Finding a Habitable Planet

September 30, 2010 at 10:54 am | 5 Comments

Not Too Far Away

An artist's concept by Lynette Cook of the planet found around Gliese 581.

The news of a new planet only three times the size of Earth and orbiting in its star’s potentially habitable zone spurs on the great speculation that it’s only a matter of time before we find a planet with some sort of life on it.

The star is called Gliese 581, a red dwarf that lies only 20 light-years from Earth. The planet is called Gliese 581g. This discovery was the result of more than a decade of observations using the W. M. Keck Observatory in Hawai’i.

Finding a planet in a potentially habitable zone means that the planet lies in an orbit around the star that is just far enough away (but not too far away) that liquid water could exist on the planet’s surface.  That water hasn’t yet been found on the Gliese 581g, but the fact that it’s in the right place — the so-called “Goldilocks zone” is important.

Water is one of the prime ingredients for life, along with warmth and organic material.  If water is eventually found on the newly discovered planet, that would make it the most Earth-like exoplanet yet discovered and the first strong case for a potentially habitable one.  To astronomers, a “potentially habitable” planet is one that could sustain life, not necessarily one where humans would thrive.  Having habitable status depends  on more than just water and an atmosphere, but those two factors really raise the odds of the planet being hospitable to life.

So, how did astronomers find this planet?  The research is based on 11 years of observations of Gliese 581 using the HIRES spectrometer on the Keck I Telescope. That instrument lets astronomers make precise measurements of a star’s radial velocity (its motion along the line of sight from Earth). Changes in that radial velocity might indicate that something is tugging on the star, inducing slight changes in its motion in space.  The gravitational influence of an orbiting planet is one reason why we might see periodic changes in the radial velocity of a host star. Multiple planets induce complex wobbles in the star’s motion, and astronomers use sophisticated analyses to detect planets and determine their orbits and masses.

NO Intelligent Life.. or Any Life… Yet

As you might expect, some commentators and reporters in the media and Web-based React-O-Sphere are already breathlessly reporting the discovery of life on that planet.   It isn’t so.  Hasn’t been found. Yet.  The discovery is of a “potentially habitable planet” not an inhabited one. There’s a distinct difference when you stop to think about it.

But, that hasn’t stopped the React-O-Sphere from saying it.  It tells me that those commentators either didn’t read the press releases carefully or didn’t understand them.  This story is a great case for the value of reading comprehension on the part of the media and Web commentators.

For the straight scoop on what HAS been found, check out the link at the top, or go here or here.  That way you can get more of the story — straight from the sources who made the discovery.

Raise Your Hand if You Think Space is Pristine

September 28, 2010 at 12:51 pm | 2 Comments

It’s Not

We all carry around in our heads this vision of interplanetary space as dark, cold,  lonely, devoid of stuff.  Well, it is. Except for all those planets, moons, rings, comets, and asteroids.  And dust.  And charged particles from the solar wind. Other than all that material, yeah, the space around the planets looks empty. But, it’s not.  Don’t be fooled.  Our solar system is full of stuff and we’re learning more about it all the time.

Some of the “stuff in empty space” comes close to Earth pretty often. There’s nothing mysterious about that.  There are many asteroids orbiting in the solar system, some far away, others in Earth’s neighborhood. It’s no surprise that astronomers spot wandering chunks of rock that sometimes come close to Earth.  Now that we have more cameras looking for such material — cameras and instruments that are sensitive to the faint light these things reflect — we are spotting more of them.  It doesn’t mean there’s MORE of that stuff out there all of a sudden. It’s always been there.  We just haven’t always had the instrumentation to find it.  Now we do, and the sudden prevalence of near-Earth asteroid discoveries simply means that now that we can spot those objects, we ARE spotting them.

Asteroid 2010 ST3 (circled in green) taken by PS1 on the night of September 16 moving against the background field of stars and galaxies. Each image is about 100 arc seconds across. Credit: PS1SC

The University of Hawai’i’s Pan-STARRS PS1 telescope just discovered an orbiting chunk of rock that will come within 4 million miles of our planet in mid-October.  It’s not a huge chunk — not planet-sized or even moon-sized. It’s about 150 feet across — enough to make a prominent entry into our atmosphere. It’s likely it would break up in the atmosphere, but there would still be a blast wave on the surface that would devastate several hundred miles of territory.

Now, this object, called 2010 ST3 is NOT going to enter our atmosphere on this pass.  But, it could (and I stress the word “COULD” because there ARE people who will take this as a sign of the impending apocalypse and start raising all kinds of irrelevant points no matter how carefully one points out that “could” and “will” are not semantically equal) hit Earth in 2098 and cause damage. But, it’s not going to hit this time, even though it is potentially hazardous. It’s one of many, many chunks of solar system that are orbiting out there, part of the system of solar system objects that astronomers are still learning about, counting, charting, categorizing, and warning us about.  Learning about objects like 2010 ST3 is part of planetary science and part of the exploration of our solar system.

‘Tis Talk Like a (Starry) Pirate Day! Ahoy!!!

September 18, 2010 at 20:23 pm | Leave a Comment

Ahoy There, Me Stargazin’ Hearties!!!

The Official Pirate Star Pattern!

The Official Pirate Star Pattern!

Yarrrr, ye lasses and lads of the starry deeps! Time for me annual September 19 celebration of “Talk Like a Starry Pirate Day” message! Today is indeed Talk Like a Pirate Day, which means ye can affect all FUN piratey attitudes (but NOT the pillagin’ and other law-breakin’ activities–those are frowned upon in TLAPD circles). “All in good fun” is the piratey watchword.

Do astronomers celebrate “Talk Like a Pirate Day”?

Welll… aye, of course they do.

How to celebrate TLAPD if yer an astronomer? Well, stargazin’ like a pirate is always in good form. First, wait til it gets dark (if ye want to see stars). If ye want to see just one star, then go outside and pretend yer on a desert isle with yer piratey treasure and make sure ye have yer eye patch on!  Oh, and a pair of piratey sunglasses!

Count yer doubloons and cackle with glee. And, let the sunshine warm ye, but do not be a chumbucket and actually LOOK at the Sun — it’ll mess with yer eyes somethin’ fierce! Just enjoy it, and as Captain Jack warns ye, wear sunblock!

Nighttime starlubbers should wander out after the Sun’s been down fer a while (darkness is a good clue) –and look up! Check out the stars. Look for a piratey planet! This year, the King o’ The Piratey Planets is up — Jupiter!  See if ye can spot the Milky Way.  It’s the milky band o’ whiteness running almost overhead this time o’ year!

That’s all there is to sailin’ the starry seas! Oh, and ye must talk like a piratey astronomer! Every once in a while say something like “Shiver me timbers, look at Jupiter there!” or “Yarrrrr…. will ya look at that Milky Way!” or “Take this telescope to the Lagoon Nebula, me hearties!!!” Or, challenge yer hearties to see who can find the “Black Eye Nebula” (M64 for ye geeks in the audience).

Wear somethin’ warm (even pirates’ timbers get shivered in cool night air), and if ye like, bring a grog or other beverage (our personal favorite is piratey hot chocolate). After yer done, go back inside and watch a good piratey movie. Pirates of the Caribbean comes to mind, or maybe even Aye, Robot, or Men in Blackbeards. Or maybe Yarrrrrrr Wars… or one of my personal favorites, The Pirate Wears Prada… or Mutiny on the Bounty Hunter or Around the World With 80 Pirates or Bravehearty… ye get the idea!!

The Hole at the South Pole

September 16, 2010 at 11:40 am | Leave a Comment

The Ozone Hole

Earth's ozone hole, from data provided by NASA's Goddard Space Flight center and the Ozone Hole Watch. The blue area is the 'ozone hole', where the density of the ozone layer is at its thinnest this time of year.

One of the best things that NASA does (along with other space agencies) is give us a look at our own planet — as a planet.  That is, the scientists who study our world do so in the same way they would study any other planet. They chart changes on the surface, map atmospheric activity, and chart all those changes over time.  For the past decades, scientists have charted something called the ozone hole, which forms over the south pole of our planet each year.  This image shows what the ozone looks like as of September 13, 2010, courtesy of the OzoneWatch website.

Satellite instruments monitor the ozone layer, and scientists use the data to create the images that indicate the amount of ozone in the upper atmosphere. The blue and purple colors are where there is the least ozone, and the greens, yellows, and reds are where there is more ozone.  The depth and size of this Antarctic ozone hole are affected by the temperature of the stratosphere (the upper part of Earth’s atmosphere) and the amount of sunlight that bathes the south polar region.

So, why is ozone such an important thing to monitor? This is a useful gas for the protection of life on this planet.  In the upper atmosphere, ozone acts to absorb ultraviolet-B emissions.  Such emissions, which come primarily from the Sun, can harm living systems. It’s safe to say that, without the ozone layer in our upper atmosphere, life on Earth would be severely harmed.  In fact, without the ozone layer, it’s possible that life wouldn’t have formed on this planet.  So, losing a chunk of our ozone layer each year is a big deal.  Scientists want  understand why this happens.

Now the good news is that the ozone layer is not thinning anymore — after more than half a century of actively thinning.  This is due to a ban on harmful chemicals that have damaged the ozone  layer.

We know that ozone is destroyed by chlorine- and bromine-containing chemical compounds.  We know that some aircraft emissions hurt the ozone layer.  We know a lot of different reasons why our ozone layer is under attack, not just from the Sun, but from below by the sentient life forms that inhabit the planet.

Sure, there are naturally occurring attacks on the ozone, but the largest attack comes from human activity. We use huge amounts of chemical compounds in industrial and home-based products. You may have heard of what’s referred to as chlorofluorocarbons. They escape to the atmosphere from refrigeration and propellants.  They persist for years in the lower part of the atmosphere, and eventually some migrate to the upper atmosphere. It’s a long-term process because the destruction of ozone doesn’t happen the minute CFCs get into the atmosphere.  But, it does eventually happen. So, even though we HAVE reduced our use of these compounds — the damage from the reservoir of ozone-destroying atoms and molecules has continued.  The damage that now shows up in the ozone hole probably comes from materials released well into the last century. With luck, and the continued ban on these chemicals, the ozone should get back to its 1980 levels by mid-21st century.

I know that there are still people who deny such problems existed — generally they are people who don’t want to believe that humans can have a deleterious effect on our planet’s ecosystems. The problems won’t go away because some people bury their heads in the sand. Oh, sure, their faces won’t get sunburned by the UV-B, but their hineys will.

So, what’s the effect of the loss ozone? Ask the people who live under that hole and who are at higher risk for cancer and other conditions that are caused or exacerbated by exposure to ultraviolet-B.  I was in South America a few years ago, at the very tip of the continent. The people who live there know first-hand what it’s like to live under a thinning ozone layer.  Sunblock is a constant friend.  Children are warned NOT to go out with out adequate clothing and sunblock.  If you want to know what life would be like on this planet with a thinner (or nearly nonexistent) ozone layer, talk to the children of Patagonia.

And, thanks to NASA and other agencies who continually monitor our planet from space (another fine example of how space exploration benefits us here at home), we might be able to learn enough to avoid dissipating our ozone layer more than it already is.

Observe the Moon

September 15, 2010 at 20:26 pm | Leave a Comment

You Can’t Miss It!

The Moon, as seen from the International Space Station. Courtesy NASA.

Do you like to look at the Moon?  It’s a great object to study — whether with the naked eye or binoculars, or with a telescope (if you have one).  On September 18 (this Saturday), all the Moon gazers around the world will join together to celebrate the first of what they hope will be many “International Observe the Moon Nights“.

The Moon is so close, yet so far away from us.  It takes about  1.3 seconds to send a light beam between Earth and the Moon. If you wanted to travel there, it would take more than a day (and more likely a couple of days at the least). And, once you got there, you’d have to live in a space suit, bring along your own food and water, and — if you wanted to build a home there — you’d have to live underground for your own safety.  The lunar surface is covered with craters and coated with dust. It’s not very hospitable at all — but, humans have wanted to travel there. And, in the 1960s and 1970s, humans DID go to the Moon.  We aren’t back there yet, but hopefully someday we will be.  It’s a worthy goal for any traveler. For now, though, we can observe it easily from our backyards.  Hence, the celebration of International Observe the Moon Night.

The best part about the celebration is that you don’t have to be an experienced skygazer.  It’s for anybody — from the general public to amateur astronomers to professionals — to gaze at the Moon.  Check out the festivities at the link above — where you’ll find a history of the event and some forms to fill out if you participate.  I can’t think of a better way to spend a September evening! Can you?

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Image of Horsehead Nebula: T.A.Rector (NOAO/AURA/NSF) and Hubble Heritage Team (STScI/AURA/NASA)

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