Tag: astronomy

Astronomers Say Milky Way Has Around 2 Billion “Earth Analog” Planets (That’s the Bad News)

By Patrick Morgan | March 30, 2011 1:35 pm

What’s the News: Based on early Kepler data, astronomers say that the Milky Way galaxy may house at least two billion Earth-like planets—one for every several dozen sun-like stars. As NASA researcher Joseph Catanzarite told Space.com, “With that large a number, there’s a good chance life and maybe even intelligent life might exist on some of those planets. And that’s just our galaxy alone — there are 50 billion other galaxies.” But while 2 billion sounds like a lot, it’s actually far below many scientists’ expectation; Catanzarite says his teams’ findings actually show that Earth-like planets are “relatively scarce.”

How the Heck:

  • Using mathematical models to plot the size and orbital distance for all the potential planets spotted during four months’ worth of Kepler data, astronomers extrapolated the data and calculated that 1.4 to 2.7% of the Milky Way’s sun-like stars may have an Earth analog.
  • Two percent of the Milky Way’s roughly one hundred billion sun-like stars means that “you have two billion Earth analog planets in the galaxy,” Catanzarite told National Geographic.

What’s the Context:

Not So Fast:

  • MIT astronomer Sara Seager says that the team “completely underestimates the frequency of Earths.” The calculations are based on only four months of Kepler data—too early to be making an accurate projection.
  • There’s also the fact that Kepler can only detect the size and orbital distance (and occasionally the masses) of planets, which doesn’t tell you whether life as we know it could actually live there; Venus, for example, would roughly like Earth to aliens peering at us from many light-years away, but because of its atmosphere’s runaway greenhouse effect, it’s way too hot to be habitable.

Next Up: The astronomers plan on calculating an even more accurate number once all of Kepler’s data is in.

Reference: Joseph Catanzarite and Michael Shao. “The Occurrence Rate of Earth Analog Planets Orbiting Sunlike Stars.” arXiv:1103.1443v1 Image: Kepler/NASA

CATEGORIZED UNDER: Space

Itty Bitty Galaxy Home to Gargantuan Supermassive Black Hole

By Andrew Moseman | January 11, 2011 3:35 pm

One of these things is not like the other: Astronomers have spotted a dwarf galaxy that spans just 3,000 light years across (as opposed to our Milky Way’s diameter of 100,000 light years), but hosts an outsize supermassive black hole for its puny size.

From DISCOVER blogger Phil Plait:

Some smaller galaxies have supermassive black holes as well, but in general these dwarf galaxies have some structure to them, with a well-defined core. Henize 2-10, as you can see, it a mess! It doesn’t have much overall structure, which is why it’s classified as an irregular galaxy. The thinking for big galaxies is that the black hole forms at the same time as the galaxy itself, and to regulate the growth of each other. When you look at lots of big galaxies, there’s a pretty clear overall correlation between the mass of the black hole and the galaxy around it.

So it’s pretty weird that Henize 2-10 has a supermassive black hole at all, but it turns out the hole is also about a million times the mass of the Sun — that’s pretty freakin’ big for such a tiny galaxy! That’s 1/4 the mass of our own black hole, in a galaxy that itself is far smaller than ours.

For more details about this weird galaxy, check out the rest of this post at Bad Astronomy. And for more galaxy-black hole weirdness, read last week’s 80beats post about whether mergers of galaxies truly cause supermassive black holes to become hyperactive.

Related Content:
80beats: Study: Hyperactive Black Holes Aren’t Caused by Galactic Smash-ups
80beats: LHC’s Lack of Black Holes Rules Out Some Versions of String Theory
80beats: Far-Off Quasar Could Be the Spark That Ignites a Galaxy
80beats: Researchers Spot an Ancient Starburst from the Universe’s Dark Ages

Image: Reines, et al., NRAO/AUI/NSF, NASA

CATEGORIZED UNDER: Space

Cassini Catches a Glimpse of an Enormous Storm on Saturn

By Andrew Moseman | December 28, 2010 9:48 am

A new sight appeared on Saturn earlier this month: A massive, swirling storm with a tail that cuts across the gas giant. Amateur astronomer Anthony Wesley, who was the first to spot the Earth-sized scar on Jupiter last summer, took the first pictures of this storm. And then on Christmas Eve the Cassini spacecraft beamed home its own ravishing images.

From Phil Plait:

The spacecraft took images of the planet on December 24th, returning — as usual — jaw-dropping pictures of Saturn showing the storm. This image, taken with a blue filter, shows the storm clearly. The main spot is huge, about 6,000 km (3600 miles) across — half the size of Earth! Including the tail streaming off to the right, the whole system is over 60,000 km (36,000 miles) long.

There’s an added bonus in these images: the shadow of the rings on the planet’s clouds is obvious, but the rings are nearly invisible! You can just make out the rings as a thin line going horizontally across Saturn in the first image. These pictures were snapped when Cassini was almost directly above the rings, which are so thin they vanish when seen edge-on. Actually, that works out well as otherwise they might interfere with the view of the storm in these shots.

For more details, check out the rest of Phil’s post at Bad Astronomy.

Related Content:
80beats: By Demolishing a Moon, Saturn May Have Created Its Rings
80beats: Mysterious Smash on Jupiter Leaves an Earth-Sized Scar
Bad Astronomy: Saturn rages from a billion kilometers away

Image: NASA

CATEGORIZED UNDER: Space

Slept Through the Lunar Eclipse? No Problem—Here's What It Looked Like

By Andrew Moseman | December 21, 2010 1:05 pm

It’s the chilly winter solstice and the eclipse of the moon happened in the wee hours of this morning, so plenty of people probably didn’t sacrifice sleep and stand out in the cold to watch the sky show. No worries—those who did stay up took pictures.



This eclipse was visible across much of Europe, the Americas and parts of Asia. And it was more unusual than most because it coincided with the winter solstice and today’s official start of winter. [NPR]

Such an astronomical alignment hasn’t happened in centuries, and most people alive today won’t be around for the next one: It doesn’t happen again until 2094. Those who braved the cold and had clear viewing skies got to enjoy hours of the eclipse, as the Earth’s shadow began to fall on our natural satellite during the 1 a.m. hour Eastern time.

The total eclipse began about 2:40 a.m. and lasted 72 minutes, until 3:52 a.m. The moon then continued moving through the Earth’s shadow, emerging completely sometime after 5 a.m. The winter solstice, which occurs later in the day, is the time when the sun reaches its lowest point in the northern sky. The Naval Observatory said this year’s solstice will be at 6:38 p.m. [Washington Post]

But why is the moon bathed in blood red light?
Read More

CATEGORIZED UNDER: Space

Did This Astronomer's Religion Cost Him a Job Opportunity?

By Andrew Moseman | December 20, 2010 12:05 pm

GaskellWhen I attended the University of Nebraska, Martin Gaskell was a professor of astronomy there. Shortly thereafter, in 2007, he was leading candidate to take a position as head of an observatory at the University of Kentucky. Now, Gaskell has a new title: plaintiff.

Gaskell argues that he was passed over for the Kentucky position because of his religious beliefs. The astronomer sued the university, and now a judge has ruled that Gaskell vs. University of Kentucky can go to trial in February.

Both sides agree that Dr. Gaskell, 57, was invited to the university, in Lexington, for a job interview. In his lawsuit, he says that at the end of the interview, Michael Cavagnero, the chairman of the physics and astronomy department, asked about his religious beliefs. “Cavagnero stated that he had personally researched Gaskell’s religious beliefs,” the lawsuit says. According to Dr. Gaskell, the chairman said Dr. Gaskell’s religious beliefs and his “expression of them would be a matter of concern” to the dean. [The New York Times]

The lead-up to the trial has turned up emails that are rather embarrassing to the university, particularly one by staff member Sally A. Shafer to Cavagnero.

“Clearly this man is complex and likely fascinating to talk with,” Ms. Shafer wrote, “but potentially evangelical. If we hire him, we should expect similar content to be posted on or directly linked from the department Web site.” [The New York Times]

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CATEGORIZED UNDER: Space

Coming Tonight to North America: A Total Lunar Eclipse

By Andrew Moseman | December 20, 2010 9:51 am

lunareclipseA week ago, sky-watchers were bundling up to take in the Geminid meteor shower. But tonight, there’s an even more powerful show coming to the sky. In North America, a total eclipse of the moon begins at about 1:30 a.m. Eastern (Tuesday morning).

From Phil Plait:

Lunar eclipses are cool, but slow. They’re not like solar eclipses which last a few minutes at most; the shadow of the Earth is quite large, and it takes the Moon a while to move through it (also unlike a solar eclipse, lunar eclipses are perfectly safe to watch with your eyes, with binoculars, or through a telescope without protection). Not only that, there are two parts to the shadow: the outer penumbra, which is very difficult to see when it falls on the Moon, and the much darker umbra, which is what really casts the Moon into the dark. In other words, things really gets started when the Moon moves into the umbra.

If it’s cloudy where you are, or you’re on the wrong side of the planet, never fear: you can still get a look because NASA is hosting a live chat and video feed of the eclipse! JPL has set up a Flickr page for people to post their pictures of the eclipse, too. If you Americans miss this eclipse, you’ll have to wait over three years before the next one, which occurs on April 14, 2014.

For more details, check out the rest of Phil’s post at Bad Astronomy.

Related Content:
80beats: Astronomers Display the Eclipse of a Star With Amazing Thermal Images
Bad Astronomy: Solar Eclipse, From Space!
Bad Astronomy: The July eclipse, from 12,000 meters up

Image: Anthony Ayiomamitis

CATEGORIZED UNDER: Space
MORE ABOUT: astronomy, eclipse, moon

Grab Your Winter Coat and Catch the Geminid Meteor Shower Tonight

By Andrew Moseman | December 13, 2010 9:41 am

GeminidAnother great night for stargazers has arrived as the annual Geminid meteor shower reaches its peak tonight (Monday) and into Tuesday morning.

Although many people consider it to be a poor cousin to August’s Perseid shower, the Geminids often put on a better show. This year, observers can expect to see upward of 100 “shooting stars” per hour — an average of nearly two per minute — under a dark sky. [Astronomy]

If clear skies prevail, it should be an ideal year for gazing at this shower—so named because the meteors appear to emanate from the constellation Gemini.

This year the Geminids are predicted to peak on Tuesday morning around 1100 GMT, more or less. That’s excellent timing for North America, especially out west. The moon that night is only a day past first quarter and sets around midnight or 1 am local time, depending on where you live. [New Scientist]

Unlike the Leonid and Perseid showers, which appear in the sky earlier each year and result from the Earth passing through the debris trail of a comet, the Geminds don’t have such a clear explanation. The meteors can be traced to an asteroid called Phaethon. Perhaps Phaethon is the iceless remainder of a former comet that has now lost its ice, but not everyone buys that hypothesis.

Indeed its spectrum links it to the large asteroid Pallas, 544km [338 miles] wide. Were Phaethon and other so-called Palladian asteroids blasted from Pallas in some ancient collision? And where does the dust in Phaethon’s orbit, our Geminid meteoroids, come from? One theory, backed up last year by observations of Phaethon as it passed through perihelion only 21 million km from the Sun, is that the Sun’s intense heat can cause Phaethon’s rocks to shatter, with the fragments able to escape Phaethon’s feeble gravitational pull to replenish the Geminids stream. [The Guardian]

Related Content:
80beats: Take a Look up at the Leonid Meteor Shower This Week
80beats: Perseid Meteor Shower: Where & When to Catch the Sky Show
80beats: Study: 20-Million-Year Meteor Shower Turned Earth Warm & Wet

Image: NASA

CATEGORIZED UNDER: Space

Super-Hot Super-Earth May Have an Atmosphere of Steam

By Andrew Moseman | December 1, 2010 1:35 pm

SteamyexoplanetFrom Phil Plait:

Last year, astronomers discovered a remarkable planet orbiting another star: it has a mass and radius that puts it in the “super-Earth” category — meaning it’s more like the Earth than a giant Jupiter-like planet. Today, it has been announced that astronomers have been able to analyze the atmosphere of the planet (the very first time this has ever been accomplished for a super-Earth), and what they found is astonishing: the air of the planet is either shrouded in thick haze, or it’s loaded with water vapor… in other words, steam!

Astronomers observed the planet when it passed in front of the star, analyzing the light very carefully. As starlight passes through the planet’s atmosphere, certain colors of it get absorbed, and these are like fingerprints that can be used to figure out the atmospheric composition. Most models predicted a heavy hydrogen content, but the observations indicate none is there! That means either there are thick layers of haze in the upper atmosphere of the planet, obscuring any hydrogen below them — much like Venus or Saturn’s moon Titan, blocking the view lower down — or there is a vast amount of water in the planet’s air. And at a temperature of 200° C, that water would be in the form of vapor. In other words, steam.

For the full scoop on GJ 1214b, located about 42 light years from here, check out Phil’s entire post at Bad Astronomy.

Related Content:
80beats: Found: An Exoplanet From Another Galaxy
80beats: Astronomers Predict a Bonanza of Earth-Sized Exoplanets
80beats: Um… That “Goldilocks” Exoplanet May Not Exist
Discoblog: So, How Long Would It Take to Travel to That Exciting New Exoplanet?
DISCOVER: How Long Until We Find a Second Earth?

Image: ESO

CATEGORIZED UNDER: Space

Take a Look up at the Leonid Meteor Shower This Week

By Andrew Moseman | November 16, 2010 4:49 pm

Leonids1833If you pull yourself out of bed before dawn tomorrow (Wednesday) or Thursday, take a look up at the sky. This week the Leonid meteor shower will streak across our skies.

The Leonids started out as tiny specks of dust and debris ejected by Comet 55P/Tempel-Tuttle during its countless voyages orbiting the Sun. As Earth passes through this stream of dust, the particles hit our atmosphere at about 158,000 mph (256,000 km/h), vaporizing due to air friction. This produces the streaks of light in the sky we call meteors. [Astronomy]

The shower lasts for about two weeks, reaching its apex over the next few nights.

Viewers under a dark sky can expect to see around 20 meteors per hour radiating from the constellation Leo the Lion. Unfortunately, a waxing gibbous Moon interferes with observations for much of the night. The best views will come after the Moon sets around 3 a.m. local time. [Astronomy]

While astronomers predict this year’s sky show will be tamer than last year’s, the Leonids have been known to strike the sky with a fury.

This spectacular 1833 Leonid meteor storm [seen above in a late-1800s engraving] made a deep and terrifying impression on the American people. According to newspaper reports almost everyone saw it, awakened either by the commotion in the streets or by the moving glare of fireballs shining into bedroom windows. This point of emanation of the meteors (called the “radiant”) was in the same place for all observers and remained so as the night wore on and the sky turned. Here was proof that the meteors were parallel to each other from somewhere outside of our atmosphere. [MSNBC]

Related Content:
Bad Astronomy: Leonids ROCK! (Check out the link to the amazing Mt. Hopkins video of a Leonid shower)
80beats: Study: 20-Million-Year Meteor Shower Turned Earth Warm & Wet
80beats: Found on a Martian Field: A Whomping Big Meteorite

Image: Wikimedia Commons

CATEGORIZED UNDER: Space

Danish Astronomer Tycho Brahe Gets a Postmortem, 400 Years Late

By Andrew Moseman | November 15, 2010 10:43 am

TychoGraveWe just won’t let Tycho Brahe be.

A colorful character and a father of modern astronomy, Brahe died in 1601 and was buried at Tyn Church near Prague’s Old Town Square. But the popular explanation for his expiration—a bladder infection—just doesn’t satisfy modern scientists seeking the truth about Tycho. So this week, Danish and Czech scientists (Brahe was Danish but died in Prague) got permission to exhume the long-dead stargazer to find evidence of his true cause of death.

His body has been exhumed before, in 1901. Tests on a sample of hair from his moustache, taken at that time, have been conducted as recently as the 1990s and indicated unusually high levels of mercury. Brahe was also an alchemist and some have suggested that he would have handled mercury and may have administered it to himself as medicine. Others have suggested he was poisoned. [BBC News]

Read More

CATEGORIZED UNDER: Health & Medicine, Space
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