Earthlike Planet Discovered. The First of its Kind. Chances of Life 100% ?

This artist's conception shows the inner four planets of the Gliese 581 system and their host star, a red dwarf star only 20 light years away from Earth. The large planet in the foreground is the newly discovered GJ 581g, which has a 37-day orbit right in the middle of the star's habitable zone and is only three to four times the mass of Earth, with a diameter 1.2 to 1.4 times that of Earth.
Credit: Lynette Cook

By Jeanna Bryner
LiveScience Managing Editor. Space.Com

An Earth-size planet has been spotted orbiting a nearby star at a distance that would makes it not too hot and not too cold — comfortable enough for life to exist, researchers announced.

If confirmed, the exoplanet, named Gliese 581g, would be the first Earth-like world found residing in a star's habitable zone — a region where a planet's temperature could sustain liquid water on its surface.

And the planet's discoverers are optimistic about the prospects for finding life there.

"Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say, my own personal feeling is that the chances of life on this planet are 100 percent," said Steven Vogt, a professor of astronomy and astrophysics at the University of California, Santa Cruz, during a press briefing today. "I have almost no doubt about it."

His colleague, Paul Butler of the Carnegie Institution of Washington, in Washington, D.C., wasn't willing to put a number on the odds of life, though he admitted he's optimistic.

"It's both an incremental and monumental discovery," Sara Seager, an astrophysicist at the Massachusetts Institute of Technology, told SPACE.com. Incremental because the method used to find Gliese 581g already has found several planets most of the known planets, both super-Earths, more massive than our own world outside their stars' habitable zone, along with non-Earth-like planets within the habitable zone.

"It really is monumental if you accept this as the first Earth-like planet ever found in the star's habitable zone," said Seager, who was not directly involved in the discovery.

Vogt, Butler and their colleagues will detail the planet finding in the Astrophysical Journal.

The newfound planet joins more than 400 other alien worlds known to date. Most are huge gas giants, though several are just a few times the mass of Earth.

Stellar tugs

Gliese 581g is one of two new worlds the team discovered orbiting the red dwarf star Gliese 581, bumping that nearby star's family of planets to six. The other newfound planet, Gliese 581f, is outside the habitable zone, researchers said.

The star is located 20 light-years from Earth in the constellation Libra. One light-year is about 6 trillion miles (10 trillion km).

Red dwarf stars are about 50 times dimmer than our sun. Since these stars are so much cooler, their planets can orbit much closer to them and still remain in the habitable zone.

Estimates suggest Gliese 581g is 0.15 astronomical units from its star, close enough to its star to be able to complete an orbit in just under 37 days. One astronomical unit is the average distance between the Earth and sun, which is approximately 93 million miles (150 million km).

The Gliese 581 planet system now vaguely resembles our own, with six worlds orbiting their star in nearly circular paths.

With support from the National Science Foundation and NASA, the scientists — members of the Lick-Carnegie Exoplanet Survey — collected 11 years of radial velocity data on the star. This method looks at a star's tiny movements due to the gravitational tug from orbiting bodies.

The subtle tugs let researchers estimate the planet's mass and orbital period, how long it takes to circle its star.

Gliese 581g has a mass three to four times Earth's, the researchers estimated. From the mass and estimated size, they said the world is probably a rocky planet with enough gravity to hold onto an atmosphere.

The planet is tidally locked to its star, so that one side basks in perpetual daylight, while the other side remains in darkness. This locked configuration helps to stabilize the planet's surface climate, Vogt said.

"Any emerging life forms would have a wide range of stable climates to choose from and to evolve around, depending on their longitude," Vogt said, suggesting that life forms that like it hot would just scoot toward the light side of that line while forms with polar-bear-like preferences would move toward the dark side.

Between blazing heat on the star-facing side and freezing cold on the dark side, the average surface temperature may range from 24 degrees below zero to 10 degrees Fahrenheit (minus 31 to minus 12 degrees Celsius), the researchers said.

Are you sure?

Supposedly habitable worlds have been found and later discredited, so what makes this one such a breakthrough?

There's still a chance that further observations will dismiss this planet, also. But over the years, the radial velocity method has become more precise, the researchers point out in their journal article.

In addition, the researchers didn't make some of the unrealistic assumptions made in the past, Seager said.

For instance, another planet orbiting Gliese 581 (the planet Gliese 581c) also had been considered to have temperatures suitable for life, but in making those calculations, the researchers had come up with an "unrealistic" estimate for the amount of energy the planet reflected, Seager pointed out. That type of estimate wasn't made for this discovery.

"We're looking at this one as basically the tip of the iceberg, and we're expecting more to be found," Seager said.

One way to make this a reality, according to study researchers, would be "to build dedicated 6- to 8-meter-class Automated Planet Finder telescopes, one in each hemisphere," they wrote.

The telescopes — or "light buckets" as Seager referred to them — would be dedicated to spying on the nearby stars thought to potentially host Earth-like planets in their habitable zones. The result would be inexpensive and probably would reveal many other nearby potentially habitable planets, the researchers wrote.

Beyond the roughly 100 nearest stars to Earth, there are billions upon billions of stars in the Milky Way, and with that in mind, the researchers suggest tens of billions of potentially habitable planets may exist, waiting to be found.

Planets like Gliese 581g that are tidally locked and orbit the habitable zone of red dwarfs have a high probability of harboring life, the researchers suggest.

Earth once supported harsh conditions, the researchers point out. And since red dwarfs are relatively "immortal" living hundreds of billions of years (many times the current age of the universe), combined with the fact that conditions stay so stable on a tidally locked planet, there's a good chance that if life were to get a toe-hold it would be able to adapt to those conditions and possibly take off, Butler said.

Another Post on Space Center History.

Hello Troops,
This post was written by David Andrus, a former Space Cadet and Volunteer at the Space Center (not to mention an all around good guy). Thank you David for taking the time to write another chapter in the Center's history.

And Now David's Post:

A call for old timers' posts? You sure you want to do that Vic? I'm one of the oldest of the old and I was hoping to save some of this for free private mission blackmail or something.

How about a recollection from my first ever trip to the space center? I think the trip was in 5th grade. That would have been either late 1990 or early 1991. The trip was organized by Fred Olson who was teaching at Sunset View Elementary in Provo at the time. I didn't know exactly what it was before I arrived at Central Elementary, just that it was some sort of space camp.

I remember first coming into the briefing room and sitting down at a desk. There was some sort of mission briefing by a guy who looked suspiciously like the current space center director...but there was just a little bit less of him and his hair was a different color (sorry Vic, I couldn't resist).

I sat there in the briefing room and looked around. The thing that really caught my attention was this rather strange door. It was lower than normal and there were some letters above it. I can't remember what they said now, but they were an abbreviation for something. I was completely clueless about what those letters meant and what was beyond that door, but boy did I ever want to know (and boy was I disappointed to learn the reason for the door being so short - there's a beam or something there that couldn't be moved to accommodate the Voyager).

I recall being taken on board the ship via the transporter on the stage, and then taking the scenic route through the control room on my way to the bridge. I took my station, which was in the same position as the current sensors station, at right wing. We handled propulsion, transporters, and a few other things I can't remember now. I also remember that all of our computers were identical and we had to click on our actions all at the same time.

Ah those old Mac classics were things of beauty. Slow, plodding, tiny black and white screens. But the technical limitations weren't important. The important part was how I was drawn into the story by feeling like I was a part of the action. We'd make a change to the ship's speed and the viewscreen and sound effects would change to reflect that we'd gone from sub-light to warp. We followed our captain's orders and actually managed to make it through without dying once.

I could go on and on about my various experiences at the space center. Maybe some day I'll collect all of my thoughts and send them on. But my continued ramblings will have to wait for another day as I'm sure I've exceeded even the attention span of our illustrious leader. Maybe I'll next regale you all with the story of how the illustrious Fish and I met and started a friendship that is now over 18 years strong.

No Bucks, No Buck Rogers. Until now.

Congress Takes Action on Space Funding
By Mark Daymont
Space Center Educator / Flight Director

It has taken over a year. When President Obama unveiled his plans for NASA's new direction, it set off a firestorm of complaints, praise, arguments and confusion. For many space enthusiasts, it seemed he was deliberately shutting down our only actual plans for continuing human spaceflight and surrendering our lead in space exploration to other countries. To other advocates, his plan seemed to put NASA on a flexible path to developing the new technologies we would use in the future. To be honest, it was a bit of both. The problem was, his plan definitely would have resulted in a longer "space gap" where the US did not have it's own ability to launch humans in space, and worse, there would have been a greater number of layoffs for specialists and engineers from the program.

Late last night, just as Congress prepared to adjourn so they could return home to campaign before the November election, they finally voted on and passed Senate Bill S.3729. This last vote now sends the bill to the President's desk for his signature. Once that is done, the Bill passes into law and the provisions therein become enacted. The money will begin to flow. The actions will be taken, the direction assured.

Many members of congress were not satisfied with the Bill. Many felt it was a poor compromise of the many, many ideas that had been bantered around, argued over and revised time after time. But most felt the time was right to do SOMETHING, and get NASA moving in a direction that felt better than what the White House was choosing. The final vote was 304 for passage, 118 against, with 10 not voting.

The Bill funds one more launch of the shuttle after two that are currently scheduled. It also anticipates helping the private sector develop commercial launchers to put astronauts and other payloads into orbit.

Funding also would go for starting to develop a new heavy launcher, which would be crucial for sending Astronauts to an asteroid of Mars, but also the International Space Station.

Seven billion dollars have been earmarked for work aimed at making the new heavy launcher operational by 2016.