Tag: astronomy

New data suggesting the presence of granite on Mars also suggests that the planet is more geologically complex than previously believed.

9:17 am

The uncertainty of science: New data suggesting the presence of granite on Mars also suggests that the planet is more geologically complex than previously believed.

In my years of science writing, I can’t count the number of times I’ve written the phrase “more complex than previously believed.” For some reason, modern scientists seem to always assume that things will be simple, with one straight-forward answer. From gamma ray bursts to supernovae to planetary formation to whatever, the first example found and the first theory developed from that first example has repeatedly been expected to explain everything.

But that’s not how things work. Instead, the closer scientists have looked, the more complex and interesting things have always become. Many different things can cause gamma ray bursts. Supernovae come in many types. Solar systems don’t have to resemble ours. Everything is always more complex than you first believe.

Scientists would get things wrong less often if they simply kept this thought in mind, at all times.

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Comet ISON brightens to just within naked eye visibility.

5:50 pm

Comet ISON brightens to just within naked eye visibility.

“[T]he little but intensely condensed, globular cluster-looking comet was a whopping magnitude 5.4 — two full magnitudes brighter than just 24 hours ago! This makes for a three magnitude total rise since my observation on Monday.” In just 72 hours, Comet ISON increased nearly 16 times in brightness.

Don’t get too excited. Magnitude 5.4 would make it comparable to one of the dimmer stars in the night sky, while the description above indicates it looks less like a comet and more like a blob.

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The number of candidate exoplanets found by Kepler has now risen to 3,500.

11:09 am

Worlds without end: The number of candidate exoplanets found by Kepler has now risen to 3,500.

According to this new analysis, researchers estimate about 70% of stars are host to at least one planet, making planets a common cosmic occurrence. There are now 1,750 candidates that are super-Earth-size or smaller, and 1,788 are Neptune-size or larger. Only 167 of the 3,538 candidates are confirmed to be planets, but Kepler has a good track record: the vast majority of these are probably real.

Two dozen of these candidates are in the habitable zone, ten of which are thought to be close to Earth-sized.

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The accumulated evidence from the Chelyabinsk meteorite now suggests the risk of large asteroid impacts might be ten times greater than previously estimated.

12:07 pm

The accumulated evidence from the Chelyabinsk meteorite now suggests the risk of large asteroid impacts might be ten times greater than previously estimated.

The Chelyabinsk asteroid had approached Earth from a region of the sky that is inaccessible to ground-based telescopes. In the 6 weeks before the impact, it would have been visible above the horizon only during the daytime, when the sky is too bright to see objects of its size, says Borovička.

“The residual impact risk — from asteroids with yet-unknown orbits — is shifting to small-sized objects,” says Peter Brown, a planetary scientist at the University of Western Ontario in London, Canada, and an author on the Nature papers.

Of the millions of estimated near-Earth asteroids 10–20 metres in diameter, only about 500 have been catalogued. Models suggest that an object the size of the Chelyabinsk asteroid hits Earth once every 150 years on average, Brown says. But the number of observed impacts exceeding 1 kiloton of TNT over the past 20 years alone hints at an actual impact risk that may be an order of magnitude larger than previously assumed,

The data also now suggests that the Chelyabinsk asteroid was twice as big as previously thought, and that it had an almost identical orbit to a much larger already known asteroid.

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For its next science mission the European Space Agency (ESA) has now decided to give first priority to an X-ray space telescope.

9:17 am

For its next science mission the European Space Agency (ESA) has now decided to give first priority to an X-ray space telescope.

They have demoted a space-based gravity wave detector to second place. As is typical for ESA, the pace here is quite slow, as both missions are now scheduled for launch in 2028 and 2034, decades away.

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Sunrise tomorrow on the East Coast will be interesting, as the sun will rise in the middle of a partial solar eclipse.

8:40 am

Sunrise tomorrow on the East Coast will be interesting, as the sun will rise in the middle of a partial solar eclipse.

Technically speaking, the partial eclipse could be visible as far inland as, say, Tennessee. Sky & Telescope projects that 57 percent of the sun’s diameter could be covered over at sunrise in Boston, 48 percent in New York, 44 percent in Philadelphia, 35 percent in Washington, and 36 percent in Miami. But you’d have to have a clear view of a flat horizon — and no matter where you are on the East Coast, the partial eclipse will be over within an hour after sunrise.

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The first Earth-sized exoplanet, just discovered, makes no sense to scientists.

1:14 pm

The first Earth-sized exoplanet, just discovered, makes no sense to scientists.

Kepler-78b is a planet that shouldn’t exist. This scorching lava world circles its star every eight and a half hours at a distance of less than one million miles – one of the tightest known orbits. According to current theories of planet formation, it couldn’t have formed so close to its star, nor could it have moved there. “This planet is a complete mystery,” says astronomer David Latham of the Harvard-Smithsonian Center for Astrophysics (CfA). “We don’t know how it formed or how it got to where it is today. What we do know is that it’s not going to last forever.”

The planet itself is only 20 percent larger than the Earth, with a comparable density that suggests its composition is similar as well.

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Europe turns off Planck

8:32 am

Europe turns off Planck.

Planck operated four-and-a-half years, three times longer than originally planned. Launched in May 2009 on an Ariane 5 rocket shared with ESA’s Herschel telescope, Planck measured the cosmic fingerprint of the Big Bang, detecting subtle variations in background light originating 380,000 years after the genesis of the universe.

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A remotely operated Russian telescope, located in New Mexico, on Wednesday discovered a kilometer wide Near Earth asteroid.

7:09 pm

Boom! A remotely operated Russian telescope, located in New Mexico, on Wednesday discovered a kilometer wide Near Earth asteroid.

The asteroid, believed to be the 704th largest with an orbit that comes relatively near Earth, does not pose a danger of crashing into our planet, said the head of the observatory that made the discovery. “It’s a big asteroid, but it poses no danger for us,” Leonid Elenin, who lives in the Moscow Region, told RIA Novosti on Friday.

Finding a new asteroid like this illustrates that there might be other such large objects out there undiscovered. Also cool is how the Russians discovered it, using equipment in the United States!

Posted from Midland, Texas, the center of the world for the American oil industry.

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Astronomers have found evidence of the remains of an exoplanet that they think was once wet and rocky.

6:12 pm

Astronomers have found evidence of the remains of an exoplanet that they think was once wet and rocky.

Using observations obtained with the Hubble Space Telescope and the large telescopes of the W. M. Keck Observatory , they found an excess of oxygen – a chemical signature that indicates that the debris had once been part of a bigger body originally composed of 26 per cent water by mass. By contrast, only approximately 0.023 per cent of the Earth’s mass is water.

From what I can gather, the actual data here is somewhat skimpy, requring a lot of assumptions for the scientists to come to this conclusion. Nonetheless, the data is interesting and very tantalizing.

Posted from Memphis, Tennessee.

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Is a natural rain of diamonds occurring on Jupiter and Saturn? Two scientists say yes!

5:07 am

Is a natural rain of diamonds occurring on Jupiter and Saturn? Two scientists say yes!

In their scenario, lightning zaps molecules of methane in the upper atmospheres of Saturn and Jupiter, liberating carbon atoms. These atoms then stick onto each other, forming larger particles of carbon soot, which the Cassini spacecraft may have spotted in dark storm clouds on Saturn3. As the soot particles slowly float down through ever-denser layers of gaseous and liquid hydrogen towards the planets’ rocky cores, they experience ever greater pressures and temperatures. The soot is compressed into graphite, and then into solid diamonds before reaching a temperature of about 8,000 °C, when the diamond melts, forming liquid diamond raindrops, they say. Inside Saturn, the conditions are right for diamond ‘hail’ to form, beginning at a depth of about 6,000 kilometres into the atmosphere and extending for another 30,000 km below that, says Baines. He estimates that Saturn may harbour about 10 million tonnes of diamond produced this way, with most of it made up of rocks no bigger than a millimetre and perhaps some chunks spanning 10 centimeters.

But don’t invest your money yet in a diamond gathering expedition. This is only a theory, which many scientists dispute.

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The weather on an exoplanet: Cloudy and clear.

3:09 pm

The weather on an exoplanet: Cloudy and clear.

Astronomers using data from NASA’s Kepler and Spitzer space telescopes have created the first cloud map of a planet beyond our solar system, a sizzling, Jupiter-like world known as Kepler-7b. The planet is marked by high clouds in the west and clear skies in the east. Previous studies from Spitzer have resulted in temperature maps of planets orbiting other stars, but this is the first look at cloud structures on a distant world.

This result is cool, but no one should take it too seriously. They have detected evidence of that to the scientists “suggest” clouds, but no one really knows.

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Comet ISON has now brightened to 11th magnitude as it approaches its flyby of Mars.

9:41 am

Comet ISON has now brightened to 11th magnitude as it approaches its flyby of Mars.

The story above is hopeful the comet will put on a show in November, but I am increasingly doubtful. To be even visible to the naked eye it must brighten to 6th magnitude, and it appears to be brightening far slower than expected.

Posted as we drive through El Paso, Texas.

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Linking mass extinctions to the Sun’s journey in the Milky Way

12:53 pm

The Sun's orbit in the Milky Way

In a paper published today on the Los Alamos astro-ph preprint service, astronomers propose that as many as eleven past extinction events can be linked to the Sun’s passage through the spiral arms of the Milky Way. (You can download the paper here [pdf].)

A correlation was found between the times at which the Sun crosses the spiral arms and six known mass extinction events. Furthermore, we identify five additional historical mass extinction events that might be explained by the motion of the Sun around our Galaxy. These five additional significant drops in marine genera that we find include significant reductions in diversity at 415, 322, 300, 145 and 33 Myr ago. Our simulations indicate that the Sun has spent ~60% of its time passing through our Galaxy’s various spiral arms.

The figure on the right, from their paper, shows the Sun’s orbit in red over the last half billion years. The Sun’s present position is indicated by the yellow spot, and the eleven extinctions are indicated by the circles.

There are obviously a great deal of uncertainties in this conclusion. Most significantly, the shape and history of the Milky Way remains very much in doubt, especially since we reside within it and cannot really get a good look at it. Though in recent years astronomers have assembled a reasonable image of the galaxy’s shape — a barred spiral with two major arms and several minor ones — this picture includes many assumptions that could very easily be wrong.

Nonetheless, the paper’s conclusions are interesting.
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