ريتشارد دوكنز's Blog, page 616

Ghosts Of Milky Way’s Past Revealed By Star Cluster

Space





Photo credit:

The globular cluster E 3 (center). by DSS/STScI/UDS/CNRS

A surprising fact about galactic astronomy is that we know more about other galaxies than our own. The Solar System is not in a great place to learn all there is to know about the Milky Way. The origin of our galaxy is still very mysterious, but we might have found a way to learn more about it.

The Jellyfish Nebula’s Supernova Origin Has Been Found

Space





Photo credit:

X-ray image of a pulsar within the Jellyfish Nebula. NASA/Chandra/JPL

There’s no smoke without a fire, and there’s no supernova remnant without some evidence of a past supernova explosion. The Jellyfish Nebula, also known as IC 443, is a supernova remnant that has so far remained without a culprit, but scientists have finally observed where the nebula started from.

Rising Sea Levels Shown To Slow Down Earth’s Rotation

Environment





Photo credit:

The Earth's rotation has slowed over the last few thousands years . Rob Byron/Shutterstock

With global temperatures increasing at a truly unprecedented rate, glaciers and ice sheets are melting, causing sea levels to begin to swallow up cities and islands across the world. A new study published today in Science Advances confirms that changing sea levels also affect the rotation of the Earth. By quantifying how potent this effect is, these researchers have possibly solved a longstanding conundrum called “Munk’s enigma.”

Eighty children get chickenpox at Brunswick North West Primary, a school that calls for ‘tolerance’ of vaccine dodgers

One in four of the children who attend a Brunswick school that calls for tolerance for vaccine dodgers has contracted chickenpox.

At least 80 of the 320 pupils at Brunswick North West Primary in Melbourne’s north have become ill with the disease in the past fortnight.

It is understood the illness spread through grade 6, before making its way through the lower levels to grade 2.

The Department of Health was first notified about the chickenpox cases on November 26.

“There are no firm figures on the number of students who have contracted the illness since then, but we’ve been advised that over the period there has been an absentee rate of about 25 per cent on any given day,” a department spokesman said.

The school has a lower immunisation rate than the state and national averages.

In the May newsletter, the school’s principal Trevor Bowen said 73.2 per cent of students were immunised, compared with 92 per cent within the local postcode.

In Victoria, the rate is 90.4 per cent, the newsletter says.

The school has previously asked parents to be tolerant of those with differing opinions on immunisation and there was still evidence of tension on Thursday between parents who did and those did not vaccinate their children.

Parent Sara McKenzie vaccinated her son Wesley, who is in grade one, but that didn’t stop him getting chickenpox.

She admits she was shocked that the rates of immunisation were so low at the school.

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The first plasma: the Wendelstein 7-X fusion device is now in operation

On 10th December 2015 the first helium plasma was produced in the Wendelstein 7-X fusion device at the Max Planck Institute for Plasma Physics (IPP) in Greifswald. After more than a year of technical preparations and tests, experimental operation has now commenced according to plan. Wendelstein 7-X, the world’s largest stellarator-type fusion device, will investigate the suitability of this type of device for a power station.

Following nine years of construction work and more than a million assembly hours, the main assembly of the Wendelstein 7-X was completed in April 2014. The operational preparations have been under way ever since. Each technical system was tested in turn, the vacuum in the vessels, the cooling system, the superconducting coils and the magnetic field they produce, the control system, as well as the heating devices and measuring instruments. On 10th December, the day had arrived: the operating team in the control room started up the magnetic field and initiated the computer-operated experiment control system. It fed around one milligram of helium gas into the evacuated plasma vessel, switched on the microwave heating for a short 1,3 megawatt pulse – and the first plasma could be observed by the installed cameras and measuring devices. “We’re starting with a plasma produced from the noble gas helium. We’re not changing over to the actual investigation object, a hydrogen plasma, until next year,” explains project leader Professor Thomas Klinger: “This is because it’s easier to achieve the plasma state with helium. In addition, we can clean the surface of the plasma vessel with helium plasmas.”

The first plasma in the machine had a duration of one tenth of a second and achieved a temperature of around one million degrees. “We’re very satisfied”, concludes Dr. Hans-Stephan Bosch, whose division is responsible for the operation of the Wendelstein 7-X, at the end of the first day of experimentation. “Everything went according to plan.” The next task will be to extend the duration of the plasma discharges and to investigate the best method of producing and heating helium plasmas using microwaves. After a break for New Year, confinement studies will continue in January, which will prepare the way for producing the first plasma from hydrogen.

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Astronomers Skeptical Over “Planet X” Claims

For decades, astronomers have searched for a possible “Planet X” in the far outer reaches of our solar system, speculating that something big and dark may be lurking out there, its gravitational influence occasionally stirring up trouble in the orbits of the objects that we do see. There are major incentives to look: When astronomers sought a Planet X beyond Uranus in 1846, they discovered Neptune; when they looked for one beyond Neptune in 1930, they found Pluto. Since then, the search for a Planet X beyond Pluto has almost been too successful—astronomers have found so many new and Pluto-like “trans-Neptunian objects” (TNOs), that it became more sensible to demote Pluto from planethood rather than swell the solar system’s planetary population into the hundreds. After all, even the largest of the newfound TNOs were just about Pluto’s size—astronomers knew of nothing out there worthy of the “Planet X” name.

That is, perhaps, until now. On December 8, researchers from Sweden and Mexico quietly submitted two papers to the prestigious journal Astronomy and Astrophysics, announcing their discovery of not one but two possible Planet X candidates. The quiet did not last for long. Even though neither paper has yet been accepted for peer-review and publication, the researchers uploaded both to the arXiv, a public online repository for pre-print papers, where they appeared last night. Today, as claims of newfound planets in our solar system reverberate around the world in news stories and blog posts, other astronomers are reviewing the papers and reacting mostly with skepticism. The ensuing discussions between experts in public forums like Twitter and Facebook offer a rare, real-time glimpse of the sometimes-messy scientific process as it unfolds.

“Normally I prefer to only upload accepted papers,” says Wouter Vlemmings, an astronomer at Chalmers University of Technology in Onsala, Sweden and co-author on both studies. “This time however, we had exhausted our ideas … With the arXiv upload we specifically wanted to reach the community that could tell us if we overlooked something, in which case we fully intend to withdraw the papers… What I personally did not count on was the impact it has had outside the astronomy community.”

One of the candidates, nicknamed “Gna” (after a fast-moving “Nordic messenger goddess,” Vlemmings says) showed up in the sky next to the star W Aquilae, while the other, as-yet-unnamed, appeared adjacent to our nearest neighboring star system Alpha Centauri. Astronomers detected both objects using the Atacama Large Millimeter/submillimeter Array (ALMA), a massive group of radio dishes perched in the high desert of the Chilean Andes, and thought at first that the bodies were faint glows from far-distant background galaxies. But in separate pairs of snapshots taken over a period of months, both objects seemed to move swiftly against the “fixed” background stars, suggesting a relatively close cosmic proximity to our solar system. Considerable uncertainty exists about the properties of both objects, since each was observed only twice, and bodies with a wide range of sizes, compositions and distances from us could explain the measured brightness.

Gna, the researchers say, is quite likely to be something like a 200-kilometer-wide asteroid floating between Saturn and Uranus, but it could also be a free-floating Neptune-sized planet drifting a hundred times farther out, or a failed star—a Jupiter-sized brown dwarf—passing by in nearby interstellar space. Similarly, the object seen in the direction of Alpha Centauri could conceivably be a nearby brown dwarf, a super-Earth midway in size between our planet and Neptune some six times farther out than Pluto, or an impressively-sized hunk of ice much, much closer in.

Alternatively, both objects could be illusory, random blips of noise echoing through the world’s most complex and ambitious array of radio telescopes. According to Scott Sheppard, a planetary scientist at the Carnegie Institution for Science in Baltimore involved with surveys of the outer solar system, the fact that only two observations apiece underpin both discovery claims makes them hard to swallow. “Anything could create two random detections, and you can always fit a straight line through any two points,” Sheppard says. Demonstrating that either object was real, he says, would likely require a third detection, one that shows the object’s clear, linear movement at a consistent speed.

What these objects are, and whether they exist at all, are open questions.  What is certain, however, is that earlier searches have placed limits on the possibilities for any Planet X. An all-sky search by NASA’s Wide-field Infrared Survey Telescope (WISE) previously found no signs of any additional planets in our solar system, ruling out anything Jupiter-sized within about three trillion kilometers of the sun, and anything Saturn-sized within half that distance. Something smaller and dimmer like a super-Earth could still lurk out there, unseen, but to find it with such easy serendipity in routine ALMA measurements seems statistically unlikely, astronomers say.

Mike Brown, a prominent Caltech astronomer and self-described “Pluto-killer” who discovered several large TNOs that dethroned the former planet, unleashed another statistical argument against the claimed new planets on Twitter. “If it is true that ALMA accidentally discovered a massive outer solar system object in its tiny, tiny, tiny, field of view,” Brown said, “that would suggest that there are something like 200,000 Earth-sized planets in the outer solar system. Which, um, no.”

“Even better,” he added later, “I just realized that this many Earth-sized planets existing would destabilize the entire solar system and we would all die.” That said, Brown notes, “the idea that there might be large planets lurking in the outer solar system is perfectly plausible.”

Many of the most cutting reactions came from astronomers discussing the results on a public Facebook group devoted to imaging exoplanets—that is, planets around other stars. After tweeting that the two papers “will launch 1,000 undoubtedly wrong blogs and news releases,” the University of Rochester, New York astronomer Eric Mamajek detailed what he believes to be serious inconsistencies in the measurements of motion and brightness for both objects. “‘Gna’ presumably stands for ‘Goofy Non-Asteroid,’” Mamajek quipped, before suggesting that the objects could perhaps be activity in far-away galaxies, simply misconstrued as being much closer to Earth. “Please pass whatever they are smoking in Onsala,” he added.

In the same group, Bruce Macintosh, an astronomer at Stanford University in California, noted the “astonishing coincidence” that the first two trans-Neptunian objects discovered by ALMA would be found right next to bright stars. More likely, Macintosh guessed, is that the putative objects are actually “some residual artifact”—mirages produced in the data by quirks in ALMA’s complex calibration methods.

Vlemmings insists that he and his colleagues have already carefully checked out these and several other scenarios, to no avail—whatever they are, the objects simply seem to be too bright and point-like to be explained away as far-off galaxies, and their proximity to bright stars, he says, actually helps the data calibration and reduces the likelihood of observational errors. “Still, we are certainly open to such options and have several times sent out queries to ALMA colleagues [asking] if they could conceive of how such point sources could be artificially created,” Vlemmings says. “None have yet said they think it could be done.” The trial of these claims in the court of public opinion has not come without its perks, Vlemmings adds. Though the sudden publicity was unwanted, “the most helpful feedback so far has been numerous offers to observe with other instruments.” With a little help from the rest of the astronomy community, evidence for—or against—the next Planet X may not be so far-off after all.

This Video Will Change Your Perception Of Planet Earth

Environment





Photo credit:

Paul L Dineen/Flickr. (CC BY 2.0)

You might know all the capitals of the world, but chances are your perceptions of Earth’s geography is pretty far off.

For example, did you know Italy can fit into the state of Alaska almost six times?

Business Insider has created this video to blow your geographical perception into tiny Liechtenstein-sized shards.

 

These Maps Will Show You Exactly How Pointless Daylight Savings Time Is

Environment





Photo credit:

Mindscape studio/Shutterstock

Daylight savings time (DST) was introduced over the course of the last century in many areas of the world to help decrease energy use and give people an extra hour of light in the summer. 

How To Make Someone Fall In Love With Science

The Brain





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Maxx-Studio/Shutterstock

Affairs of the heart are a very relative thing, often thought to be better grasped by the arts rather than science and statistics. However, there have been quite a few scientific studies that attempt to capture some objective truths on this very subject matter.

This Online Test Will Tell You Which Personality Traits You Have

The Brain





Photo credit:

Lewis Tse Pui Lung/Shutterstock

From altruistic daydreamers to short-tempered narcissists, each of us has our own pick ‘n’ mix composition of traits, temperaments and quirks. The International Personality Item Pool is considered one of the more thorough and established personality tests out there.