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Assorted Personal Notations, Essays, and Other Jottings

Posts Tagged ‘science

[OBSCURA] The Milky Way’s 19 black holes

Eric Betz’s D-Brief blog post “Prepare for an Explosion of Gravitational Wave Detections”, examining the exciting possibility of imminent gravitational wave observations giving us unprecedented insight into black holes, included this map of the Milky Way Galaxy’s known 19 black holes. This graphic, by Astronomy‘s Roen Kelly, originally featured in Richard Talcott’s February 2016 article “A guide to the black holes in our backyard”. There are surely many more than 19, but these are all we know for now. Perhaps LIGO will let us track down some more?

Written by Randy McDonald

April 13, 2016 at 10:00 am

[LINK] “Ancient Pluto May Have Had Lakes And Rivers Of Nitrogen”

Universe Today’s Evan Gough notes that ancient Pluto seems to have had a much warmer climate, allowing for flowing nitrogen lakes and rivers.

The New Horizons probe revealed the surface features of Pluto in rich detail when it reached the dwarf planet in July 2015. Some of the features look like snapshots of rivers and lakes that are locked firmly in place by Pluto’s frigid temperatures. But now scientists studying the data coming back from New Horizons think that those frozen lakes and rivers could once have been liquid nitrogen.

Pluto has turned out be a surprisingly active place. New Horizons has shown us what might be clouds in Pluto’s atmosphere, mountains that might be ice volcanoes, and cliffs made of methane ice that melt away into the plains. If there were oceans and rivers of liquid nitrogen on the surface of Pluto, that would fit in with our evolving understanding of Pluto as a much more active planet than we thought.

Richard Binzel, a New Horizons team member from MIT, thinks that lakes of liquid nitrogen could have existed some 800 or 900 million years ago. It all stems from Pluto’s axial tilt, which at 120 degrees is much more pronounced than Earth’s relatively mild 23 degree tilt. And computer modelling suggests that this tilt could have even been more extreme many millions of years ago.

The result of this extreme tilt is that much more of Pluto’s surface would have been exposed to sunlight. That may have warmed Pluto enough to allow liquid nitrogen to flow over the planet’s surface. These kinds of changes to a planet’s axial tilt, (and precession and eccentricity) affect a planet’s climate in what are called Milankovitch cycles. The same cycles are thought to have a similar effect on Earth’s climate, though not as extreme as on Pluto.

According to Binzel, Pluto could be somewhere in between its temperature extremes, meaning that if Pluto will ever be warm enough for liquid nitrogen again, it could be hundreds of millions of years from now. “Right now, Pluto is between two extreme climate states,” Binzel says.

Written by Randy McDonald

March 23, 2016 at 1:04 pm

[LINK] “Psychologists Throw Open The “File Drawer””

Discover‘s Neuroskeptic blogs about a team of psychologists who are starting to publish papers showing negative findings, to help overcome publication bias.

The ‘file drawer problem’ refers to the fact that in science, many results remain unpublished – especially negative ones. This is a problem because it produces publication bias.

Now, a group of Belgian psychology researchers have decided to make a stand. In a bold move against publication bias, they’ve thrown open their own file drawer. In the new paper, Anthony Lane and colleagues from the Université catholique de Louvain say that they’ve realized that over the years, “our publication portfolio has become less and less representative of our actual findings”. Therefore, they “decided to get these [unpublished] studies out of our drawer and encourage other laboratories to do the same.”

Lane et al.’s research focus is oxytocin, the much-discussed “love hormone”. Their lab has published a number of papers reporting that an intranasal spray of oxytocin alters human behaviour. But they now reveal that they also tried to publish numerous negative findings, yet these null results remain in the file drawer because they weren’t accepted for publication.

Is there a file drawer problem in intranasal oxytocin research? If this is the case, it may also be the case in our laboratory. This paper aims to answer that question, document the extent of the problem, and discuss its implications for intranasal oxytocin research. We present eight studies (including 13 dependent variables overall, assessed through 25 different paradigms) that were performed in our lab from 2009 until 2014 on a total of 453 subjects…

As we will demonstrate below, the results were too often not those expected. Only four studies (most often a part of them) of the eight were submitted for publication, yielding five articles (2, 8, 27, 34, 35). Of these five articles, only one (27) reports a null-finding. We submitted several studies yielding null-findings to different journals (from general interest in psychology to specialized in biological psychology and in psychoenodcrinology) but they were rejected time and time again.

Written by Randy McDonald

March 20, 2016 at 3:18 pm

[LINK] “18 Billion Solar Mass Black Hole Rotates At 1/3 Speed Of Light”

Damn. From Universe Today’s Bob King, a report about a massive fast-rotating black hole at the centre of a quasar.

Way up in the constellation Cancer there’s a 14th magnitude speck of light you can claim in a 10-inch or larger telescope. If you saw it, you might sniff at something so insignificant, yet it represents the final farewell of chewed up stars as their remains whirl down the throat of an 18 billion solar mass black hole, one of the most massive known in the universe.

Astronomers know the object as OJ 287, a quasar that lies 3.5 billion light years from Earth. Quasars or quasi-stellar objects light up the centers of many remote galaxies. If we could pull up for a closer look, we’d see a brilliant, flattened accretion disk composed of heated star-stuff spinning about the central black hole at extreme speeds.

As matter gets sucked down the hole, jets of hot plasma and energetic light shoot out perpendicular to the disk. And if we’re so privileged that one of those jet happens to point directly at us, we call the quasar a “blazar”. Variability of the light streaming from the heart of a blazar is so constant, the object practically flickers.

Written by Randy McDonald

March 18, 2016 at 2:44 pm

[BLOG] Some Wednesday links

  • The Broadside Blog’s Caitlin Kelly wonders why people read at all in the 21st century world.
  • D-Brief notes how chickens have been modified to have dinosaur-like legs.
  • Dangerous Minds shares 19th century photos taken of Native Americans in their traditional and ceremonial wear.
  • The Dragon’s Gaze links to a paper predicting exoplanets orbiting HD 202628 and HD 207129 based on gaps in the debris disks of those stars.
  • The Dragon’s Tales notes that the director-general of the ESA asked China to opt to contribute to the International Space Station.
  • Joe. My. God. notes that the lesbian subtext of Xena will be made explicit in the remake.
  • Language Log looks at odd names, in the Chinese world and in the wider world.
  • Marginal Revolution links to a paper speculating that future economic growth will be absorbed entirley by life extension.
  • pollotenchegg maps changing birth rates across Ukrainian regions from 1960 on.
  • Towleroad quotes lesbian comedian Joy Behar on her incredulity about Caitlyn Jenner’s professed politics.

[LINK] “An Ancient Volcanic Cataclysm Spun Mars Off Its Poles”

Universe Today’s Evan Gough looks at new research suggesting a catastrophic history for Mars.

According to a new research paper from Sylvain Bouley at the University of Paris-South, and his colleagues, it may have been a massive, ancient outpouring of molten rock that threw Mars off kilter and helped change Mars into what it is today.

The Tharsis region is an ancient lava complex on Mars that dates back to between 4.1 billion and 3.7 billion years ago. It’s located in Mars’ Western Hemisphere, right near the equator. It’s made up of three huge shield volcanoes—Arsia Mons, Pavonis Mons, and Ascraeus Mons. Collectively, they’re known as Tharsis Montes. (Olympus Mons, the largest volcano in the Solar System, is not a part of the Tharsis complex, though it is near it.)

Tharsis is over 5,000 km across and over 10 miles thick, making it the largest volcanic complex in the Solar System. That much mass positioned after Mars was already formed and had an established rotation would have been cataclysmic. Think what would happen to Earth if Australia rose up 10 miles.

The new paper, published on March 2nd, 2016, in the journal Nature, says that the position of the Tharsis complex would have initiated a True Polar Wander (TPW.) Basically, what this means is that Tharsis’ huge mass would have forced Mars to shift its rotation, so that the location of Tharsis became the new equator.

It was thought that the emergence of Tharsis made Martian rivers—which formed later—flow the direction they do. But the study from Bouley and his colleagues shows that Martian rivers and valleys formed first—or maybe concurrently—and that the Tharsis TPW deformed the planet later.

The authors of the study calculated where the Martian poles would have been prior to Tharsis, and looked for evidence of polar conditions at those locations. The location of this ancient north pole contains a lot of ice today, and the location of the ancient south polar region also shows evidence of water.

The Nature paper is here.

The Tharsis region is the largest volcanic complex on Mars and in the Solar System. Young lava flows cover its surface (from the Amazonian period, less than 3 billion years ago) but its growth started during the Noachian era (more than 3.7 billion years ago). Its position has induced a reorientation of the planet with respect to its spin axis (true polar wander, TPW), which is responsible for the present equatorial position of the volcanic province. It has been suggested that the Tharsis load on the lithosphere influenced the orientation of the Noachian/Early Hesperian (more than 3.5 billion years ago) valley networks and therefore that most of the topography of Tharsis was completed before fluvial incision. Here we calculate the rotational figure of Mars (that is, its equilibrium shape) and its surface topography before Tharsis formed, when the spin axis of the planet was controlled by the difference in elevation between the northern and southern hemispheres (hemispheric dichotomy). We show that the observed directions of valley networks are also consistent with topographic gradients in this configuration and thus do not require the presence of the Tharsis load. Furthermore, the distribution of the valleys along a small circle tilted with respect to the equator is found to correspond to a southern-hemisphere latitudinal band in the pre-TPW geographical frame. Preferential accumulation of ice or water in a south tropical band is predicted by climate model simulations of early Mars applied to the pre-TPW topography. A late growth of Tharsis, contemporaneous with valley incision, has several implications for the early geological history of Mars, including the existence of glacial environments near the locations of the pre-TPW poles of rotation, and a possible link between volcanic outgassing from Tharsis and the stability of liquid water at the surface of Mars.

Written by Randy McDonald

March 9, 2016 at 7:36 pm

[LINK] “Whooping cranes are pretty terrible parents. Are humans to blame?”

The Washington Post’s Karen Brulliard notes notes that a much-hyped program to help whooping crane populations recover has failed, as it turns out humans can’t teach the birds how to parent their young.

For 15 years, whooping crane chicks have been hand-raised by scientists wearing white whooping crane costumes in Maryland, shipped to Wisconsin and taught to migrate by other white-robed people, before they are led south to Florida by costumed volunteer pilots flying ultralight aircraft.

It was one of the most quirky, beloved and interventionist American conservation efforts, meant to build a migratory population of endangered whooping cranes in eastern North America without making them used to humans. This month, the final graduating class of six young birds was released — yes, by people in white costumes — at St. Marks National Wildlife Refuge in northern Florida.

The program is ending, largely because whooping cranes have turned out to be lousy parents.

“They can establish pairs, they know how to mate, they can copulate, and they know how to lay eggs,” said Peter J. Fasbender, a U.S. Fish and Wildlife Service field supervisor for Minnesota and Wisconsin. “They’re just incapable of parenting.”

In the past 11 years, the eastern population has grown to about 100 birds, but it has managed only to fledge 10 chicks. The culprit, government biologists think, is what made the program the fascination of legions of schoolchildren who followed it: the disguised people and the aircraft leading cranes. Though they never spoke to the birds and also directed them with crane puppets, Fish and Wildlife decided that humans were still too involved in teaching the cranes how to live. In January, the agency announced that this year’s would be the last ultralight-led migration.

Written by Randy McDonald

March 4, 2016 at 2:39 pm

Posted in Science

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