're stockpiling food, refining escape routes, and honing survival skills ahead of the alleged date on which the Maya calendar "ends"—December 21, 2012.
So should we all be preparing for imminent apocalypse? According to the scholars, no.
The ancient Maya are usually cited as the predictors of the world coming to an end this month: One of their "great cycles" supposedly ends now. But the Maya were brilliant mathematicians and fantastic record keepers. They didn't have just one calendar. They developed many different kinds, including a cyclical solar calendar and a sacred almanac. They also measured time with something known as the Long Count, which were great cycles of 5,000 years.
Sabtu, 31 Desember 2011
Badai Matahari
Magnet Matahari
Matahari yang menyinari bumi selalu beraktivitas atau bergerak. Selama pergerakannya normal, matahari gak berbahaya. Tapi kegiatan matahari gak selalu sama, kadang berubah-ubah. Berdasarkan penelitian, setiap 11 tahun terjadi aktivitas besar matahari. Salah satunya keluar badai berupa semburan proton & elektron dari matahari. Diperkirakan tahun 2011 & 2012 sekarang ini terjadi puncak semburan badai matahari. Inilah salah 1 gosip akan terjadi kiamat pada tahun 2012 seperti di film 2012
Sabtu, 30 Juli 2011
"Spectacular" Double Meteor Shower Peaks Tonight
Photograph by Siddhartha Saha, Your Shot
A celestial traffic jam may be on tap tonight as two meteor showers combine forces to put on a brilliant sky show.
One of the best shooting star events of the year is the annual August Perseid meteor shower. However this year's Perseids peak, on August 12, happens to coincide with a bright full moon—drastically cutting down the number of meteors visible to the naked eye. Yet while the main event might be blocked out by the blinding moonlight, the opening act promises to be much better.
This year the lesser known Delta Aquarid meteor shower is expected to peak on Friday night, when the Delta Aquarids' more productive Perseid cousin is just starting to ramp up.
Together the showers will produce anywhere between 15 and 30 shooting stars per hour under clear, dark skies. "While the moon is set to be an unpleasant guest for the Perseid peak, skywatchers are not out of luck as the Delta Aquarids could be one of the best meteor showers of the year," said Raminder Singh Samra, astronomer at the H.R. MacMillan Space Centre in Vancouver, Canada.
"The new moon during the peak of the Delta Aquarids may actually allow for a much more spectacular display."
Trojan Asteroid Found Sharing Earth's Orbit—A First
Illustration courtesy Paul Wiegert, University of Western Ontario
A tiny space rock that's partially tethered to Earth by a gravitational leash is our planet's first known Trojan asteroid, astronomers say.
Trojan asteroids have been found around Jupiter, Neptune, and Mars, and Saturn is orbited by a few groups of Trojan moons. Earth's newfound Trojan is about 1,000 feet (300 meters) wide and sits about 50 million miles (80 million kilometers) in front of Earth.
"It is in orbit around the sun in the same path that our orbital path is, and it is controlled partly by our gravity, but the sun's gravity controls it more," said Martin Connors, an astronomer at Athabasca University in Canada and one of the co-discoverers of the object.
Kamis, 28 Juli 2011
Black Hole Hosts Universe's Most Massive Water Cloud
Illustration courtesy ESA/NASA
In a galaxy 12 billion light-years away resides the most distant and most massive cloud of water yet seen in the universe, astronomers say.
Weighing in at 40 billion times the mass of Earth, the giant cloud of mist swaddles a type of actively feeding supermassive black hole known as a quasar.
Among the brightest and most energetic objects in the universe, quasars are black holes at the centers of galaxies that are gravitationally consuming surrounding disks of material while burping back out powerful energy jets.
"Soccer Ball" Nebula Discovered by Amateur Astronomer
Image courtesy Gemini Observatory/AURA
A dying star's wheezing cough has puffed out a gas shell reminiscent of a big blue soccer ball, scientists say.
The discovery could shed new light on the shaping of planetary nebulae—so called because 18th-century astronomers using early telescopes mistook the stellar clouds for gas-giant planets.
Amateur astronomer Matthias Kronberger discovered the soccer-ball nebula, called Kronberger 61, in January 2011 after poring over digitized photos of sky surveys from the 1980s. After he alerted professional astronomers, the Gemini Observatory in Hawaii zoomed in on the region to create the new, color-composite image.
Kronberger 61 lies roughly 13,000 light-years away in the Cygnus constellation and is almost perfectly round—an oddity when compared with the other 3,000 or so planetary nebulae already discovered.
Kamis, 14 Juli 2011
Earth Has "Spare Tire"—And Ice Melt's Keeping It That Way
Photograph courtesy NASA
Earth isn't losing its "spare tire" as fast as it should be, according to new research—and it's definitely not because the planet's not getting enough water.
In fact, melting ice from Antarctica and Greenland (map) is giving the oceans huge infusions of water, which then gets pulled toward the Equator—counteracting a millennia-old slimming trend around the planet's middle, experts say.
Researchers have long known that Earth isn't a perfect sphere. Rotational forces cause the planet to bulge at its waistline. A person standing at the North Pole, for example, is about 13 miles (21 kilometers) closer to the center of Earth than someone at the Equator.
That difference has been shrinking, at least over the long term. Ever since scientists have been measuring the equatorial bulge, it's been retracting at a rate of seven millimeters (about a quarter of an inch) a decade—part of a long rebounding from the Ice Age, which lasted from about 2.6 million to 11,700 years ago.
During the Ice Age, "all that ice is sitting there, and it's sitting there for tens of thousands of years," study co-author John Wahr said. At the Poles, "it pushes down on the Earth, and the Earth sinks down underneath it."
The extra Ice Age weight even squished Earth's malleable mantle outward, further enlarging the planet's bulge.
Once the Ice Age ice melted, though, the Poles began to slowly spring back, and they've been doing so ever since.
But now "there's something else going on that offsets [the bulge's shrinkage]," said Wahr, a geophysicist at the University of Colorado.
Space Pictures This Week: Shuttle, Strange Clouds, More
Backlighted by sunshine streaming over Earth's horizon, the European Space Agency's Johannes Kepler automated transfer vehicle separates from the International Space Station on June 20. Stuffed with garbage—including astronaut urine—the unmanned craft tumbled back to Earth the next day, becoming a fireball over a remote section of the Pacific Ocean.
Strange Skies
The electric blue clouds are showing up at ever more southerly latitudes, and astronomers aren't sure why, according to NASA. Their beauty, however, is no mystery, and Northern Hemisphere sky-watchers are advised to scan the heavens for night-shiners between mid-May and late August, when the phenomenon is most common.
Arc of an Eclipse
Because the moon passed almost directly through the center of Earth's shadow, the event was the longest and deepest total lunar eclipse in more than a decade, according to Ben Burress, staff astronomer at the Chabot Space & Science Center in Oakland, California.
Kamis, 16 Juni 2011
Glowing Green Ring Nebula
In a new infrared picture from NASA’s Spitzer Space Telescope, a nebula known as RCW 120 makes a brilliant green “O” against a starry patch of sky.
It may look like a portal to Hell ripped through the fabric of spacetime, but this nebula is actually a bubble of gas and dust that’s formed around an “O” type star, the most massive stellar giants known to exist.
O stars appear blue in visible light and are very hot: Surface temperatures can be higher than 73,340 degrees Fahrenheit (40,727 degrees Celsius).
Because they are so bulky, O stars live fast and die young. Their intense radiation lights up their stellar nurseries shortly after they’re born, and they blow themselves apart as supernovae just a few million years later.
