Tag: science

New data suggests that the crash of two white dwarf stars caused the nearest supernovae in 25 years

11:03 am

New data has found that the crash of two white dwarf stars not only caused the nearest supernova in 25 years, but appear to be the prime cause for these types of supernovae.

The data also says that there are no white dwarf primary systems in the Milky Way that are candidates to go supernova in this way. Thus, we can all sleep easy tonight!

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The most distant supernova discovered so far.

10:43 am

The most distant supernova discovered so far.

SN Primo is the farthest Type Ia supernova whose distance has been confirmed through spectroscopic observations. The supernova was discovered as part of a three-year Hubble program to survey faraway Type Ia supernovae, enabling searches for this special class of stellar explosion at greater distances than previously possible. The remote supernovae will help astronomers determine whether the exploding stars remain dependable distance markers across vast distances of space in an epoch when the cosmos was only one-third its current age of 13.7 billion years.

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The National Radio Astronomy Observatory (NRAO) has renamed the thirty-one year old Very Large Array (VLA) after Karl Jansky, the man who invented radio astronomy.

10:16 pm

A fitting honor: The National Radio Astronomy Observatory (NRAO) has renamed the recently upgraded thirty-one year old Very Large Array (VLA) after Karl Jansky, the man who invented radio astronomy.

Karl Guthe Jansky joined Bell Telephone Laboratories in New Jersey in 1928, immediately after receiving his undergraduate degree in physics. He was assigned the task of studying radio waves that interfered with the recently-opened transatlantic radiotelephone service. After designing and building advanced, specialized equipment, he made observations over the entire year of 1932 that allowed him to identify thunderstorms as major sources of radio interference, along with a much weaker, unidentified radio source. Careful study of this “strange hiss-type static” led to the conclusion that the radio waves originated from beyond our Solar System, and indeed came from the center of our Milky Way Galaxy.

His discovery was reported on the front page of the New York Times on May 5, 1933, and published in professional journals. Jansky thus opened an entirely new “window” on the Universe. Astronomers previously had been confined to observing those wavelengths of light that our eyes can see. “This discovery was like suddenly being able to see green light for the first time when we could only see blue before,” said Lo.

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Studying the Moon by starlight

10:34 am

The Moon's south pole by starlight

In a paper published today in the Journal for Geophysical Research, Planets, the science team for Lunar Reconnaissance Orbiter describe how they have used starlight to peer into the permanently shadowed craters of the Moon’s north and south poles. Looking only during the lunar night, they measured the dim albedo of the Moon from reflected starlight. From this very weak signal they were able to cull two interesting facts about these very cold and very dark places.

  • The ground at the bottom of these craters is more porous than the surrounding unshadowed terrain.
  • There is evidence in the spectroscopy of 1 to 2% water frost in these craters.

» Read more

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Underground again today

7:30 am

glass plate

Posting will be light today, as I am joining University of Arizona PhD student Sarah Trube and several other Arizona cavers on a cave trip to collect water samples in a southern Arizona cave. This is in connection with research Sarah is doing to analyze the chemistry of cave dripwater and how it leads to the formation of cave speleothems. Moreover, she is tracking water flow and attempting to link it to climate and weather variations over time.

I noticed Sarah’s water collection equipment on my first Tucson-area cave trip back last January. In one case she had attached a tube to the bottom of a stalactite which fed the dripwater into a bottle. In another case she placed glass plates on top of stalagmites to allow the dripwater to drip onto the plate and then evaporate. Last month I joined her on one of her collection trips, where she gathered glass plates for later analysis in the lab. Though the plates had not been in cave more than a few months, you could easily see a thin layer of calcite deposit on their surface.

Below the fold is an image of Sarah gathering dripwater during an earlier trip.
» Read more

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A fitting memorial

3:13 pm

Greeley Haven

Opportunity has settled into its winter haven.

NASA’s Mars Exploration Rover Opportunity will spend the next few months during the coldest part of Martian winter at Greeley Haven, an outcrop of rock on Mars recently named informally to honor Ronald Greeley, Arizona State University Regents’ professor of planetary geology, who died October 27, 2011.

I met and interviewed Greeley a number of times in writing articles for magazines like Sky & Telescope and Astronomy. For years he was a central figure in the field of planetary geology, and his life effort is one of the prime reasons the United States has dominated this field for most of the past half century, with a fleet of planetary missions presently at Mercury, Mars, Jupiter, Saturn, and Pluto, with many more to come.

The article notes that the International Astronomical Union (IAU) has the job of naming objects in space, and could take years to honor Greeley. I say that if these scientists, the true explorers of Mars, want to name something for him, then they should go ahead, and future generations should honor that choice, regardless of what the IAU says.

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New research suggests that a body-snatching parasitic fly might be the culbrit in the decline of the honeybee population in the U.S.

1:21 pm

Alien on Earth: New research suggests that a body-snatching parasitic fly might be the culprit in the decline of the honeybee population in the U.S.

The parasitic fly lays eggs in a bee’s abdomen. Several days later, the parasitized bee bumbles out of the hives—often at night—on a solo mission to nowhere. These bees often fly toward light and wind up unable to control their own bodies. After a bee dies, as many as 13 fly larvae crawl out from the bee’s neck. The bees’ behavior seems similar to that of ants that are parasitized—and then decapitated from within—by other fly larvae from the Apocephalus genus.

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What is this stuff?

10:41 pm

What is this stuff?

The uncertainty of science: In this week’s release of images from Mars Reconnaissance Orbiter, the science team posted the image on the right and asked, “What is this stuff?”

Here’s a hypothetical geologic history that might explain this scene: layered sediments were deposited by water or airfall (including volcanic pyroclastics). A crudely polygonal patterned ground was created by stresses in the sediments, and groundwater followed the fractures and deposited minerals that cemented the sediments. This was followed by perhaps billions of years of erosion by the wind, leaving the cemented fractures as high-standing ridges.

Of course, this story is almost certainly incomplete if not totally wrong.

Click here to see the close-up subimage from which I cropped the image on the right.

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A family struggles to complete a Knoxville to Nashville trip using an electric car

7:58 pm

An exercise in absurdity: A family struggles to complete the 180 mile trip from Knoxville to Nashville using an electric car.

The Blink fast-charge station was on the blink. Efforts to use the two available plugs yielded nothing for Stephen Smith when he and his family arrived in Lebanon in their electric vehicle.

But all was not lost as the Smiths closed in on their destination – a brother’s house only 22 miles away in Antioch. With ten miles of available power left on their car, they could take advantage of a slower charger next to the other at the Blink station at Cracker Barrel. It took about an hour, but the boost gave enough energy for a total of 30 miles.

They also had to pay attention to whether the route was flat or hilly, as any hills significantly reduced their range of about 75 miles. In addition, they found that even that number was unreliable, and that often the maximum range the car could travel was far less.

Even the fast-charge station still needed about 30 minutes to charge up the car. Imagine having to wait 30 minutes every time you needed to fill up, and imagine having to do it every 70 miles.

There is a reason electric cars can’t compete with gasoline, and this journey illustrates it.

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The NASA shuttle simulator for training astronauts is going to at Texas A&M

9:15 am

The NASA shuttle simulator for training astronauts is going to Texas A&M.

Valasek said it won’t be a static display for viewing but a functional flight simulator. Visitors will be able to sit in the seats and cockpit and manually fly a simulated re-entry as the shuttle astronauts did. “When operational again, the SMS will be the centerpiece of many educational, outreach, and research activities for a long time to come,” Valasek said. “And it will be accessible. Until now, 355 astronauts have trained on the Shuttle Motion Simulator and flown on a space shuttle mission. Now the rest of us can experience at least a part of the excitement of space exploration, just the way the astronauts trained for it.”

The simulator will be used in aerospace engineering courses and accessible to all Texas A&M students, staff, and faculty. Spaceflight enthusiasts and fans of technology, whether affiliated with the university or not, will also be able to enjoy it.

Now, this is what an engineering school should be focused on, rather than the skin color of its students.

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Bigotry on campus

6:24 pm

The newly named “associate dean for equity and inclusion” at the College of Engineering at the University of California, Berkeley, is promising “disruptive progress” in his effort to increase minorities at the school.

The plan [pdf] includes more money for staffing and facilities for the “equity and inclusion” department, plus more money and power for student organizations. Sadly, this is money and facilities that will no longer be available for actual education or research.
» Read more

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A Sun-like Star with Three Sub-Neptune Exoplanets and Two Earth-size Candidates

8:38 am

Want to read the actual paper, “A Sun-like star with three sub-Neptune exoplanets and two Earth-size candidates,” describing the discovery announced yesterday of two Earth-sized planet? You can download it here.

The paper’s closing paragraph sums the discovery up nicely:

A striking feature of the Kepler-20 planetary system is the presence of Earth-size rocky planet candidates interspersed between volatile-rich sub-Neptunes at smaller and larger orbital semi-major axes, as also seen in Kepler candidate multi-planet systems. Assuming that both [Kepler-20e] and [Kepler-20f] are planets, the distribution of the Kepler-20 planets in orbital order is as follows: Kepler-20b (3.7 days, 1.9 Earth radii), [Kepler-20e] (6.1 days, 0.9 Earth radii), Kepler-20c (10.9 days, 3.1 Earth radii), [Kepler-20f] (19.6 days, 1.0 Earth radii), and Kepler-20d (77.6 days, 2.8 Earth radii). Given the radii and irradiation fluxes of the two Earth-size planet candidates, they would not retain gas envelopes. The first, second, and fourth planets have high densities indicative of solid planets, while the other two planets have low densities requiring significant volatile content. The volatile-rich third planet, Kepler-20c dominates the inner part of the Kepler-20 system, by holding much more mass than the other three inner planets put together. In the Solar System, the terrestrial planets, gas-giants, and ice giants are neatly segregated in regions with increasing distance from the sun. Planet formation theories were developed to retrodict these Solar System composition trends. In the Kepler-20 system, the locations of the low-density sub-Neptunes that are rich in water and/or gas, and the Earth-size planet candidates does not exhibit a clean ordering with orbital period, challenging the conventional planet formation paradigm. In situ assembly may form multi-planet systems with close-in hot-Neptunes and super-Earths, provided the initial protoplanetary disk contained massive amounts of solids (∼ 50–100 Earth masses) within 1AU of the star.

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