It’s a spectacle that won’t repeat for another century – the sight of Venus slowly inching across the face of the sun.

So unless scientists discover the fountain of youth, none of us alive today will likely ever witness this celestial phenomenon again, dubbed a “transit of Venus.”

It’s so unique that museums and schools around the globe are hosting Venus viewing festivities – all for a chance to see our star sport a fleeting beauty mark. Even astronauts aboard the International Space Station plan to observe the event.

The drama unfolds Tuesday afternoon from the Western Hemisphere (Wednesday morning from the Eastern Hemisphere). Venus will appear as a small black dot gliding across the disk of the sun. As in a solar eclipse, do not stare directly at the sun; wear special protective glasses.

The entire transit, lasting 6 hours and 40 minutes, will be visible from the western Pacific, eastern Asia and eastern Australia.

Skywatchers in the United States, Canada, Mexico, Central America, and the northern part of South America will see the beginning of the show before the sun sets. Europe, western and central Asia, eastern Africa and western Australia will catch the tail end after sunrise. Those who don’t want to leave their homes can follow live webcasts by NASA and various observatories.

“Anything silhouetted on the sun looks interesting. Seeing Venus is extremely rare,” said astronomer Anthony Cook of the Griffith Observatory.

Perched on the south slope of Mount Hollywood in Los Angeles, the observatory is girding for heavy traffic Tuesday afternoon as throngs were expected to peer through telescopes with special filters set up on the lawn.

Skygazers who want the full experience are flocking to Hawaii, considered one of the prime viewing spots since the whole transit will be visible. From the world-famous Waikiki Beach on Oahu to the summit of Mauna Kea on the Big Island, eclipse glasses will be passed out so that people can safely see Venus crossing without damaging their eyes.


Just remember to have patience.

“There’s no one big climatic moment. It takes longer to happen” than a solar or lunar eclipse, said Larry O’Hanlon, who does outreach at the W.M. Keck Observatory on the Big Island.

The second planet from the sun between Mercury and Earth, Venus is about the same size as Earth. It appears as one of the brightest objects in the night sky because its thick clouds reflect much of the sunlight back into space.

There will be no obvious change to the brightness of the sky during the event; Venus only blocks out a tiny fraction of the sun.

“You have to know it’s happening,” said David DeVorkin, a senior curator at the Smithsonian’s National Air and Space Museum.

Venus is the third celestial show to grace the sky in less than a month. Just a day earlier, a partial lunar eclipse will be visible from western North America, South America, Australia and eastern Asia. And there was the much-hyped “ring of fire” solar eclipse on May 20.


Unlike eclipses, Venus transits are truly rare. They come in pairs, separated by more than 100 years. The last one occurred in 2004 and next pair in 2117 and 2125.

Since the German astronomer Johannes Kepler first predicted it in the 17th century, only six have been observed. The upcoming one will be the seventh.

Only two people were said to have seen the transit of 1639. The 1882 transit was a bigger deal – people jammed the sidewalks of New York City and paid 10 cents to peek through a telescope. John Philip Sousa even composed a score called “Transit of Venus March.”

The one in 2004 was viewed by millions – in person and online.

University of Alabama astronomer William Keel was determined not to miss the 2004 transit, the first one in 122 years. But he only caught 45 minutes of the action before clouds rolled in. This time, he plans to set up telescopes on the roof and hopes for clear skies.

The early Venus viewings were a big deal to scientists who used the alignment to measure the size of our solar system. The technique is still used today to search for alien worlds outside our solar system.
SOURCE

Russia's latest weather satellite has captured the crispest-ever video of our planet - with unforgettable touches such as the sun reflecting off the sea as day turns to night.

The image was taken by the Electro-L, Russia's latest weather satellite, which has a massive resolution of 121million megapixels.

This is Planet Earth, seen from 36,000km above the surface, with the rich deep blues of the sea contrasting with the sharp outlines of land, as white clouds scurry across the skies.

The satellite captures this kind of stunning image every half-hour as it monitors our weather and, if a strange weather phenomenon is detected, the Russian operators can remotely command the satellite to take images every 10 minutes.

The images, in which each pixel represents 1km, uses a combination of visible and near-infrared wavelengths, so that vegetation shows up in red, rather than the green you might expect.

Electro-L sits in a geo-stationary orbit, which means its speed matches that of the Earth's rotation, making it remain 'motionless' above a fixed point of the planet. It launched in January 2011 and has been beaming down these stunning images ever since.
Source

The classical naked-eye planets—Mercury, Venus, Mars, Jupiter, and Saturn—can be seen easily without optical aids and so have been known since ancient times.

But the quintet hasn't appeared together during a single night since 2004.

What's more, this week's parade of planets will be joined in the nighttime skies by the waxing crescent to waxing gibbous moon and the superbright stars Sirius and Canopus.

"Although being able to see these objects simultaneously doesn't have any scientific value as such, it is a really fun opportunity to get a sense of how we fit in the universe," said Geza Gyuk, an astronomer with the Adler Planetarium in Chicago.

"It is a bit like looking at an astronomy class in a nutshell."

Best Views for Cosmic Parade

Although the moon and the seven bright objects will all be visible in one night, they won't all appear at the same time or in the same region of the sky.

The best time to catch sight of the cosmic parade will be between February 28 and March 7. This is when the more elusive planets Mercury and Mars will be at their brightest in the evening sky for 2012, and when the moon will be above the horizon for many hours before setting.

Just after local sunset, Mercury will be low in the west and rusty-colored Mars will start to rise in the east.

Catching Mercury in particular is notoriously difficult, Gyuk said, because the tiny world is the closest to the sun and so never appears very far above the nighttime horizon.


The best way to find Mercury with the naked eye will be to first identify the superbright planets Jupiter and Venus, which will appear in the southwest about 30 minutes after local sunset.

"Follow the line connecting Jupiter to Venus below right, and continue on until you almost reach the horizon," Gyuk said.

"Mercury will be in this vicinity and should be fairly bright in binoculars, but will be getting dimmer and harder to locate as the days of early March progress."


Saturn—which looks like a bright, yellowish star—will rise near local midnight in the east.

According to Gyuk, the best place to view the sky show will be from either a large field or the top of a hill with eastern, western, and southern views.

Full Show a Limited-Time Offer

Sirius and Canopus are the brightest stars visible any time year-round, but this week they'll be at their highest in the sky for 2012 soon after local dusk sets in.

Located just under nine light-years away, Sirius is the brightest star we can see from Earth and the lead star in the constellation Canis Major, the mythical "big dog" that shines high in the Northern Hemisphere's winter sky.

Canopus, the second brightest star in the sky, is part of the southern constellation Carina, the keel of the mythological ship the Argo. (Related: "'Light Echoes' From Monster Star's Eruption Found—A First.")

While Sirius is visible from all mid-latitude regions, Canopus—to the lower right of Sirius—can be seen only by observers in more southerly latitudes, for instance, below Los Angeles and Atlanta.

The northern limit for viewing the other six bright objects this week is around the Arctic Circle, beyond which Sirius is invisible. The southern limit is around the Equator, beyond which it becomes very difficult to spot Mercury.

"The moon, of course, is our closest cosmic neighbor and the only one we can really study as a world with the naked eye or even simple binoculars," Gyuk added. (Related: "New Scars Found on Moon, Hint at 'Recent' Tectonic Activity.")

"However these other points of light are all really bright objects in the sky too, so to get the full experience, take your time and let your eyes adapt to the darkness and enjoy."

Via : NationalGeographic

The moon, Venus, and Jupiter — the three brightest objects in the night sky — will be putting on a dazzling celestial show shortly after sunset both Feb. 25 and 26, coming together in a tight triangle. With any luck, you might also spot tiny Mercury down near the horizon just as the sun goes down.

People all over the world can check out the performance just by stepping outside and looking westward. If snowstorms or general chilliness drive you inside, you can always watch the spectacular event live on the Slooh Space Camera feed, starting both nights at 6:30 p.m. PST.

As an added bonus, those who tune into the web show can hear some choice scientific tidbits as Slooh’s Patrick Paolucci talks to Astronomy Magazine columnist Bob Berman and other special guests.

Planets can be distinguished from stars in the night sky because they don’t twinkle. This is because they are much closer to us and their light doesn’t get completely distorted by Earth’s atmosphere.

The planetary alignment will continue through the end of the month, with Venus and Jupiter inching ever closer. By late February, the two worlds will appear less than 10 degrees apart, able to be hidden behind an outstretched clenched fist. In March Venus and Jupiter will continue converging until, on Mar. 13, they will be only three degrees (or about two fingers) apart.

If all this isn’t enough, turn around and face eastward during this time to spot the bright red dot of Mars rising shortly after sunset. Mars will grow slightly larger in the sky as it gets nearer to Earth, coming closest around Mar. 5.

Saturn, the final planet visible to the naked eye, will appear in the east shortly before midnight during this period, shining highest in the sky in the hours leading up to dawn.


Source

On Tuesday of this week, astronomers from NASA's Kepler spacecraft made an announcement that they had discovered a pair of planets that were similar in size to the Earth that were orbiting a distant star similar to our Sun. The new planets are the smallest yet to be found beyond our solar system. One of the planets is the size of Earth and the other planet is slightly smaller than Venus.

The way Kepler works is that it detects planets by watching for blinks when they move in front of their stars. Kepler has so far discovered 2,326 potential planets, 207 that would be Earth-size if confirmed, since it was first launched in 2009. This week's discovery is important because although it has always been anticipated that there would be a discovery of an earth size planet, the significance of this means that the detection of Earth-size planets at larger distances is technically possible. It has been called a watershed moment in human history.

The two new planets, Kepler 20e and Kepler 20f, are so close to their star that they are roasting and therefore unlivable. Their star, which is slightly smaller and cooler than our Sun, is about 950 light years away from us. Kepler had previously found three larger Neptune-like planets that were also orbiting around it. The two new earth size planets are presumed to be rocky orbs that formed in the outskirts of their planetary system and then migrated inward.

The next major goal astronomers say, is to find an Earth-size planet in the correct zone of a star, where conditions are temperate for water and thus life as we know it. That time is yet to come.

Not content with unveiling 16 Super-Earths earlier this week, astronomers at NASA’s Kepler Mission revealed Thursday that they have also discovered a first of its kind — a planet that orbits two suns.

The planet is officially known as Kepler 16(AB)-b, but even astronomers are informally calling it Tatooine, after Luke Skywalker’s desert homeworld in Star Wars. You may remember the scene where Luke gazes wistfully at two setting suns — and if you’re a real space geek, you may remember that when the movie was released, astronomers publicly doubted whether such a planetary system could exist. So if today’s news is a vindication for anyone, it’s George Lucas.

Indeed, by way of apology, NASA reached out to Industrial Light and Magic visual effects supervisor John Knoll to discuss the finding at today’s official press conference. Knoll repaid the compliment: “Science is stranger and cooler than fiction,” he said. “It’s possible there’s a real Tatooine out there.”

If so, it isn’t this planet. Despite being in a binary star system, Kepler 16(AB)-b is a gas giant rather than a desert world. Somewhat similar to Saturn in size, its surface temperatures vary between minus 150 Farenheit to minus 100 on a warm day. So if there is a “wretched hive of scum and villainy” hanging out there, it has found some way of keeping toasty.

If you feel like checking it out for yourself, you’d better get moving sooner rather than later. “Tatooine” is 200 light years away, in the constellation Cygnus.

This image provided by NASA shows an artist's depiction showing a world where two suns set over the horizon instead of just one. The planet, called Kepler-16b, is the most "Tatooine-like" planet yet found in our galaxy. Tatooine is the name of Luke Skywalker's home world in the science fiction movie Star Wars.
Originally published in Mashable