It may look like something from “The Lord of the Rings,” but this fiery swirl is actually a planetary nebula known as ESO 456-67. Set against a backdrop of bright stars, the rust-colored object lies in the constellation of Sagittarius (The Archer), in the southern sky.
Despite the name, these ethereal objects have nothing at all to do with planets; this misnomer came about over a century ago, when the first astronomers to observe them only had small, poor-quality telescopes. Through these, the nebulae looked small, compact, and planet-like — and so were labeled as such.
When a star like the sun approaches the end of its life, it flings material out into space. Planetary nebulae are the intricate, glowing shells of dust and gas pushed outwards from such a star. At their centers lie the remnants of the original stars themselves — small, dense white dwarf stars.
In this image of ESO 456-67, it is possible to see the various layers of material expelled by the central star. Each appears in a different hue — red, orange, yellow, and green-tinted bands of gas are visible, with clear patches of space at the heart of the nebula. It is not fully understood how planetary nebulae form such a wide variety of shapes and structures; some appear to be spherical, some elliptical, others shoot material in waves from their polar regions, some look like hourglasses or figures of eight, and others resemble large, messy stellar explosions — to name but a few.
The small near-Earth asteroid 2012 DA14 passed safely by Earth on Feb. 15, 2013. Its closest approach, about 17, 150 miles above the Indian Ocean, came at about 11:25 a.m. PST (2:55 p.m. EST and 1925 UTC). NASA’s Near-Earth Object Program Office accurately predicted the asteroid’s path and that there was no chance it might collide with Earth. The flyby did provide scientists and astronomers a unique opportunity to study a near-Earth object up close.
Astronomers say they have uncovered evidence for what could be four super-Earth planets orbiting within the habitable zones of two stars within 22 light-years of Earth.
Three of those candidate planets are among a tightly packed clutch of five that orbit Gliese 667C, part of a triple-star system 22 light-years away in the constellation Scorpius. The other possible planet is one of five orbiting tau Ceti, a sun-like star 12 light-years away in the constellation Cetus.
Taken together, the detections not only add to accumulating evidence that planets look to be more common than stars - and that planets in habitable zones could be more common than previously thought, some of researchers reporting the finds say.
The finds also illustrate the power of improved statistical tools to boldly uncover candidate planets where no planet had been found before.
The evidence for these candidate planets requires independent confirmation, the researchers caution. Still, the tools represent “a real breakthrough,” says Steven Vogt, an astronomer at the University of California at Santa Cruz and a member of the team reporting the results for tau Ceti. The approach the team took leaves only about one chance in 3 million that the detections could herald something other than a planet.
The stereotypical black hole is a region of space that powerfully sucks in anything that comes near. While that’s sort-of true, many black holes are surrounded by quasars: dense, matter-rich regions at the centers of galaxies that eject astonishing volumes of radio waves, light and many other forms of energy.
Astronomers, using data from the European Southern Observatory’s Very Large Telescope in Chile, have spotted a quasar (labelled SDSS J1106+1939) that is spewing more energy than any one found previously. “The rate that energy is carried away by this huge mass of material ejected at high speed from SDSS J1106+1939 is at least equivalent to two million times the power output of the Sun,” said Nahum Arav of Virginia Tech in a statement. “This is about 100 times higher than the total power output of the Milky Way galaxy—it’s a real monster of an outflow.”
Quasars, some of the most luminous and energetic objects in the known universe, result from matter drawn in by the immense gravitational force of the largest type of black holes. While all this gravity easily sucks in visible light, scientists believe much of the matter doesn’t make it all the way in, instead condensing into a swirling accretion disk.
There’s an orphan planet roaming our galactic neighborhood.
It’s a globe of gas about the size of Jupiter, astronomers say. And it’s out there by its lonesome, untethered to any star, drifting about 100 light-years from Earth. (In astronomical terms, that’s close.)
Astronomers have spied lonely planets before. But this newest object, seen near the southern constellation Dorado, is the closest to Earth yet found.
Unobscured by starlight, the new planet — it has no name, just a catalog number — provides a perfect opportunity for astronomers to learn about the mysterious class of “substellar objects.” Such rogue bodies might number in the billions in our galaxy alone.
“There could really be a lot of them,” said Christian Veillet, former director of the Canada-France-Hawaii Telescope, who studied the lonely planet. “But it’s a big challenge in terms of observing them.”
That’s because these drifting bodies are dark. With no home star, they reflect no starlight, nor do they generate any. But, like an iron pulled from a fire, the youngest of these objects still glow with the heat of their creation.
If you really hate living here on Earth the next best place to be is just a hop, skip, and a jump away!
But research to appear in Astronomy and Astrophysics has found three more - among them a “super-Earth” seven times our planet’s mass, in the habitable zone where liquid water can exist.
Many more observations will be needed to confirm any other similarities.
But the find joins an ever-larger catalogue of more than 800 known exoplanets, and it seems only a matter of time before astronomers spot an “Earth 2.0” - a rocky planet with an atmosphere circling a Sun-like star in the habitable zone.
HD 40307, which lies 42 light-years away, is not particularly Sun-like - it is a smaller, cooler version of our star emitting orange light.
But it is subtle variations in this light that permitted researchers working with the Rocky Planets Around Cool Stars (Ropacs) network to find three more planets around it.
Most of the stars that will ever exist have already been born, according to the most comprehensive survey of the age of the night sky.
An international team of astronomers used three telescopes — the UK Infrared Telescope and the Subaru Telescope, both in Hawaii, and Chile’s Very Large Telescope — to study trends in star formation, from the earliest days of the universe. Extrapolating their findings has revealed that half of all the stars that have ever existed were created between 9 and 11 billion years ago, with the other half created in the years since. That means that rate at which new stars are born has dropped off massively, to the extent that (if this trend continues) 95 percent of all the stars that this universe will ever see have already been born.
Several studies have looked at specific time ‘epochs’, but the different methods used by each study has restricted the ability to compare their findings and discern a fuller model of how stars have evolved over the course of the entire universe’s lifespan.
Astronomers have found a star that breaks speed records as it orbits the Milky Way’s central black hole, covering 3,100 miles (5,000 kilometers) per second as it whips around the black hole in less than a dozen years. The discovery offers scientists a unique chance within the decade to test Einstein’s theory of relativity in an extreme environment. The star is named S0-102. It’s one of a class of “S-stars” that surround the center of the sun’s home galaxy in a kind of spherical shell. It has an orbital period of 11.5 years, give or take 3 1/2 months, making it the shortest-period star ever found in the region. The previous record was set by S0-2, which has a 16-year period.
The presence of two short-period stars means astronomers can look at the precession (change in orientation) of their orbits over time and use that information to learn how much space has been curved by the immense gravity of the galaxy’s central black hole, which weighs in at 4 million times the sun’s mass.
Such tests have been done before. The most famous study looked at the movement of the planet Mercury around the sun. Astronomers of the 19th century noticed Mercury’s orbit was precessing more than could be accounted for by Newton’s theory of gravity. At first they proposed the presence of another planet inside Mercury’s orbit, but in the early 20th century Einstein was able to use his theory of relativity to predict exactly how much “extra” precession should happen as a result of space being curved by the sun’s gravity, forcing the planet into a different path.
More at Ars Technica
New telescopes are allowing us to look at space more accurately than ever - and what they uncover could change our world
The other night I trained my telescope on a few stars that resemble the Sun and are now known to have planets—inconspicuous and previously unheralded stars such as 61 Virginis and 47 Ursae Majoris, each found to be orbited by at least three planets, and HD 81040, home to a gas giant six times as massive as mighty Jupiter.
I could see none of the actual planets—lost in the glare of their stars, exoplanets can only rarely be discerned through even the largest telescopes—but just knowing they were there enhanced the experience. Watching those yellow stars dancing in the eyepiece, I found myself grinning widely in the dark, like an interstellar Peeping Tom.
When I was a boy, the prospect of finding exoplanets was as dim and distant as the planets themselves. Theorists had their theories, but nobody knew whether planets were commonplace or cosmically rare. My 1959 edition of the opulent Larousse Encyclopedia of Astronomy noted that no planets of other stars had yet been identified, but predicted that “future instrumental and technical improvements may confidently be expected to reveal many things that are now hidden.”
And so they did. Thanks to space telescopes, digital cameras, high-speed computers and other innovations scarcely dreamt of a half century ago, astronomers today have located hundreds of exoplanets. Thousands more are awaiting confirmation. New worlds are being discovered on an almost daily basis.
These revelations advance the quest to find extraterrestrial life, help scientists better understand how our solar system evolved and provide a more accurate picture of how the universe—which is to say, the system that created us—actually works.
The Moon is typically seen bathed in the white light of the sun. Like Earth viewed from above, in its full state it looks like a perfect sphere, as smooth as a snooker ball. In fact, as scientists from Arizona State University in Tempe have just revealed in a high-resolution Moon map, it has a topography that is as varied and in places extreme as anything on our planet.
In the course of its monthly elliptical orbit, the Moon moves around Earth at an average distance of roughly a quarter of a million miles. Space is a harsh environment, and the Moon has virtually no atmosphere, extremes of temperature (from -233°C at night to +123°C in the day), and no human presence—which makes mapping it tricky.
To do it, the multinational team behind this image first designed a new Wide Angled Camera (WAC) capable of withstanding the vicissitudes of outer space. They then hitched a lift for it on a spacecraft: the Lunar Reconnaissance Orbiter (LRO), which was launched by NASA in 2009 and has already gone beyond its initial mission to spend a year in close orbit of the Moon. The palm-sized WAC was mounted on the LRO, which flies at an average altitude of 50km (30 miles) above the Moon’s surface. Each picture it takes covers a swathe 70km wide.
As the LRO is constantly circumnavigating the Moon, with each orbit 30km (in ground distance) from the last, the pictures it takes overlap, giving a stereo view of almost every patch of lunar ground, every month. About 69,000 of these images were sent back and fed into a computer, which used them to build an accurate model of almost all the terrain. The bits at extreme latitudes that the WAC couldn’t survey—the holes at the poles—were covered by another laser instrument on board, known as LOLA (Lunar Orbiter Laser Altimeter).
But it was only when the models were shaded, to give a sense of the relief, and coloured in with different altitudes shown by different colours, that the topography was transformed into a living landscape—of craters, mountains and the vast basalt plains that early astronomers mistook for seas and lakes. “I could not be more pleased with the quality of the map,” said Mark Robinson, who heads the Arizona team. “It’s phenomenal. The richness of detail should inspire lunar geologists around the world for years to come.”