"On a moonless night in a dark place, you can see your shadow in Venusian light"

Venus, Jupiter, crescent moon meeting up this weekend

[...] The last four weeks or so have been a spectacular time for stargazers, or, more precisely, planet-watchers. Venus and Jupiter have had a conjunction, and on March 13 passed so close to each other in the night sky that they could have exchanged business cards. Throw in the moon on Sunday and Monday nights and it’s a must-look situation.

“When you get a configuration like this, people who don’t normally look up above the horizon find that their eyeballs are being hijacked,” said Alan MacRobert, an amateur astronomer and senior editor at Sky & Telescope magazine.

More news is on the horizon: On June 5, Venus will transit the sun, the last such transit until 2117. With a safe solar filter, the tiny black dot of Venus will be visible as it gradually moves across the sun’s face.

[...]

What’s unfolding Sunday and Monday nights is a reprise of what happened Feb. 25 and 26, when the crescent moon slipped past Jupiter and Venus. The two planets have a conjunction like this about once every 24 years, said Geoff Chester, spokesman for the U.S. Naval Observatory.

This is what’s known as an evening apparition of Venus (it can be a morning star or an evening star), and it has been particularly sublime because the planet is relatively high in the sky. The second rock from the sun is near its greatest “elongation” — as far as it ever gets from the sun as seen from Earth — and so it’s up in the sky for a long time before it sets.

It’s also preposterously brilliant. Its magnitude is almost at the maximum for Venus — minus 4.4. (The lower the magnitude, the brighter the object.) On a moonless night in a dark place, you can see your shadow in Venusian light, Chester said.

“The circumstances for this evening apparition are about as good as they get,” Chester said. “Then you throw Jupiter into the mix, which is usually the second brightest planet, then you’ve got a couple months when the moon is playing footsie with them. And that’s what makes it particularly interesting.”

Those unfamiliar with such things should be warned that planet-watching is a subtle pleasure, enhanced by the right attitude. Not much actually happens. The planets don’t zoom around. Nothing collides or explodes. There are no cameo appearances by comets. The moon and planets will drop below the horizon by late evening and some people may feel the need to find an after-party. [...]

I have seen them on the few cloudless nights we've had recently. I thought it was dramatic.

     

Who's Missing a Planet?

We are, apparently. And not a rocky one, like the asteroid belt might have been formed from. THIS missing planet was supposedly a Gas Giant:


Did our solar system once harbor an extra planet?

A computer simulation has shown that our solar system couldn't have formed without an extra planet. But if that theory is true, what happened to it?

A new study based on computer simulations has demonstrated that our solar system might be missing a planet. In fact, without an extra planet, it seems unlikely that our solar system could have formed at all, reports PhysOrg.com.

The startling discovery suggests that Jupiter, Saturn, Uranus and Neptune were not the only gas giant planets around during the formation of our solar system. There had to be a fifth gas giant, similar to Uranus and Neptune, orbiting some 15 times further from the sun than our planet Earth.

David Nesvorny from Colorado’s Southwest Research Institute reached the conclusion after performing around 6,000 computer simulations about the formation of the solar system, nearly all of which required the extra planet to work. Almost all of the simulations that factored in only the planets we know of in our solar system showed the four gas giants violently destroying one another. In the few simulations in which they survived, several of the rocky planets, such as Earth, were destroyed instead.

After adding the mysterious fifth planet, Nesvorny was able to greatly improve the odds of our solar system forming as we currently know it.

So the question remains: if our solar system is missing a planet, what happened to it?

The computer simulations also explain the fifth planet's fate. [...]

Read the whole thing to find out.

Interesting. Theoretical, but interesting.
     

The Planets Line Up with the Moon

Well at least they did. Actually, this morning was the last chance to see them lined up with the Moon. But then planets themselves will continue to be lined up for a couple of weeks:

Six Planets Now Aligned in the Dawn Sky

If you get up any morning for the next few weeks, you’ll be treated to the sight of all the planets except Saturn arrayed along the ecliptic, the path of the sun through the sky.

For the last two months, almost all the planets have been hiding behind the sun, but this week they all emerge and are arrayed in a grand line above the rising sun. Mercury, Venus, Mars, and Jupiter are visible, and you can add Uranus and Neptune to your count if you have binoculars or a small telescope.

[...]

While astrologers view planetary alignments as foretellers of disasters, modern amateur astronomers look forward to them as nothing more than grand photo ops.

If you go out any morning for the next four days, you’ll be treated to a view of the crescent moon and all but one of the naked eye planets.

Because the moon moves rapidly from one morning to the next, it will only be part of the lineup for the next four mornings, but the four naked-eye planets will be there for the next few weeks.

Venus is, as always, the brightest and most visible of the planets, and it can be your guide to spotting the others. About half way between Venus and the rising sun is Jupiter, the second brightest planet.

Mars will be a tiny speck just above Jupiter, and Mercury another tiny speck about half way between Jupiter and Venus. Uranus is slightly more than one binocular field above and to the right of Venus, and Neptune is much farther to the right, about 40 degrees away in Aquarius. The Moon will be just above Venus on Saturday morning, and just above Jupiter and Mars on Sunday morning. [...]

I read somewhere that ancient peoples thought it was a bad omen, because they believed the planets were gods. Ignorance believes all kinds of things.

The article also mentions that there will be no planetary lineup occurring in 2012, no matter what the New Age Dingbats claim. So enjoy it while you can ;-)
     

Photos of Mercury from the Messenger Probe

Apparently it took years to arrive there, because it had to follow a convoluted path to avoid being destroyed by the sun's gravitational pull.


First photos of Mercury from orbit

There are 19 pics. Some in color, but not a lot of color to see. Some purple, blue and beige tinges. Mostly grey, looks a lot like the moon at first, but there are significant differences. The photo quality is MUCH better than the old photos from the Mariner mission. And it has a lot more than just cameras, measuring all kinds of new data. Did you know Mercury has an atmosphere?




It's a planet with plenty of mysteries yet to be revealed.

Secrets of Mercury

The closest planet to our sun, and the smallest in the solar system, is also one of the least understood. Compared to more glamorous planets like Mars, Jupiter and Saturn, Mercury has received much less attention from scientific study missions. But NASA's Messenger probe is set to reveal the secrets behind the odd planet. The probe has flown by Mercury three times and will enter orbit around the planet in March — the first spacecraft ever to do so.

Here's a look at some of Mercury's most enduring mysteries. In the words of Messenger science team member Robert Strom, "The best is yet to come. What you're seeing here is just the tip of the iceberg." [...]

I find it all fascinating, and will continue to follow it with great interest.
     

An "Earth-Like" new world discovered?

I think they might really be stretching the meaning of "earth-like".

From the British Daily Mail online:
Found 20 light years away: the New Earth

[...] "Because of its temperature and relative proximity, this planet will most probably be a very important target of the future space missions dedicated to the search for extraterrestrial life."

Gliese 581 is among the closest stars to us, just 20.5 light years away (about 120 trillion miles) in the constellation Libra. It is so dim it can be seen only with a good telescope.

[...]

It has a mass five times that of Earth, probably made of the same sort of rock as makes up our world and with enough gravity to hold a substantial atmosphere.

Astrobiologists - scientists who study the possibility of alien life - refer to a climate known as the Goldilocks Zone, where it is not so cold that water freezes and not so hot that it boils, but where it can lie on the planet's surface as a liquid.

[...]

The surface gravity is probably around twice that of the Earth and the atmosphere could be similar to ours.

Although the new planet is in itself very Earth-like, its solar system is about as alien as could be imagined. The star at the centre - Gliese 581 - is small and dim, only about a third the size of our Sun and about 50 times cooler.

The two other planets are huge, Neptune-sized worlds called Gliese 581b and d (there is no "a", to avoid confusion with the star itself).

The Earth-like planet orbits its sun at a distance of only six million miles or so (our Sun is 93 million miles away), travelling so fast that its "year" only lasts 13 of our days.

The parent star would dominate the view from the surface - a huge red ball of fire that must be a spectacular sight.

It is difficult to speculate what - if any - life there is on the planet. If there is life there it would have to cope with the higher gravity and solar radiation from its sun.


Just because Gliese 581c is habitable does not mean that it is inhabited, but we do know its sun is an ancient star - in fact, it is one of the oldest stars in the galaxy, and extremely stable. If there is life, it has had many billions of years to evolve.

This makes this planet a prime target in the search for life. According to Seth Shostak, of the Search for Extraterrestrial Intelligence Institute in California, the Gliese system is now a prime target for a radio search. 'We had actually looked at this system before but only for a few minutes. We heard nothing, but now we must look again.'

By 2020 at least one space telescope should be in orbit, with the capability of detecting signs of life on planets orbiting nearby stars. If oxygen or methane (tell-tale biological gases) are found in Gliese 581c's atmosphere, this would be good circumstantial evidence for life.

Dr Malcolm Fridlund, a European Space Agency scientist, said the discovery of Gliese 581c was "an important step" on the road to finding life. [...]

The article is full of all sorts of details. The scientists are speculating a lot though; speculating is not facts. Still, some of their educated guesses are interesting, and the data they can collect does present a lot of possibilities.

While the planet isn't truly like earth, it may be earth-like in the sense that it comes closer to being like earth than any other planet we've been able to detect.

As technology advances, I'm sure we will be able to observe more, even from such a far distance. But to really find things out, we'll have to go there. And that, I expect, is a long ways off!