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kottke.org posts about astronomy

Gliese 581g, we hardly knew ye

That habitable exoplanet discovery? Maybe not.

Astronomer Francesco Pepe of the Geneva Observatory in Switzerland, who spoke Oct. 11 at an International Astronomical Union symposium on planetary systems, reported a new analysis using only HARPS data, but adding an extra 60 data points to the observations published in 2008. He and his colleagues could find no trace of the planet.


Potential Earth-like exoplanet discovered

A team of scientists has discovered a potentially habitable planet located about 20 light years from Earth.

The paper reports the discovery of two new planets around the nearby red dwarf star Gliese 581. This brings the total number of known planets around this star to six, the most yet discovered in a planetary system other than our own solar system. Like our solar system, the planets around Gliese 581 have nearly circular orbits.

The most interesting of the two new planets is Gliese 581g, with a mass three to four times that of the Earth and an orbital period of just under 37 days. Its mass indicates that it is probably a rocky planet with a definite surface and that it has enough gravity to hold on to an atmosphere, according to Vogt.

Gliese 581, located 20 light years away from Earth in the constellation Libra, has a somewhat checkered history of habitable-planet claims. Two previously detected planets in the system lie at the edges of the habitable zone, one on the hot side (planet c) and one on the cold side (planet d). While some astronomers still think planet d may be habitable if it has a thick atmosphere with a strong greenhouse effect to warm it up, others are skeptical. The newly discovered planet g, however, lies right in the middle of the habitable zone.

Sam Arbesman’s prediction of May 2011 might have been too conservative. And 20 light years…that means we could send a signal there, and if someone of sufficient technological capability is there and listening, we could hear something back within our lifetime. Contact! (thx, jimray)


Helvetica! In! Space!

Back in July, Ben Terrett wrote a post about how many instances of the word “helvetica” set in unkerned 100 pt Helvetica it would take to go from the Earth to the Moon:

The distance to the moon is 385,000,000,000 mm. The size of an unkerned piece of normal cut Helvetica at 100pt is 136.23 mm. Therefore it would take 2,826,206,643.42 helveticas to get to the moon.

But let’s say you wanted to stretch one “helvetica” over the same distance…at what point size would you need to set it? The answer is 282.6 billion points. At that size, the “h” would be 44,600 miles tall, roughly 5.6 times as tall as the Earth. Here’s what that would look like:

Helvetica, from the Earth to the Moon

The Earth is on the left and that little speck on the right side is the Moon. Here’s a close-up of the Earth and the “h”:

Helvetica and the Earth

And if you wanted to put it yet another way, the Earth is set in 50.2 billion point type โ€” Helvetically speaking โ€” while the Moon is set in 13.7 billion point type. (thx, @brainpicker)


Total solar eclipse video

It’s not so much a video of a total solar eclipse (the recent one, as seen from Argentina on July 11) as a video of people watching a total solar eclipse.

The sound is key…the reaction is very much The Rapture/End Times/high on ecstasy. If I had a bucket list, seeing a total solar eclipse would be on it. (via bobulate)


Star on planet violence on the rise

A new Hubble discovery was announced today and it’s not for the faint of heart. At least, that is, if you care deeply about mysterious exoplanets 600 light years away.

WASP-12b is orbiting a sun-like yellow dwarf star 600 light-years away and it has such a tight orbit (of only 1.1 days) that it is being roasted to nearly 2,800 degrees Fahrenheit. This superheated state has caused the doomed exoplanet to puff up to nearly twice the size of Jupiter.

WASP-12b is in trouble and there’s no Willis/Affleck/Bay mission planned to save it. That said, it’s going to take about another 10 million years for WASP-12b to be totally eaten, so it has time to cross a few things off its bucket list.


Star on the run

Today’s wild space story is brought to us by Bad Astronomy:

We have a stellar cluster with thousands of times the Sun’s mass embedded in a nebula furiously cranking out newborn stars. A lot of them are near the physical upper limit of how big a star can get. The whole thing is only a couple of million years old, a fraction of the galaxy’s lifespan. One beefy star with 90 times the Sun’s mass got too close to some other stars, which summarily flung it out of the cluster at high speed, fast enough to cross the distance from the Earth to the Moon in an hour (it took Apollo three days). The star is barreling through the flotsam in that galaxy, its violent stellar wind carving out a bubble of gas that points right back to the scene of the crime, nearly 4 quadrillion kilometers and a million years behind it.

Click through to see the pictures and read a more thorough write up.
PS: 70% of the reason I linked to this is because of the title, “Rampaging cannonball star is rampaging.”


Pluto-related hate mail from children

The Natural History Museum got a lot of hate mail from children when they demoted Pluto from planet to a resident of the Kuiper Belt, including this one from a fellow named Will:

Pluto hate mail


Planet Styrofoam

The Kepler space telescope has found a planet with the density of Styrofoam.


Top 10 astronomy photos of 2009

One of the better lists out there: the top astronomy photos of the year. From the list, this is a more detailed view of the Martian landscape than we’re used to seeing:

Martian landscape

My personal favorite, the photos taken by the LRO of Apollo 11’s landing site, made the list as well.


Hubble goes deep

In 2004, the Hubble Space Telescope took an image called the Hubble Ultra Deep Field; basically astronomers pointed the Hubble toward an “empty” part of space and took a long-exposure shot in the visible spectrum. What they found were thousands of far away galaxies from early in the development of the universe. Now the Hubble has peered even deeper into the universe in near-infrared and captured this image:

Hubble IR Deep Field

Each one of those little specks is an entire galaxy, some only 600 million years old. Here’s a zoomed-in section:

Hubble IR Deep Field


Milky Way chromoscope

Chromoscope provides views of the Milky Way galaxy in x-ray, visible, microwave, and several other EM wavelengths. This is the view in far infrared:

Milky Way in far IR


Water on the Moon

NASA announced that it has found pretty hard evidence of significant amounts of water on the Moon.

“We are ecstatic,” said Anthony Colaprete, LCROSS project scientist and principal investigator at NASA’s Ames Research Center in Moffett Field, Calif. “Multiple lines of evidence show water was present in both the high angle vapor plume and the ejecta curtain created by the LCROSS Centaur impact. The concentration and distribution of water and other substances requires further analysis, but it is safe to say Cabeus holds water.”

I don’t have to tell you about the implications here. Just think of how much you could sell authentic Moon bottled water for.


The Hubble’s improved eyesight

Before and after photos from the Hubble telescope, which recently underwent spaceLASIK to extend the life and capabilities of the prolific telescope.

Hubble Before After


Astronomy Photographer of the Year winners

The Royal Observatory has announced the winners of its Astronomy Photographer of the Year contest.

Planet Trails

I had no idea that images this sharp and detailed could be taken with non-pro ground telescopes…particularly these shots of the Horsehead Nebula and the surface of the Moon. More winners listed here.

Update: Jonathan Crowe notes that the gear used to take these photos isn’t cheap.

The winner’s photo of the Horsehead Nebula (mpastro2001 also had a second photo in the top five) used a 12 1/2” Ritchey-Chretien telescope ($21,500) and an SBIG STL11000 camera ($7,195 and up) with an AO-L adaptive optics accessory ($1,795) on a Paramount ME mount ($14,500). Total cost for just the equipment mentioned here: $44,990.


The solar superstorm of 1859

A massive solar flare on September 1, 1859 “caused the most potent disruption of Earth’s ionosphere in recorded history”.

Within hours, telegraph wires in both the United States and Europe spontaneously shorted out, causing numerous fires, while the Northern Lights, solar-induced phenomena more closely associated with regions near Earth’s North Pole, were documented as far south as Rome, Havana and Hawaii, with similar effects at the South Pole.

(via the browser)


Hubble Ultra Deep Field in 3-D

Using redshift data, a 3-D animated view of the Hubble Ultra Deep Field was created.


Our three Suns

In early July, a photographer took a picture of what appears to be three Suns rising over Gdansk Bay in Poland.

Triple Sunrise

The photographer insists that the effect was not created by the camera and was visible to the naked eye. The early consensus in the forums is that the photo was taken through a double-paned window.


We Choose the Moon

We Choose the Moon is a site that tracks the activities of the Apollo 11 mission as it happened 40 years ago. Nice work. The transmissions from the spacecraft, CAPCOM, and the lunar lander are cleverly published to and pulled in from Twitter.

With all this 40th anniversary stuff, I’m having trouble getting my mind around that the first Moon landing is as far removed from the present as the low point of The Great Depression was from my birth (i.e. the Moon landing, culturally speaking, is Ollie’s Great Depression). See also timeline twins. (via jimray)


Sixty Symbols videos

From the folks who brought you The Periodic Table of Videos, Sixty Symbols is a series of videos on the symbols used in physics and astronomy. (via snarkmarket)


Apollo 11 mission on Twitter

The scamps at Nature are updating the ApolloPlus40 Twitter account as the Apollo 11 mission happened 40 years ago. (thx, matt)


More extrasolar planetary news

Oliver Morton fills us in on the current happenings in the search for planets outside of our solar system. A friend of his clued him in on a technique that could be used to not only discover planets but to determine if those planets show signs of supporting Earth-like life.

When they are passing in front of their stars, their atmospheres are backlit in a way that can make spectroscopic analysis of the different chemicals in their atmospheres comparatively easy: the wavelengths of light absorbed by the various chemicals will show up, in a tiny way, in the spectrum of the starlight. And this is what makes it possible to imagine looking at them for signs of life.

What scientists would look for are planets with unstable atmospheres, which James Lovelock said was an indication of life.

After the extragalactic planet post this morning, Sam Arbesman sent me a link to systemic, a blog dedicated to the search for extrasolar planets written by Greg Laughlin, one of the scientists involved in the effort. Here are two relevant posts. In Forward, Laughlin says we’re very close to finding a nearby Earth-like planet:

Detailed Monte-Carlo simulations indicate that there’s a 98% probability that TESS will locate a potentially habitable transiting terrestrial planet orbiting a red dwarf lying closer than 50 parsecs. When this planet is found, JWST (which will launch near the end of TESS’s two year mission) can take its spectrum and obtain resolved measurements of molecular absorption in the atmosphere.

In Too cheap to meter, Laughlin presents a formula for the land value of such a discovery that depends on how far away the planet is, the age of the star it orbits, and the star’s visual magnitude.

Applying the formula to an exact Earth-analog orbiting Alpha Cen B, the value is boosted to 6.4 billion dollars, which seems to be the right order of magnitude. And applying the formula to Earth (using the Sun’s apparent visual magnitude) one arrives at a figure close to 5 quadrillion dollars, which is roughly the economic value of Earth (~100x the Earth’s current yearly GDP)…


First extragalactic planet?

Scientists may have found the first planet located in another galaxy. The evidence is a little sparse but the search technique they’re using is solid.

The idea is to use gravitational microlensing, in which a distant source star is briefly magnified by the gravity of an object passing in front of it. This technique has already found several planets in our galaxy, out to distances of thousands of light years. Extending the method from thousands to millions of light years won’t be easy, says Philippe Jetzer of the University of Zurich in Switzerland, but it should be possible.


The Moon in HD

HD video of the Moon from 13 miles above the surface taken by Japan’s KAGUYA probe. The probe’s orbit has been decaying since it began circling the Moon and will crash on the surface at 18:30 GMT on June 10.


The search for a nearby second Earth

Using a Chilean telescope, astronomer Debra Fischer is leading a team searching for Earth-like planets around Alpha Centuri, our sun’s nearest stellar neighbor.

RV shifts are how the vast majority of extrasolar worlds have been discovered, but only because these planets, called “hot Jupiters,” are extremely massive and in hellishly close orbits around their stars. Their stellar wobbles are measurable in meters per second; seeing the much smaller centimeters-per-second wobble of an Earth twin is orders of magnitude more difficult. For the Alpha Centauri system, the feat is akin to detecting a bacterium orbiting a meter from a sand grain-from a distance of 10 kilometers. But by devoting hundreds of nights of telescope time to collecting hundreds of thousands of individual observations of just these two stars, Fischer believes she can eventually distill the faint RV signal of any Earth-like planets. It’s simply a matter of statistics and brute force. The planets wouldn’t reveal themselves as images in a telescope, but as steadily strengthening probabilistic peaks.


Stargazing

An excerpt from one of Galileo Galilei’s letters to Don Virginio Cesarini:

Long experience has taught me this about the status of mankind with regard to matters requiring thought: the less people know and understand about them, the more positively they attempt to argue concerning them, while on the other hand to know and understand a multitude of things renders men cautious in passing judgment upon anything new.

Want more Galileo? The Istituto e Museo di Storia della Scienza in Florence is loaning out their exhibit, Galileo, the Medici and the Age of Astronomy to The Franklin in Philadelphia. It features one of the last two telescopes belonging to the astronomer, as well as his notes, paintings, and other instruments, including the cylindrical sundial and Michelangelo’s compass.


Quadruple transit of Saturn

The Hubble Space Telescope captured four of Saturn’s moons crossing its face at the same time. (via cyn-c)


HD video by Hubble telescope

This HD video taken by the Hubble telescope of Ganymede going behind Jupiter looks completely computer generated and surreal.


Top Ten Astronomy Pictures of 2008

Bad Astronomy has its list of the top 10 astronomy pictures of 2008 up. It includes this video of the moon orbiting the earth, comprised of a series of photos taken by a reassigned space probe.

There has never been a generation of humans in all of history who could see such an event. If you ever get a little depressed, or lonely, or think like there’s nothing going on that’s interesting any more, think on that for a moment or two. A thousand generations of people could only imagine such a thing, but we can actually do it.

(thx, amos)


How the universe might kill us

The universe is trying to kill us, let us count the (ten) ways.

Start worrying in a few million years about a cosmic dust collision, when the sun hits the closest spiral arm of our galaxy. Take your chances with an exploding star. Or manage to escape these threats, and you just get an extra 10^35 years before all matter decays anyway.


Bringing Pluto back to the solar system

Meg bought Ollie this ball a couple of weeks ago. It’s got all the planets of the solar system on it, plus the Sun. But no Pluto. That’s right, it’s barely been two years since Pluto was demoted to dwarf planet status and the toy manufacturers have already made the adjustment.

It saddens me that Ollie has to grow up in a world where Pluto isn’t considered a planet, although I take comfort that his textbooks probably won’t be updated by the time he’s in school. In the meantime, I’ve Sharpied Pluto onto his ball.

Pluto, back where it belongs

One ball at a time people, that’s how we win.