Voyager 1: Outward Bound

(From NASA/JPL-Caltech, used w/o permission.)
"This artist's concept shows NASA's Voyager spacecraft against a field of stars in the darkness of space. The two Voyager spacecraft are traveling farther and farther away from Earth, on a journey to interstellar space...."

Voyager 1 is outside the heliopause, outward bound. The robot spacecraft is still about one seventh as far from Earth's star as Sedna will be about 11,400 years from now. That'll be the year 13476, give or take: by which time humanity may have long since caught up with the Voyager probes, and that's almost another topic.

About 40,000 years from now, Voyager 1 will be 1.6 light years from AC +79 3888, and a tad farther from Sol, Earth's star. Gliese 445 is a shorter name for AC +79 3888, and whatever name you prefer: it'll be about 3.45 light-years from Sol when Voyager 1 goes past. You'll still need a telescope to see it, if you're on Earth at the time: which is unlikely, come to think of it.

The Lemming didn't find any planets listed for Gliese 445, but scientists are still sorting through data: and nowhere near finished with collecting more about Earth's neighbors. They'll probably be adding new planets to their catalogs for years. Decades. Centuries. Millennia. Longer.

Anyway, right now here are some pretty good places to check out if you're looking for nearby planets:

• The Extrasolar Planets Encyclopaedia
  The exoplanet TEAM
• NASA Exoplanet Archive
  CalTech
• SIMBAD Astronomical Database
  Strasbourg University

"Nearby" on a cosmic scale, of course.

Here's what Gliese 445 looks like, as seen through a telescope on Earth. That colored ring isn't part of the star: someone drew it on the photo so you'd know which dot is yet another name for AC +79 3888. Actually, it's an abbreviation of Gliese, and the Lemming's mind is wandering.


(From Caltech/Palomar Observatory, via NASA, used w/o permission.)
"At the center of this image is the star AC +79 3888, also known as Gliese 445, located 17.6 light-years from Earth. NASA's Voyager 1 spacecraft, which is on a trajectory out of our solar system, is headed toward an encounter with AC +79 3888. In about 40,000 years, Voyager 1 will be closer to this star than our own sun.

"The image was taken by the Oschin Schmidt Telescope near San Diego, Calif., on April 22, 1998. This telescope is operated by the California Institute of Technology and Palomar Observatory."

It occurs to the Lemming that Voyager 1 may not make it to its flyby of Gliese 445. 40,000 years is a long time, humans are already working on a prototype warp drive, and that robot spaceship would make a dandy exhibit for some museum.

More:

• "Voyager: The Interstellar Mission"
  JPL/NASA
• "Gliese 445"
  Wikipedia
• "Heading toward Gliese 445"
  NASA Mission Pages, Voyager (September 12, 2013)
• "NASA Voyager Statement about Competing Models to Explain Recent Spacecraft Data"
  NASA Mission Pages, Voyager (August 15, 2013)
• "Voyager Solar System 'exit' debated"
  Jonathan Amos, BBC News (March 20, 2013)

Slightly-related posts:

• Peering into vastness
  • "Nearby Worlds, and a Cosmic Horizon"
    A Catholic Citizen in America (January 3, 2014)
    Particularly
    • Plato, Aristotle, and Getting a Grip
    • Across the Horizon, Toward Infinity
  • "Gliese 677C, Revisted: Three Super-Earths in the Habitable Zone"
    (June 28, 2013)
  • "DNA, Voyager 1, Habitable Worlds, and the Universe"
    A Catholic Citizen in America (March 22, 2013)
    Particularly
    • "We've Never Been There Before...."
  • "GJ 667Cc: Heavier than Earth, Maybe About as Warm"
    (February 6, 2012)
  • "Two Decades Later: Voyager 1 Flyby of Triton, August 21, 1989"
    (August 21, 2009)
• Getting there
  • "Warp Drive: Silly as Thinking People can Fly"
    (May 17, 2013)
  • "Warp Drive: Imagined and Real (Maybe, Eventually)"
    A Catholic Citizen in America (May 24, 2013)
  • "Quantum Entanglement and a Babbling Lemming"
    (May 3, 2013)
  • "Another Step Closer to a Practical Warp Drive: Maybe"
    (November 30, 2012)
    Particularly
    • Travel to the Stars
    • Weird Physics, Warp Drive, News, and NASA
  • "Antimatter Rocket Motor: Physics, Straightforward; Engineering, Not So Much"
    (October 26, 2012)

The Lemming Takes a Vacation

Editor's Note:

It has come to our attention that Lemming has taken an unexpected, and unannounced, vacation. We apologize for the absence of a post last week, and regret any inconvenience which this may have caused.

In lieu of the regularly scheduled post, we present an infographic which the Lemming left on his desktop, together with a somewhat enigmatic note which read, "having a great time, wish you were here."

Now, without further ado, the previously mentioned infographic:

"Alpha Centauri Stars & Planet Explained: Our Nearest Neighbors (Infographic)"
Karl Tate, Space.com (October 16, 2012)
(Size reduced to fit this blog's format)



Related posts:

• "Betelgeuse, Stellar Wind, and Exploding Eggs"
  (February 8, 2013)
• "WR 104: Gamma Ray Bursts and a Musing Lemming"
  (January 4, 2013)
• "Alpha Centauri B: New Planet"
  (October 19, 2012)
• "Gliese 581d: Rocky, Close (sort of), and Liquid Water (could be, maybe)"
  (May 18, 2011)
• "Our Sun's Sunspot Cycle Isn't All That Predictable"
  (June 16, 2010)

Betelgeuse, Stellar Wind, and Exploding Eggs

"Supergiant Star Betelgeuse to Crash Into Cosmic 'Wall' "
Miriam Kramer, Space.com (January 25, 2013)


(From ESA / Herschel / PACS / L. Decin et al, via space.com, used w/o permission.)
"In about 5,000 years, Betelgeuse is going to run straight into a line of dust (left)...."

"The red supergiant star Betelgeuse in the famed constellation Orion is on a collision course with a strange wall of interstellar dust, with the clock ticking down to a cataclysmic cosmic smashup in 5,000 years, scientists say.

"A new image of Betelgeuse by the European Space Agency's infrared Herschel space observatory, shows that the star will crash headlong into a trail of space dust while speeding through its part of the cosmos at a blistering 18.6 miles (30 kilometers) per second. That's about 66,960 mph (107,761 kph).

"Betelgeuse is a giant star that makes up the left shoulder of the Orion constellation and can easily be seen from Earth with the unaided eye by observers in the Northern Hemisphere. The star appears as a reddish-orange light above and to the left of Orion's belt...."

Betelgeuse is roughly 640 light years away: fairly close on a cosmic scale, but sufficiently distant from Earth to make the coming collision a matter for curiosity, not concern.

Astronomers have been learning quite a bit about the universe, particularly in the last century or so. That's bothered some rather tightly-wound folks, but the Lemming doesn't mind knowing that there's a whole lot of time and space. And that's another topic.

What's That?

"... The new Herschel observatory image shows Betelgeuse as a bright disk surrounded by a shield-like arc of gas as it approaches an odd bar-like wall of dust.

"The curved 'shield' formations to the left of the star are actually structures shaped by Betelgeuse's solar wind - the charged particles each star emits and blows out into the galaxy, ESA officials said. But the wall of dust the star will crash into may be anything, from a filament linked to the galaxy's magnetic field to a stellar cloud. Scientists do not think the dust wall is part of the Betelgeuse star structure.

"After the first bow of solar wind hits the line of dust in 5,000 years, Betelgeuse itself should run into the bar 12,500 years after that...."

Scientists have quite a bit of time to study that whatever-it-is before the solar (stellar?) wind from Betelgeuse starts stirring it up. Based on previous experience, the Lemming suspects that folks will be surprised by what happens. Which is just as well, since if we knew everything humanity wouldn't have much use for curiosity. More topics.

Back to Betelgeuse: the star is really big, and has been running through its hydrogen at a phenomenal rate. Soon, it'll run out. Without hydrogen to keep its fusion 'fire' going, the core of Betelgeuse will start cooling down: and, more to the point, stop providing the pressure that keeps Betelgeuse from collapsing.

That's when things get interesting. As all that tonnage of star-stuff falls inward, the star's core heats up: a lot. The physics is a trifle complicated, but basically the collapsing star works like a whacking great diesel engine: fusing lighter elements into heavier elements and releasing a phenomenal amount of energy in the process. Not that diesel engines fuse nuclei together, the reactions in that case are chemical. And that's, you guessed it, another topic.

The Lemming was making a point. What was it? Diesel engines. Stellar physics. Energy. Right.

All that energy released by fusing elements together heats up the collapsing star's core. The effect is sort of like what happens when you microwave an egg: which the Lemming does not recommend. Except that instead of spattering hot egg, most of the star gets spattered into space. It's a spectacle best viewed from a safe distance: a couple dozen light years should be enough.

Unless scientists are wrong about most of stellar physics, which doesn't seem likely, Betelgeuse will explode 'soon.' That Space.com article says in about 1,000,000 years: which is 'soon,' compared to how long this universe has been around. On the other hand, Betelgeuse was shrinking faster than expected a few years ago. (June 10, 2009) Folks on Earth could be have a grandstand seat for the show 'sooner.' Again, by cosmic standards.

More:

• "Betelgeuse Braces for a Collision"
  Space Science, ESA (January 22, 2013)
• "A Brief History of the Microwave Oven"
  J. Carlton Gallawa (1996-2013)
• "Supernovas & Supernova Remnants"
  Chandra X-Ray Observatory, NASA

Related posts:

• Stars
  • "WR 104: Gamma Ray Bursts and a Musing Lemming"
    (January 4, 2013)
  • "Betelgeuse Blows in 2012? 'Don't Bet on It' "
    (January 22, 2011)
  • "Oh, Wow! Betelgeuse Has a Couple of Really Hot Spots"
    (January 13, 2010)
  • "Lemming Tracks: All Betelgeuse, All the Time"
    (June 10, 2009)
  • "Betelgeuse is Shrinking: Earth at Grandstand Distance from Supernova?"
    (June 10, 2009)
• Speculation
  
  • "Reason, Evidence, and Searching for Truth"
    A Catholic Citizen in America (February 3, 2013)
    Particularly
    • Another Week, Nine New Worlds
    • Kepler-47c
    • Life, the Universe, and Everything
  • "Another Step Closer to a Practical Warp Drive: Maybe"
    (November 30, 2012)
  • "Antimatter Rocket Motor: Physics, Straightforward; Engineering, Not So Much"
    (October 26, 2012)
  • "Time, the Universe, and Space Aliens"
    (April 20, 2012)
    Particularly
    • Space Aliens and the Universe
    • From Theoretical Physics to Working Spaceships
    • Possible, but Probable?
  • "Gods, Demons, and Used Spaceship Dealers"
    Drifting at the Edge of Time and Space (February 13, 2010)

Redefining Habitable Zones

" 'Habitable Zone' for Alien Planets, and Possibly Life, Redefined"
Clara Moskowitz, Space.com (January 29, 2013)

" One of the most important characteristics of an alien planet is whether or not it falls into what's called the habitable zone ­- a Goldilocks-like range of not-too-close, not-too-far distances from the parent star that might allow the planet to host life.

"Now scientists have redefined the boundaries of the habitable zone for alien planets, potentially kicking out some exoplanaets that were thought to fall within it, and maybe allowing a few that had been excluded to squeeze in...."

This isn't the final word in how far a planet needs to be from its star, for it to have an atmosphere, liquid water, and - maybe - life. It's probably a better estimate than the last one, since at that time scientists had solid information on exactly no planets outside the Solar system. Today, the count is in the hundreds. Make that thousands.

Scientists have a big enough sample now, to make a pretty good estimate for how many planets in this galaxy are about about the same size as Earth, and rocky. Unless Earth just happens to be in a very crowded corner of this galaxy, there are about 17,000,000,000 planets that are sort of like the inner four here: Mercury, Venus, Earth, and Mars.

Statistics, Earth, and Neighbors

If only one in four of those 17,000,000,000 planets have life, which is the local percentage: that's a whole lot of worlds with life. That's a big "if," though: and that brings the Lemming back to the revised guesstimate on where habitable zones are.

Good news, by the way: Earth is, according to the new estimate, still inside Sol's habitable zone. If it wasn't, the Lemming would wonder about how reliable this new-and-improved definition was. After all, we know there's life here on Earth.

If life got started somewhere besides Earth, and if it's close enough to 'life as we know it' for humans to recognize it as "life," and if this extraterrestrial life is close enough for humans to find in the near future: that's a lot of "ifs."

The Lemming would be excited if the Curiosity Mars rover found a wrecked spaceship that hadn't come from Earth: or a bit of plastic that couldn't have come from the rover. Even if the extraterrestrial wreck didn't have a speck of life on it, its presence would be proof that humanity had company: at one time.

But the first evidence of extraterrestrial life might be a little ecosystem supporting one-celled critters. That would be exciting, too.

The Lemming Philosophizes

The Lemming is fairly sure that the familiar 'science fiction' universe isn't what we're really living in. There's nothing wrong with telling a story about a galaxy teeming with non-human people - who all just happen to be almost exactly as smart as humans; with almost exactly the same interests, needs, and goals; and using almost exactly the same technology.

The universe could be like that, but probably isn't. If humanity was one of a few billion almost-exactly-like-human civilizations; all of which were within a few thousand years of each other in terms of technology - humanity would probably be selling souvenirs to space alien tourists.

It seems hard to remember how old the universe is. A million years ago, humans were learning how to use fire without killing themselves. But a million years is only a tiny fraction of the time that stars and planets have been spinning around this galaxy's core.

In the Lemming's opinion, when or if humanity meets other people - they won't be very much like humans. And that, again in the Lemming's opinion, is a good thing. Humans do a pretty good job of being human, there may be many other ways of being people, and we all could learn by comparing notes.

Even if there aren't any other people in this vast universe, just finding life elsewhere would let humanity learn a great deal. And this, again in the Lemming's opinion, is a good thing.

Related posts:

• In this blog
  • "Time, the Universe, and Space Aliens"
    (April 20, 2012)
    Particularly
    • Space Aliens and the Universe
  • "GJ 667Cc: Heavier than Earth, Maybe About as Warm"
    (February 6, 2012)
  • "The 'Christmas Planet:' Kepler-22b"
    (December 12, 2011)
  • "Beware Warmonger Imperialist Space Aliens!?"
    (January 11, 2011)
  • "Earth May Not Be a 'Class M' Planet"
    (December 5, 2009)
• In the Lemming's other blogs
  • "News, Good and Otherwise: and Billions of Worlds"
    A Catholic Citizen in America (January 11, 2013)
    Particularly
    • Planets Like Earth: Billions of Them
  • "Alpha Centauri, Freedom, and Me"
    A Catholic Citizen in America (October 19, 2012)
    Particularly
    • Science, Religion, and a Hairball
    • Alpha Centauri, Planets, and Life
  • "Science isn't a Four-Letter Word"
    A Catholic Citizen in America (January 29, 2012)
    Particularly
    • 1277 and All That
  • "Alien Life will Most Likely be - Alien"
    Drifting at the Edge of Time and Space (April 12, 2010)
    Particularly
    • 'Life as We Know It,' Class M Planets and All That
  • "Gods, Demons, and Used Spaceship Dealers"
    Drifting at the Edge of Time and Space (February 13, 2010)

WR 104: Gamma Ray Bursts and a Musing Lemming

"WR 104 Won't Kill Us After All"
Ian O'Neill, Universe Today (January 7, 2009)

"Early last year, concern was growing for a Wolf-Rayet star named WR 104 that appeared to be aiming right at Earth (see Looking Down the Barrel of A Gamma Ray Burst). A Wolf-Rayet star is a highly unstable star coming to the end of its life, possibly culminating in a powerful, planet-killing gamma-ray burst (GRB). GRBs are collimated beams of high energy gamma-rays, projected from the poles of a collapsing Wolf-Rayet star. It was little wonder that we were concerned when a dying Wolf-Rayet star was found to be pointing right at us! Today, at the AAS in Long Beach, one scientist working at the Keck Telescope has taken a keen interest in WR 104 and shared new findings that show our Solar System may not be bathed in deadly gamma-rays after all...."

As Marvin the Martian said, "Where's the kaboom? There was supposed to be an earth-shattering kaboom!"

Or, in this case, sizzle.

Technical Questions, Technical Answers, and the Lemming

"WR 104: Technical Questions"
Peter Tuthill, School of Physics, Sydney University, NSW 2006, Australia

" This page is for a more in-depth technical discussion of the risk posed by WR 104. There is jargon and techincal [!] stuff ahead, and I won't try to explain all the terms. Ask your local friendly Astronomer if in doubt.

"This discussion focusses [!] on the risk to earth from a potential future gamma ray burst (GRB) in WR 104. Note that this was not a big part of my scientific article published in Astrophysical Journal. The article only had a paragraph or two about this scenario. But for understandable reasons, the press and public have picked up on this aspect of the work. It is maybe a little more widely relevant than, say, 'radiative braking in colliding-wind systems' (which is discussed at length in the paper)...."


In another blog, the Lemming put information about WR 104 into a (fairly) short list:

• WR 104 is
  
  • About 8,000 light years away
    • 'Close' on a cosmic scale
  • A double star
  • 'Pointed' in our direction
    • Maybe
    • Or maybe not
• The stars will explode
  • Probably
  • Within the next 100,000 years
    • Or so
  • Twice
    • It's a double star
• The explosions will produce either
  • Two gamma ray bursts
  • One gamma ray burst
  • No gamma ray bursts
• The gamma ray burst(s), if any, will
  • Get deflected by magnetic fields
  • Be diffused by interstellar gas
  • Cause mass extinctions
    • Like the Ordovician mass extinction
    • Or not

Bottom line: in a hundred thousand years or so, one or both of the stars that humanity calls WR 104 will explode, probably.

One or both may or may not shoot a really intense clump of gamma rays in the general direction of Earth.

These gamma rays may get deflected by the Milky Way galaxy's magnetic fields; or they may get mushed up by the stuff between stars; or they may cause something like the Ordovician extinction event.

That Ordovician thing happened 440,000,000 or so years ago: 'Scientist Declares Doom' headlines notwithstanding, global disasters aren't all that common.

One Thing at a Time

The Lemming is, as this blog's name suggests, "apathetic." Maybe humanity will, a few hundred thousand years from now, face a cataclysmic catastrophe of cosmic scope. Then again, maybe not.

Come to think of it, by then humanity may have spread out a bit by then: which would raise the odds of at least one planetary system that's called "home" being in trouble.

The Lemming is content to let generations yet unborn decide whether to set up shielding, evacuate a few planetary systems, or maybe turn WR 104 so in shoots in another direction.

That last option might have unintended consequences. Someone else might be peeved, if humanity pointed WR 104 toward their home just before it exploded.

Related posts:

• "Oh, Wow! Betelgeuse Has a Couple of Really Hot Spots"
  (January 13, 2010)
• "Betelgeuse is Shrinking: Earth at Grandstand Distance from Supernova?"
  (June 10, 2009)
• "Betelgeuse Blows in 2012? 'Don't Bet on It' "
  (January 22, 2011)
• "Orion: Stars Under Construction and Otherwise"
  (January 9, 2011)
• "Move the Planet - or - Safety First"
  Drifting at the Edge of Time and Space (December 9, 2009)

Alpha Centauri B: New Planet

"Earth-Size Planet Closest to Our Solar System: By The Numbers"
Tariq Malik, SPACE.com (October 17, 2012)

"An alien planet discovered around a star in the Alpha Centauri system, the nearest to our own sun, has astronomers buzzing, and not just because it's the closest exoplanet to Earth ever seen.

"The newfound extrasolar planet Alpha Centauri Bb, it turns out, is not only the nearest alien world to Earth, it's also extremely Earthlike in size and mass. The planet is much too hot and too close to its parent star to support life, but its existence suggests the tantalizing possibility that there may be more planets waiting to be found in our neighboring star system.

"Here's a look at the numbers behind the newfound alien planet Alpha Centauri Bb:...

"3.6 million: The distance, in miles, at which the planet orbits its parent star Alpha Centauri B. This is much closer to the star than Mercury is to our sun. Earth is 93 million miles (150 million km) from the sun...."

Astronomers have found hundreds of exoplanets: planets orbiting other stars. What makes Alpha Centauri Bb stand out is it's mass, very nearly the same as Earth; and that it's very close.

"Close," that is, compared to most stars. Alpha Centauri A, B, and C are the nearest (known) stars: only four and a quarter light years away.

That's almost in Earth's back yard, compared to the size of our galaxy. Even Gliese 581, 20 light years away, is a close neighbor on a galactic scale.


(from Department of Physics, University of Oregon, used w/o permission)

On this scale, each pixel is well over 100 light years across. Sun and Gliese 581 are in the same pixel.

Too Hot for Life?

Alpha Centuari Bb "is much too hot and too close to its parent star to support life" is accurate, as far as it goes. The statement assumes that "life" is limited to "life as we know it," the sort of nucleic acid/protein (O) in water variety here on Earth. Maybe that's the only kind anywhere.

Then again, maybe "life" doesn't need to be the nucleic acid/protein in water mix that's comfortable on Earth. Life using fluorosilicone in fluorosilicone instead of our organic mix might be right at home on a nearly red-hot world.

Or maybe critters made of lipid in hydrogen live in the borderlands of our own planetary system. (Drifting at the Edge of Time and Space (April 12, 2010)

Alpha Centauri Bb: Really?

Some announcements of exoplanets are disputed, and occasionally turn out to be a misinterpretation of noise in the data. This time, it looks like Alpha Centauri Bb is very real: but time will tell.

• Exoplanets
  • "GJ 667Cc: Heavier than Earth, Maybe About as Warm"
    (February 6, 2012)
  • "Exoplanets: Over 700 Found to Date; Latest Batch of 18 are Jupiter-Size"
    (December 5, 2011)
  • "Gliese 581d: Rocky, Close (sort of), and Liquid Water (could be, maybe)"
    (May 18, 2011)
  • "GJ 1214b: Water in the Atmosphere; Close; and No Vacation Destination"
    (February 23, 2011)
  • "Gliese 581g, Alien Angst, and the Lemming"
    (October 4, 2010)
• Space aliens
  • "Alien Life will Most Likely be - Alien"
    Drifting at the Edge of Time and Space (April 12, 2010)
  • "Nuclear Weapons, Space Aliens, Conspiracy Theories, and Getting a Grip"
    (September 24, 2010)
  • "Gliese 581g, Space Aliens, and the Canals of Mars"
    (October 12, 2010)
  • "Space Aliens, the News, and Those Catholics"
    (November 11, 2009)
  • "Timing is Everything"
    Drifting at the Edge of Time and Space (October 7, 2009)

Of 40,000 Class M Stars, 18 Might Come (Sort of) Close

"Solar System 'Nemesis': Nearby Stars Could Pose Threat"
Mike Wall, Space.com (February 16, 2011)

"Astronomical detectives have assembled a stellar lineup, identifying a handful of nearby stars that may come close enough to disturb our solar system in the next billion years or so.

"Researchers calculated the orbits of 40,000 low-mass M-dwarf stars and found 18 that may come dangerously close to our cosmic neighborhood in the next billion years. While the chances of this actually happening are probably slim, researchers said, the results could be dramatic.

" 'The probability of an M dwarf running into the sun is essentially zero,' said study lead author John Bochanski of Pennsylvania State University, who presented the results in Seattle last month at the 217th meeting of the American Astronomical Society. 'But if one just came close, it could still cause comet showers.'..."

"Close" is a comparative term, of course. That chart, showing how close a few nearby stars may come over the next billion or so years, is marked off in kpc, or kiloparsecs. One parsec, or parallax second, is about 3.26 light years, or - a whacking long distance compared to driving down to the grocery.

The astronomers are quite calm about what they've found, since they almost certainly know just how big - and small - the numbers are that they reported. What happens when some movie producer hears what someone said about the "Nemesis" stars - well, there was that '2012' stuff. (November 16, 2009)

Related posts:

• "Solar System: In For Heavy Radiation, 'Soon' "
  (December 22, 2010)
• "Dinosaurs, Three Major Asteroid Impacts, and Massive Volcanic Eruptions"
  (August 29, 2010)
• "Clockwork Mass Extinctions, Cosmic Rays, and Cycles"
  (July 14, 2010)
• "Life on Other Worlds: Evolution, Orbits, and the Galactic Environment"
  (August 13, 2009)
• "The Sun as a Swinger? Cardiff U's Title is Better for Mass Extinction Article"
  (May 12, 2008)

Kepler 11: A Tightly-Packed Planetary System

"Tourist’s Guide to the New Alien Planet System Kepler-11"
Denise Chow, Space.com (February 2, 2011)

"The new discovery of six alien planets orbiting a sunlike star may be only a small part of the data released today (Feb. 2) from NASA's planet-hunting Kepler mission, but it is significant as the most tightly packed planetary arrangement around a single star yet discovered.

"The six planets orbiting Kepler-11 are all larger than Earth, with the largest ones comparable in size to Uranus and Neptune. As far as exoplanets go, these are relatively small worlds.

"Kepler-11 is located approximately 2,000 light-years from Earth. Astronomers used observations made by the Kepler spacecraft to detect the six planets that transit — pass in front of — the star....'

Fist of all, the Lemming - in a nit-picking mood - notes that we don't know (yet) if the Kepler-11 planets are "relatively small worlds" - "As far as exoplanets go." At this point, with fewer than a thousand expolanets - planets not orbiting Sol, our star - in the catalogs: We simply don't know what the 'typical' range of sizes is for planets in this galaxy.

Eventually, we'll have a large enough sample to be able to make educated guesses - but right now our detection methods work for large planets, and not so much for small ones like the one we live on. And that's almost another topic.

The Kepler 11 planetary system doesn't (as far as we can tell) have a planet that supports life. Or, rather, astronomers haven't spotted a planet there that's in the 'habitable zone' where water can exist on a planet's surface as a liquid.

Which may not be the only sort of place where life-as-we-know-it can exist. (January 26, 2011, March 24, 2010, May 12, 2010, March 5, 2009) Then there's life-as-we-don't-quite-know-it. (Drifting at the Edge of Time and Space ("April 12, 2010)

Back to the Kepler 11 system and its tightly-packed planets.

Five of the planets orbit Kepler 11 closer than Mercury does Sol. The sixth is closer than Venus is to our star.

Aside from the size of its planets' orbits, the Kepler 11 system is a bit like ours: all the planets orbit their star in roughly the same plane.

Studying them - and the hundreds of other expolanets - will help astronomers and cosmologists sort out the process(es) that produce planets. And, judging from what's happened in the last few thousand years of humanity's nosing about, raise new questions.

Frustrating? Not in the Lemming's opinion. "Exciting" is more like it.

Related posts:

• "Kepler-10b: Hot, Rocky, and the Smallest Exoplanet Yet"
  (January 11, 2011)
• "Posts About the Gliese 581 Planetary System: Including Gliese 581g"
  (October 14, 2010)
• "'More Than 100 Earth-Like Planets' Found? Well, No: Not Really"
  (July 24, 2010)
• "Planets Found Circling Other Stars: 429 So Far"
  (February 15, 2010)
• "Earth May Not Be a 'Class M' Planet"
  (December 5, 2009)

More in this blog:

• "A Serious Search for Other Worlds, Life, and - Maybe - Extra-Terrestrial Intelligence"

Betelgeuse Blows in 2012? 'Don't Bet on It'

"Dying Star Betelgeuse Won't Explode in 2012, Experts Say"
FoxNews.com (January 21, 2011)

"The super-giant red star Betelgeuse in Orion’s nebula is predicted to cataclysmically explode, and the impending supernova may even reach Earth -- someday.

"But will it happen by 2012, as recent news reports suggest? Probably not, experts told FoxNews.com. While the second biggest star in the universe is strangely losing mass -- and has already become a red giant, meaning it is destined to explode and become a supernova -- there's no reason to believe that it will happen anytime soon.

" 'The story is pretty "Hollywoody,"' said New Jersey Institute of Technology professor Philip R. Goode. In reality, the stars eventual explosion is inevitable, but no one knows when it will happen, he explained -- 2012 is pure conjecture...."

The article quotes Phil Plait, of Discovery News, who pointed out that Betelgeuse is too far away to do us much harm.

There's also a (very) short discussion of why Betelgeuse is about to blow: basically, it's running out of fuel.

The Lemming's written about Betelgeuse before. Also the various and sundry 'end-of-the-world' fads of the last thousand years or so.

Back to P. Plait: He's quoted, again, saying that Betelgeuse is expected to explode 'soon' - by cosmic standards. That's somewhere between right new and maybe 100,000 years from now.

The article ends with: "...Goode agreed. 'If you want to bet on it, it's better to try the lottery,' he said."

The 'Betelgeuse in 2012' thing reminded me of a recipe I made up for a post a few years back:

Recipe for fear and panic:

• Take one handful of journalists
• Add a pinch of facts
• Fold in one gallon of assumptions
• Shake vigorously
• Serve before facts rise to surface
  (October 10, 2007)

To be fair, the Lemming thinks there are some journalists who know how to use Google, and know the difference between a star and a planet. And that's another topic.

Sort-of-related posts:

• "Clockwork Mass Extinctions, Cosmic Rays, and Cycles"
  (July 14, 2010)
• "Killer Tomatoes: How Could I Have Missed This Classic?"
  (May 3, 2010)
• "Oh, Wow! Betelgeuse Has a Couple of Really Hot Spots"
  (January 13, 2010)
• "2012 and All That: The End of the World, from 500 to Now"
  (November 11, 2009)
• "Lemming Tracks: All Betelgeuse, All the Time"
  (June 10, 2009)

Big Star, Giant Planet, and Tides on the Star: Maybe

"Giant Alien Planet's Gravity May Make Star Pulsate"
Space.com (January 19, 2011)

"A huge, scorching-hot alien planet may be causing its parent star to inflate and deflate like a balloon, a new study suggests.

"The star WASP-33 (also known as HD 15082) pulsates in two directions - radially, like a balloon, and non-radially, like the tides in Earth's oceans. These pulsations might be caused by the powerful gravity of the star's planet, WASP-33b - a phenomenon never seen before in a planetary system, researchers said.

"WASP-33 is hotter than our sun, and about 50 percent more massive. It's found about 380 light-years away, in the constellation Andromeda. WASP-33b, the star's one known planet, was first detected in 2006 and confirmed in 2010.

"WASP-33b is about four times as massive as Jupiter, and it's so close to its host star that it completes an orbit every 1.2 days. Because of this extreme proximity, WASP-33b is perhaps the hottest alien planet known, with surface temperatures reaching 5,780 degrees Fahrenheit (3,193 degrees Celsius), according to a recent study...."

Right now, what scientists have found is are "...intriguing hints that the pulsations are tied to — and perhaps caused by — WASP-33b's motion around the star...."

Looks like another case where we now know a little more about how much we don't know.

Somewhat-related posts:

• "Our Sun's Sunspot Cycle Isn't All That Predictable"
  (June 16, 2010)
• "RCW 120: 'Impossible' Young Star Found by Herschel"
  (May 7, 2010)
• "Massive Stars: Magnetic Fields Involved in Their Formation"
  (November 23, 2009)
• "The Cat's Eye Nebula: Cool Photo"
  (April 24, 2009)

Orion: Stars Under Construction and Otherwise

"Great Hunter Orion Now Looms Large in the Night Sky"
Joe Rao, Space.com (January 7, 2011)

"If you look about due south around 9 p.m. your local time this week, you may see a familiar sight dominating our winter skies: the Great Hunter or Celestial Warrior, Orion, the most brilliant of the constellations and visible from every inhabited part of the Earth.

"This Orion constellation sky map shows what the famed star pattern will look like in the winter skies of the Northern Hemisphere, weather permitting.

"As is also the case with the mighty Hercules, the figure of Orion has been associated in virtually all ancient cultures with great national heroes, warriors or demigods. Yet, in contrast to Hercules, who was credited with a detailed series of exploits, Orion seems to us a vague and shadowy figure...."

The article has a pretty good star chart of Orion and surrounding constellations.

There's also a story about Orion, Hera, and a scorpion assassin. In tales from ancient Greece, one gets the idea that the Olympus crowd didn't appreciate bragging. Which is another topic.

Where was the Lemming? Orion. Constellation. Stars. Right. Mr. Rao gets into discussions of some of the real estate out in that direction. Like Rigel and Betelgeuse: both bright stars in our sky, but quite different in their current status.

I've written about Betelgeuse before, and put links at the end of this post. Bottom line about Betelgeuse: there's a good chance that it's going to explode in the not-too-distant future: "only a few million years," according to the article. When it blows, we'll be at an almost ideal viewing distance.

Then there's the Great Orion Nebula, where new stars are forming from a huge and (comparatively) dense cloud of dust and gas. The nebula is about 30 light years across: which makes it a naked-eye object at a distance of around 1,600 light years.

The Lemming likes the constellation Orion: partly because of the sights off in that direction; partly because it's one of the easier constellations to pick out.

Somewhat-related posts:

• "Massive Stars: Magnetic Fields Involved in Their Formation"
  (November 23, 2009)
• "Life's Sinister Origins: Comets?"
  (September 29, 2009)
• "Betelgeuse Shedding Mass Like There's No Tomorrow"
  (July 29, 2009)
• "Lemming Tracks: All Betelgeuse, All the Time"
  (June 10, 2009)
• "Betelgeuse is Shrinking: Faster Now Than Before"
  (June 10, 2009)

Gliese 581 System's Habitable Zone: New Numbers

"Alien Planet May Be in Habitable Zone After All"
Mike Wall, Space.com (December 20, 2010)

"The alien planet Gliese 581g has been getting a lot of attention recently as a possibly habitable world, but a case is building for its next-door neighbor as a good candidate for extraterrestrial life, too.

"Gliese 581d, another planet discovered around the star Gliese 581, may well lie in the 'habitable zone' of the star - that just-right distance range that can allow liquid water to exist — new atmospheric-modeling research suggests. The finding follows closely on the heels of a similar study, published earlier this year, that reached the same provisional conclusion. [Tour of the planets around star Gliese 581.]

" 'The fact that two models find conditions for liquid water could exist, that strongly implies that it is possible,' said the new study's lead author, Philip von Paris of the Institute for Planetary Research at the German Aerospace Center in Berlin. 'It doesn't seem impossible to have life there.'

"The Gliese 581 system: Worlds of possibilities

"Gliese 581 is a red dwarf located 20 light-years from Earth, just a stone's throw in the cosmic scheme of things. Astronomers have detected six planets orbiting the star...."

Actually, the number of planets circling Gliese 581 is under debate. Some scientists who didn't discover Gliese 581g say it's not there: and they may be right. Or, not.

The Lemming thinks that, at this point, it's safest to say that there 'about a half-dozen' planets in the Gliese 581 system, and leave it at that.

Mr. Wall discusses what a "habitable zone" is, and how scientists crunched the numbers to determine what the odds are that water and a breathable-by-something atmosphere could exist on one or more of the planets around Gliese 581.

Star Trek's 'class M planets' notwithstanding, places that wouldn't look much like southern California could support life. Like central Minnesota, for example.

There's even a possibility that Earth is about as small as a planet can be, and still maintain a breathable atmosphere. ("Earth May Not Be a 'Class M' Planet" (December 5, 2009)) And that's (almost) another topic.

That year-old post isn't all that far afield, though: the Gliese 581 planets found (so far) are more massive than Earth. But not by much, in some cases.

As for some balmy tropic world inhabited by beautiful space princesses? That's another topic. ("Beautiful Space Princesses, Almost Certainly Not: Flying Whales, Maybe," Drifting at the Edge of Time and Space (December 8, 2009))

Related posts:

• "Gliese 581g: Then Again, Maybe So"
  (October 14, 2010)
• "Gliese 581g? Maybe Not"
  (October 13, 2010)
• "Gliese 581g, Space Aliens, and the Canals of Mars"
  (October 12, 2010)
• "Gliese 581g, Alien Angst, and the Lemming"
  (October 4, 2010)
• "Gliese 581g: Life? Maybe"
  (October 2, 2010)

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More:

• "Posts About the Gliese 581 Planetary System: Including Gliese 581g"
• "A Serious Search for Other Worlds, Life, and - Maybe - Extra-Terrestrial Intelligence"

Twinkle, Twinkle - - - Like a Zircon in the Sky

"Distant Star Enveloped By Ingredients for Fake Diamonds "
Space.com (December 7, 2010)

"A faraway star sparkles with the largest amount of zirconium — the stuff fake diamonds are made from — ever seen, according to a new study.

"The star has about 10,000 times more zirconium than our sun, in a form never recorded by astronomers before, researchers said. The strange star also has far more than the usual amounts of other elements like strontium, germanium and yttrium, they added.

" 'The huge excess of zirconium was a complete surprise,' the study's lead author, Naslim Neelamkodan, from Northern Ireland's Armagh Observatory, said in a statement. 'We had no reason to think this star was more peculiar than any other faint blue star discovered so far.'

"The researchers estimate that the zirconium cloud layer on the star weighs about 4 billion tons, or 4,000 times the world's annual production of zirconium...."

The star's called LS IV-14 116, it's about 2,000 light-years away and too dim to see without a really good telescope. If you could see it, it'd be on or near the border between the constellations Capricorn and Aquarius.

And no: the Lemming does not think that the freakishly high concentration of zirconium on that star is evidence of space aliens. It'd make a good story though: Enterprising space aliens fiddling with a star's chemistry to produce billions of tons of zirconium - which they would use to mass-produce cubic zirconia jewelry, undercutting the galaxy's diamond trade and thereby crushing the De Beers-Illuminati conspiracy!

Oops. The Lemming got carried away.

Back to the real world and LS IV-14 116.

Apparently the star is of the sort called a helium-rich hot subdwarf, except that it's - different. As the article said:

"...They found evidence of various common elements, as expected. But less expected were the strong signals indicating the presence of zirconium, in an odd form that exists only at temperatures above 36,000 degrees Fahrenheit (20,000 degrees Celsius).

"This type of zirconium had never been found in an astronomical spectrum, according to researchers...."

So: LS IV-14 116 is really different: with a unique substance in its atmosphere. As the Lemming's written before: when observation matches pretty closely to what's predicted, that's satisfactory; when observation shows something unexpected, that's exciting. It's exciting because there's something new to be learned.

In this case, probably about stellar evolution.

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Old Data Recombined, Making New Hubble Photo

"Cosmic Pillars of Carina Nebula Dominate New Hubble View"
Space.com (September 17, 2010)

"A new photo from the Hubble Space Telescope shows huge pillars of hydrogen gas and dust in the Carina Nebula about 7,500 light-years from Earth.

"The pillars are about 1 light-year tall, scientists say. That's nearly 6 trillion miles (9.7 trillion km), more than 60,000 times greater than the distance from the Earth to the sun. And the structures aren't giants by Carina standards: some of the nebula's pillars are three times as big. [Photo of Carina Nebula pillars.]

"The columns, and the other odd shapes in the photo, are sculpted by violent stellar winds and radiation from the nebula's massive stars. The dense structures in the image may be nurseries, regions birthing new stars.

"The Hubble telescope's new image is a composite of observations taken in 2005 of the region's hydrogen light and new observations of the area's atomic oxygen content...."

So it's not exactly a "new" image - it's what researchers got by combining data from 2005.

It's still - impressive.

One thing that caught the Lemming's attention is that the gasses of the Carina Nebula act like fluids, at the titanic scale we're looking at. That's impressive, considering that nebulae like that are at pressures that would be a really good vacuum here at Earth's surface.

Finally, there's that 'happy face' in the photo, just to the left of center.

Life Around a Red Dwarf Star? Could be

"Red Dwarfs May Be Safe Havens For Life"
Space News, Discovery News (July 4, 2010)

"It's been 15 years since astronomers first discovered a planet beyond the solar system orbiting a normal star. We've found lots of unusual exoplanets since then, but nothing where we think life could exist.

"In two to three years NASA's Kepler space telescope will provide the statistical bedrock for estimating the number of Earth clones in the galaxy...."

"...The planet will orbit a nearby red dwarf star found in surveys taken within 100 light-years of Earth. Why? Because red dwarfs are much more numerous than sun-like stars and so provide many more targets. Because red dwarfs are dim, planets orbiting them will not be as swamped by starlight and so their light is easier to measure...."

Some of this I'd read before: like a planet that's close enough to a red dwarf to be habitable (by us) would likely be tidally locked, with one side always facing the star. Some I hadn't. Red dwarf stars go through a long period in which they have flares: big ones. Radiation from those flares would be really, really hard on living things on any planet close enough to have liquid water.

Unless there was a super-strength ozone layer. Which, maybe, there would be. Universidad Nacional Autónoma de México (UNAM)'s astrobiologist Antigona Segura ran numbers from a known red dwarf flare - and demonstrated that the UV radiation would strengthen the ozone layer of an Earth-like planet - assuming that one was there.

All of which is quite theoretical, until we find a roughly Earth-size planet in a stable orbit at the right distance from a star.

Which, at the rate planets are being found these days, may not be that far off.

---

Related posts, at

• "A Serious Search for Other Worlds, Life, and - Maybe - Extra-Terrestrial Intelligence"

Our Sun's Sunspot Cycle Isn't All That Predictable

"Sun's Strange Behavior Baffles Astronomers"
Space.com (June 14, 2010)

"The sun's temper ebbs and flows on what scientists had thought was a pretty predictable cycle, but lately our closest star has been acting up.

"Typically, a few stormy years would knock out a satellite or two and maybe trip a power grid on Earth. Then a few years of quiet, and then back to the bad behavior. But an extremely long stretch of low activity in recent years has scientists baffled and scrambling for better forecasting models.

"An expected minimum of solar activity, between 2008 and 2009, was unusually deep. And while the sun would normally ramp up activity by now, heading into its next cycle, the sun may be on the verge of a weak solar cycle instead, astronomers said at the 216th meeting of the American Astronomical Society in Miami last month...."

I don't know that our Sun's behavior is "strange" - but it isn't quite as regular just now as it has been for the last 100 years or so. Which shouldn't be too surprising, since that's a tiny fraction of the 4,500,000,000 or so years that the star has been around. (1/45,000,000, of course)

I suspect that what's being observed now won't seem all that "strange," after researchers have another 100 - or 1,000 - or 10,000 years of observations to study.

We've learned a great deal about how the universe works, since Nicolaus Copernicus and others jump-started contemporary astronomy. We're also learning a little more about how much we don't know: which keeps things interesting.

As I quoted last year:

" 'Your mistake is to think that the little regularities we have observed on one planet for a few hundred years are the real unbreakable laws....' "

Grace Ironwood, Chapter 17.4, "That Hideous Strength" C. S. Lewis (1946)

Related posts:

• "Early Earth Didn't Freeze: Why?!"
  (June 6, 2010)
• "Global Warming: on Pluto. And Mars"
  (December 14, 2009)
• ""Little Regularities" - A Thought for the Day"
  (September 23, 2009)

---

Related posts, at

• "Change, American Culture, Trilobites, Humanity's History, and the Big Picture"

Upsilon Andromedae, Tilted Orbits, and Habitable Worlds

"Weird Orbits of Alien Planets Could Affect Chances for Life"
Space.com (May 24, 2010)

"The ability of life to thrive on alien worlds may be impacted by the wild and weird orbits of giant neighboring planets, new studies suggest.

"The heftier worlds in other planetary systems could exert large forces on smaller worlds, pushing and pulling them into changing orbits. In some cases, these weird orbits could cause some extrasolar planets to fluctuate between being habitable and being inhospitable to life.

"These changing conditions of habitability could impact the search for life on other worlds and astronomers' theories on the formation of planetary systems like our own.

" 'There is this crazy zoo of planets out there that probably are habitable,' research team member Rory Barnes of the University of Washington said, 'but their properties are very different from Earth and they're different from Earth because of their eccentric neighbors.'..."


(from NASA, ESA, and B. McArthur (The Univ. of Texas at Austin, McDonald Observ.), via Space.com, used w/o permission)
"An artist's illustration that compares the solar system with the Upsilon Andromedae system. Astronomers have recently discovered that not all planets orbit the bright yellow-white star Upsilon Andromedae in the same plane, as the major planets in our solar system orbit the Sun. The orbits of two of the planets, c and d, are inclined by 30 degrees with respect to each other. Credit: NASA, ESA, and A. Feild (STScI) Science: NASA, ESA, and B. McArthur (The Univ. of Texas at Austin, McDonald Observ.)"

Until very recently, the only planetary system we could observe - or knew existed - was our Solar system: the planets, asteroids, and assorted things orbiting our sun, Sol. The planets, from Mercury out to Neptune, and the asteroids, all orbit in almost exactly the same plane. Even Pluto isn't that far out of the ecliptic, the plane of Earth's orbit.

Then, a decade or so back, astronomers developed ways to detect planets circling other stars. The number of known exoplanets, planets circling other stars, is over 400 and is still growing.

Three of them orbit Upsilon Andromedae. Upsilon Andromedae is quite a bit like our sun: It's about the same temperature, but younger and somewhat more massive. When the three planets were detected, a reasonable assumption was that they all orbited in the same plane.

They don't.

"...But, new findings from computer modeling indicate that the habitability of some exoplanets could vary, based on the orbits of giant planetary neighbors.

"The discovery of these so-called weird orbits will have important implications for existing theories of how multi-planet systems evolve. The findings also show that some violent events can happen to disrupt planets' orbits after a planetary system forms.

" 'The findings mean that future studies of exoplanetary systems will be more complicated,' said Barbara McArthur of The University of Texas at Austin, who was the lead researcher for one of the studies. 'Astronomers can no longer assume all planets orbit their parent star in a single plane.'..."

The odds are that the Upsilon Andromedae planets formed in a single plane - but that something happened after that to tilt the orbits of the outer two. That "something" could have been a fourth massive planet that got thrown out of the system in the process, Upsilon Andromedae's binary companion (it's a double star), or - well, something else.

The tilted orbits of Upsilon Andromedae's outer planets - and the very eccentric orbits of massive planets in other systems - means that ideas like "habitable planet" and "habitable zone" are probably much more complicated than we thought.

"...'The bigger issue here is that the habitable zone is very complicated,' Barnes said. 'Earth's climate is affected slightly over tens of thousands of years by the orbits of other planets in the solar system, but it is possible that in many exoplanetary systems the layout of the planets is very important to habitability.'..."

As often happens in the sciences, the more we know, the more we discover that we don't know. That certainly keeps things from getting boring.

---

Related posts, at

• "A Serious Search for Other Worlds, Life, and - Maybe - Extra-Terrestrial Intelligence"

RCW 120: 'Impossible' Young Star Found by Herschel

"Birth of 'Impossible' Star Seen by European Space Telescope"
Space.com (May 6, 2010)

"New cosmic observations from the European-built Herschel infrared space observatory have revealed previously hidden details of star form tucked away in distant galaxies. One snapshot reveals what researchers called an 'impossible' star caught in the act of forming.

"The new images show thousands of these galaxies and beautiful star-forming clouds draped across the Milky Way.

"These images were part of the presentation of the first results from Herschel, which was launch on May 14 of last year, today during a major scientific symposium held at the European Space Agency (ESA), which runs the observatory, in Noordwijk, Netherlands. These results challenge old ideas of star birth, and open new roads for future research...."

"'Impossible' star

"In a statement, European scientists said Herschel has discovered an 'impossible' star so massive it would dwarf our own sun, but they are perplexed as to how it came to be. Herschel found the embryonic star in the star-forming cloud RCW 120...."

Here's a look at RCW 120:

"This galactic bubble is known as RCW 120. It lies about 4300 light-years away and has been formed by a star at its center. The star is not visible at these infrared wavelengths but pushes on the surrounding dust and gas with nothing more than the power of its starlight. Credit: ESA/PACS/SPIRE/HOBYS Consortia"

Another Star is Forming: What's so 'Impossible' About It?

Here's the deal: astronomers, astrophysicists, and cosmologists have come a long way in the last half-century or so. They've got a pretty good set of data, and a quite good set of mathematical models to account for how the stars we see formed and are evolving.

According to those models, no star can start out with more than eight times the mass of our sun.

The star that's forming inside RCW 120 has eight to 10 solar masses: and is still growing.

It's not the first 'too massive' star found. What's special about RCW 120 is that astronomers caught it as it is forming. Massive stars like this don't last long, and are quite rare.

Spotting one so close, this early in its development, is a major find. And yes, 4,300 light years is "close" by cosmic - or even galactic - standards. We're practically on top of the thing.

Somewhere in the next few hundred thousand years, RCW 120 will become one of the biggest, brightest stars in this galaxy. And, if astronomers can keep getting grants for their research - or finding other ways of supporting their work - we'll be able to document the process.

Given how much prep time we've got, astronomers may be able to get observing facilities set up closer to the star. Impossible? Okay: but remember that the Herschel observatory is a robot in Earth orbit. When I was growing up, that was literally 'science fiction.'

'My Mirror is Bigger Than Your Mirror'

"...The diameter of Herschel's main mirror is four times larger than any other infrared space telescope and 1.5 times larger than the Hubble Space Telescope...."

When it comes to telescopes, sometimes bigger is better. Particularly is you're trying to collect as much electromagnetic radiation (infrared, visible light, ultraviolet, whatever) as possible.

Sort-of-Related Posts:

• "Dark Flow: This Universe on the Move?"
  (March 18, 2010)
• "Warp Speed Kills? Let's Say It's an Engineering Challenge"
  (March 11, 2010)
• "Second Smallest Exoplanet Found: HD 156668b (Caution! Geeky Content!)"
  (January 10, 2010)
• "Exploding Star: Not, I Think, a Jor El Moment, But Interesting"
  (January 5, 2010)
• "Gamma Ray Flare in Pegasus"
  (December 13, 2009)
• "NASA Institute for Advanced Concepts: Time to Re-Start?"
  (August 11, 2009)
• "Massive Stars: Magnetic Fields Involved in Their Formation"
  (November 23, 2009)
• "Warp Drive Might Not Be Stable: Physcisists Take Another look at Alcubierre's Work"
  (June 12, 2009)
• "Lemming Tracks: All Betelgeuse, All the Time"
  (June 10, 2009, last updated January 13, 2010)
• "Warp Drive: Yes, it May Be Possible; But Don't Hold Your Breath"
  (May 7, 2009)

A Star and a Planet; or Two Planets; or a Brown Dwarf and a Planet; or Something Else

"Possible Alien World Around Mini-Star Tests Definition of a Planet"
Space.com (April 8, 2010)

"A planet-like object has been found to be orbiting a cold, miniature star called a brown dwarf, calling into question just what it means to be a planet.

"Brown dwarfs are not quite massive enough to be full-fledged stars; they are not dense or hot enough in their cores to ignite nuclear fusion, the process that powers stars.

" 'Brown dwarfs are nature's "almost stars" - gassy bodies that aren't quite hot enough in their cores to fuse hydrogen,' said researcher Kim McLeod, an astronomer at Wellesley College in Wellesley, Mass.

"And the new discovery of an apparent planet orbiting one of these mini stars seems to blur the line even more between a planet and a brown dwarf.

"In this case, the 'star' weighs about 20 times the mass of Jupiter, but its planet weighs not too much less – about 5 to 10 times Jupiter's mass. ..."

I suppose we could call them platyplanets - since, like the platypus, they don't fit into our existing categories all that well. Somehow, I don't think that name will catch on.

Two - things - pretty close to the same mass (one's only a few times more massive than the other), neither one of which supports nuclear fission, could be called a double planet. But I suppose that's controversial, since there isn't a 'real' star nearby. And planets orbit stars.

The ones we were familiar with, anyway.

Notice: "were familiar with." This is an exciting time to be alive: what was presented as 'well known' in my youth now - isn't. And right now it seems to be the case that, the more we find out about stars and planets, the less we know for sure.

Like this pair. The smaller object apparently formed in less than 1,000,000 years. Which is a crazy-short time on the cosmic scale. Too short. Planets can't form that fast. Or, rather, (most) existing theories had the process requiring a whole lot more time.

I've written about this sort of thing before - it's good news when observed data back up an existing mathematical model. It's better news, I think, when what we observe doesn't. That means we may have a whole new set of possibilities to explore.

---

Related posts, at

• "A Serious Search for Other Worlds, Life, and - Maybe - Extra-Terrestrial Intelligence"

Planet of the Single Sun

"Double Sunsets May be Common, But Twin-Star Setups Still Mysterious "
Space.com (January 18, 2010)

"The Earth may orbit around a single star, but most stars like our sun are binaries — two stars orbiting each other as a pair. In fact there are many three-star triple systems, even going up perhaps as high as seven-star — or septuplet — systems.

"Although astronomers once thought these systems might not easily support planets, worlds with multiple sunsets might actually prove common.

"And now, powerful telescopes are beginning to resolve these systems to reveal how they work...."

The rest of the article gives a sort of snapshot of where cosmologists and astrophysicists are at, trying to figure out how stars and planets form - and coming up with models that match what's actually observed.

As for whether or not a double star can have a planet orbiting it: that's not something to speculate about any more.

So far, "...scientists have detected a planet estimated at 1.76 times as massive as Jupiter orbiting the primary star of the Gamma Cephei binary system roughly 45 light years away. When the stars in binary systems are close together, planets have been spotted in orbits that take them around both — such is the case with PSR B1620-26 b, which orbits a pulsar and white dwarf located roughly 12,400 light-years away and is the oldest known alien planet at roughly 12.7 billion years old...."

As for finding a place like Star Wars' Tatooine, a planet with life orbiting a double star, that'll take longer. We may decide it's easier to make one. Which, as I say so often, is another topic.

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Related posts, at

• "A Serious Search for Other Worlds, Life, and - Maybe - Extra-Terrestrial Intelligence"