blog-gasy Siansa: April 2014

Monday, April 28, 2014

NASA discovers the sun has an icy neighbor

NASA's Wide-field Infrared Survey Explorer (WISE) and Spitzer Space Telescope have found what appears to be a brown dwarf, or star-like object, that is as cold as the North Pole, just 7.2 light-years away from the sun.

The closest solar system to the sun is Alpha Centauri, about 4 light-years away.

"It is very exciting to discover a new neighbor of our solar system that is so close," Kevin Luhman, an astronomer at Pennsylvania State University's Center for Exoplanets and Habitable Worlds, said in a statement. "And given its extreme temperature, it should tell us a lot about the atmosphere of planets, which often have similarly cold temperatures."

Brown dwarfs begin as collapsing balls of gas, just like any other star, but they do not have enough mass to sustain nuclear fusion. This new brown dwarf — named WISE J085510.83-071442.5 — was found after WISE surveyed the entire sky at least twice using infrared light (NASA says that cooler objects stand out in infrared light because it captures their thermal glow). It is between -54 and 9 degrees Fahrenheit, which is much colder than the other brown dwarfs discovered by WISE and Spitzer, thought to be around room temperature.

"It is remarkable that even after many decades of studying the sky, we still do not have a complete inventory of the sun's nearest neighbors," Michael Werner, Spitzer's project scientist at the Jet Propulsion Lab, said in a statement. "This exciting new result demonstrates the power of exploring the universe using new tools, such as the infrared eyes of WISE and Spitzer." The animation below, courtesy of NASA/JPL-Caltech/Penn State, shows how the brown dwarf was spotted, thanks to its rapid motion across the sky. --Catherine Garcia

NASA discovers the sun has an icy neighbor

Saturday, April 26, 2014

Telescope in Puerto Rico detects strange, rapid bursts of radio waves

The radio telescope at Arecibo Observatory in Puerto Rico detected well-defined signals like distant bursts of radio waves or brilliant explosions lasting but fractions of a second, a phenomenon only seen before at Parkes Observatory in Australia.

The director of the Astronomy Section at Arecibo Observatory, a part of the National Astronomy and Ionosphere Center, Fernando Camilo, confirmed in an interview with Efe on Thursday the discovery made in November 2012 but never announced until this week.

Camilo said the phenomenon has been detected at least seven times through the radio telescope in Australia, but the importance of this one is that for the first time it has been documented at another observatory, which confirms that this is an astronomical reality and cannot be attributed to some peculiarity of a particular instrument.

"The question now is the nature of this phenomenon," the scientist, who for years studied astronomy in the United States, said.

"This could be a powerful burst of radio waves faraway in the universe, a kind of signal never detected before," which appears to come from outside our galaxy.

The phenomenon detected in November 2012 was a burst that lasted 3 thousandths of a second and came from some unknown point, which the scientist said introduces the idea of a new window on space between galaxies, where, he said, "there are no stars nor anything that shines."

Scientists at Parkes Observatory in Australia first detected these signals in 2007 and calculated them to come from thousands of light years beyond our galaxy.

The discovery at Arecibo Observatory was on Nov. 2, 2012, though the analysis of the phenomenon afterwards took several months to complete. EFE

Telescope in Puerto Rico detects strange, rapid bursts of radio waves

Monday, April 07, 2014

Rare Sight: Mars, Earth and Sun Will Align Next Week - Yahoo News

Mars will be exactly opposite the sun in the sky in a rare cosmic alignment set to take place Tuesday (April 8).

Called an opposition, this happens with Mars from Earth's perspective every 778 days, or 2 years, 1 month and 18 days. Think of Earth and Mars as two cars racing on circular tracks. Because Earth is closer to the sun, it travels faster, completing a circuit in 365 days. Mars is farther from the sun and takes longer, 687 days. By the time Mars has completed one circuit, Earth has a lot of catching up to do to get to a point between the Red Planet and the sun.

This is complicated by the fact that the two racetracks are not exact circles. As Johannes Kepler discovered in the 16th century, the planets follow slightly elliptical paths around the sun, sometimes closer to the Sun (perihelion), sometimes farther away (aphelion). [Best Night Sky Events of April 2014: Stargazing Sky Maps (Gallery)]

Some planets, like Venus and Earth, follow paths that are almost perfect circles. Other planets, like Mercury and Mars, follow more elliptical orbits, which are described as being more eccentric, or differing from a circle.

On the day of opposition, Mars, Earth and the sun fall on a straight line. Six days later, both planets will have moved a little along their orbits, but, because of the eccentricity of its orbit, Mars will be slightly closer to Earth than it was before.

If you look at the complete orbits of the four inner planets, you can see how Venus and Earth follow almost perfect circles centered on the sun. The orbits of Mercury and Mars are slightly askew.

If you look closely at Mars' orbit around the 4 o'clock point, you'll see a little tick mark, which indicates Mars' perihelion, the point when it's closest to the sun. If Earth is somewhere in the same quadrant, Mars will be much closer to Earth than it is right now, when it's on the far side of its orbit from perihelion.

This is where we get the idea of "favorable" and "unfavorable" oppositions of Mars. When Earth passes Mars when Mars is close to perihelion, as it did in August 2003, we have a favorable opposition. When Earth passes Mars when it is close to aphelion, as it did in March 2012, we have a very unfavorable opposition. The opposition next week is slightly more favorable than two years ago, and oppositions will gradually get better until July 2018, when Mars will be close to perihelion and we get a very favorable opposition.

But how much difference does this make? In March 2012, Mars was 62.7 million miles (100.9 million kilometers) from Earth. On April 14, it will be 57.4 million miles (92.4 million km) away. But back in August 2003, it was only 34.6 million miles (55.8 million km) from Earth.

From a practical point of view, Mars appears as a very tiny object in most amateur telescopes, almost always a disappointment to a beginner looking at it. The detailed images you see online are almost always made by combining hundreds of individual frames by a process called stacking, which minimizes the "noise" caused by the turbulence in Earth's atmosphere.

To see that sort of detail at the eyepiece requires tremendous patience, waiting for the rare instants when the Earth's atmosphere steadies, allowing the fine detail to pop into view. At those instants of clarity, you will see Mars' polar cap and traces of its subtle differences in terrain.

Editor's note: If you take an amazing skywatching photo of Mars or any other night-sky view, and you'd like to share it for a possible story or image gallery, please contact managing editor Tariq Malik at spacephotos@space.com.

This article was provided to Space.com by Simulation Curriculum, the leader in space science curriculum solutions and the makers of Starry Night and SkySafari. Follow Starry Night on Twitter @StarryNightEdu. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

By by Geoff Gaherty, Starry Night Education

Rare Sight: Mars, Earth and Sun Will Align Next Week