Tag: science

The mystery of Tabby’s Star deepens

11:15 pm

The uncertainty of science: New data from Kepler has made it even more difficult for scientists to explain the strange fluctuations and dimming of Tabby’s Star.

KIC 8462852, as it is more properly known, flickers so erratically that one astronomer has speculated that nothing other than a massive extraterrestrial construction project could explain its weird behaviour. A further look showed it has been fading for a century. Now, fresh analysis suggests the star has also dimmed more rapidly over the past four years – only adding to the enigma. “It seems that every time someone looks at the star, it gets weirder and weirder,” says Benjamin Montet at the California Institute of Technology, who led the study.

There are as yet no natural explanations for the star’s dimming.

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Sunspot ramp down continues

9:36 am

Below is NOAA’s monthly update of the solar cycle, posted by them on August 7. It shows the Sun’s sunspot activity in July, with annotations.

July 2016 Solar Cycle graph

The graph above has been modified to show the predictions of the solar science community. The green curves show the community’s two original predictions from April 2007, with half the scientists predicting a very strong maximum and half predicting a weak one. The red curve is their revised May 2009 prediction.

As expected, there was a recovery in sunspot activity in July compared to June. Also as expected, the recovery was not significant, so that it appears, based on the past two months, as if the ramp down to solar minimum is accelerating so that solar minimum will occur sooner than expected, possibly as soon as two years.

I would not put much stock on that prediction, however. When sunspot activity first reached this level during the past solar cycle in late 2005, it still took three more years before solar minimum was reached. If this cycle matches the last, that would mean that this cycle, from minimum to minimum, will have lasted 10 years, making a short solar cycle though not one of the shortest. However, it is more likely that the ramp down will stretch out, as it usually does, gliding downward to solar minimum in a slow gentle curve that makes for a full cycle of about 11 years.

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New evidence suggest lake once existed in Gale Crater

8:53 am

Scientists have concluded that mineral veins seen by Curiosity in Gale Crater were created when a lake existed there.

The study suggests that the veins formed as the sediments from the ancient lake were buried, heated to about 50 degrees Celsius and corroded. Professor John Bridges from the University of Leicester Department of Physics and Astronomy said: “The taste of this Martian groundwater would be rather unpleasant, with about 20 times the content of sulphate and sodium than bottled mineral water for instance!”

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SDO not returning data

8:55 am

For reasons that remain unexplained, the Solar Dynamics Observatory (SDO) did not return to science mode after it passed through the Moon’s shadow on August 2nd.

The only information about this on the SDO webpage simply states, ” The spacecraft did not go back into Science mode at the end of the transit. SDO FOT members are looking into the issue.” Spaceweather.com notes that “Since the transit no new data have appeared on SDO public websites.”

SDO has only been in orbit for six years. It would be a shame to lose it so quickly.

UPDATE: It appears that engineers are getting SDO back into operation. Hat tip James Fincannon.

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Moon Express gets FAA approval for Moon landing

2:59 pm

The competition heats up: Moon Express, one of the leading private competitors in the Google Lunar X-Prize, has gotten FAA approval for its planned 2017 Moon landing.

It is looking like 2017-2018 will be very exciting years for private space. We will not only see the first launches of privately-built manned spacecraft, we will see the first privately-built and -funded missions to both the Moon and Mars.

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The interior of Ceres

11:06 am

Using data from Dawn, scientists have created their first rough map of the internal structure of Ceres.

The data indicate that Ceres is “differentiated,” which means that it has compositionally distinct layers at different depths, with the densest layer at the core. Scientists also have found that, as they suspected, Ceres is much less dense than Earth, the moon, giant asteroid Vesta (Dawn’s previous target) and other rocky bodies in our solar system. Additionally, Ceres has long been suspected to contain low-density materials such as water ice, which the study shows separated from the rocky material and rose to the outer layer along with other light materials. “We have found that the divisions between different layers are less pronounced inside Ceres than the moon and other planets in our solar system,” Park said. “Earth, with its metallic crust, semi-fluid mantle and outer crust, has a more clearly defined structure than Ceres,” Park said.

Scientists also found that high-elevation areas on Ceres displace mass in the interior. This is analogous to how a boat floats on water: the amount of displaced water depends on the mass of the boat. Similarly, scientists conclude that Ceres’ weak mantle can be pushed aside by the mass of mountains and other high topography in the outermost layer as though the high-elevation areas “float” on the material below. This phenomenon has been observed on other planets, including Earth, but this study is the first to confirm it at Ceres.

In other words, Ceres behaves more like a semi-hardened blob of jello than a rock.

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Io’s atmosphere freezes and reinflates daily

9:47 am

New data from the ground-based Gemini telescope suggests that Io’s sulfur dioxide atmosphere freezes and then reinflates each time the moon flies through Jupiter’s shadow.

A study led by SwRI’s Constantine Tsang concluded that Io’s thin atmosphere, which consists primarily of sulfur dioxide (SO2) gas emitted from volcanoes, collapses as the SO2 freezes onto the surface as ice when Io is shaded by Jupiter. When the moon moves out of eclipse and ice warms, the atmosphere reforms through sublimation, where ice converts directly to gas.

The data is somewhat uncertain, however, as it based on only two observations.

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China’s Chang’e 3 finds no water on Moon

9:44 am

The uncertainty of science: After more than 2 1/2 years on the lunar surface China’s Chang’e 3 lunar lander has detected no water at its landing site.

This result, while not in direct conflict with the orbital data from India’s Chandrayaan-1, suggests that the question of water on the Moon is a very complex one. Chandrayaan-1 detected evidence that suggested their might be deposits of water in certain surface regions, locked up in the regolith. Chang’e 3 found no water at its specific location. The two results do not have to conflict, but the latter does raise the uncertainty of Chandrayaan-1’s detection.

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Japan’s troubled space agency

8:52 am

Link here. The article describes how JAXA has pulled some remarkable successes out of the jaws of failure, but in describing these stories it made me realize how many of these failures have occurred, far more than one should expect. Just consider:

  • Nozomi failed to enter Mars orbit when its main engine did not fire as planned. The mission was a total loss.
  • Akatsuki failed to enter Venus orbit when its main engine did not fire as planned. The mission has been partly saved by the use of the spacecraft’s attitude thrusters to put it into Venus orbit five years late.
  • Hayabusa-1 had enormous problems, and was barely able to return to Earth with barely any asteroid samples, as had been the plan.

This list is essentially Japan’s entire interplanetary program since 2000, all of which failed in some significant way. The recovery of Akatsuki and Hayabusa-1 were hailed as great achievements, but in retrospect they both indicated a serious quality control problem in Japan’s space program. The loss of their most recent science X-ray telescope, Hitomi, when a software error caused the spacecraft to breakup in orbit only one month after launch, illustrated this again.

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Juno swings back towards Jupiter

7:55 am

Juno has now passed the farther point from Jupiter in its first orbit and has started dropping back down to the gas giant.

Juno arrived at Jupiter on July 4, firing its main rocket engine as planned for 35 minutes. The flawless maneuver allowed Jupiter’s gravity to capture the solar powered spacecraft into the first of two 53.4-day-long orbits, referred to as capture orbits. Following the capture orbits, Juno will fire its engine once more to shorten its orbital period to 14 days and begin its science mission.

But before that happens, on Aug. 27, Juno must finish its first lap around Jupiter, with a finish line that represents the mission’s closest pass over the gas giant. During the encounter, Juno will skim past Jupiter at a mere 2,600 miles (4,200 kilometers) above the cloud tops.

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More Junk Science and Journalism

11:46 am

I can’t stand it. I just can’t stand it. It keeps happening and I just can’t stand it.

Yesterday there was this absurd short news piece posted on the website of the so-called journal Science, “Apollo astronauts much more likely to die from heart disease”. describing a research paper published by one of Nature’s side journals, Scientific Reports. Before I even looked at the story I said to myself, “How can they possibly come to that conclusion considering the tiny number of humans who have ever traveled beyond Earth orbit? The sample will simply be too small to allow for any such finding.”

Then I looked at the article and found my instincts confirmed. As Steve Milloy noted on his very aptly named website, Junk Science,

Yes, the result is based on a total of three (3) cases of heart disease deaths of out seven (7) Apollo astronauts. Past the vanishingly small sample size and even smaller number of cases, heart disease is a natural disease of aging and the Apollo lunar astronauts were 10 years older than the other comparison groups.

To put it more bluntly, this was a garbage piece of very bad science. While it was somewhat embarrassing for a Nature journal to publish it, it was far more disgraceful for the journal Science to highlight it. I, however, don’t have to join these two peer-review journals and participate in their stupidity, and thus I made no mention of the story on Behind the Black, because it is my policy to not waste much time on bad science, unless I think that bad science is going to have bad repercussions.

Well the bad repercussions have arrived. Since yesterday, the following so-called news organizations have run with this story, without the slightest indication that they have faintest understanding of science, statistics, or plain common sense:
» Read more

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Martian gullies not formed by water flow

9:38 am

The uncertainty of science: Spectroscopy of many of the gullies on Mars strongly suggests that water had nothing to do with their formation, even though these gullies resemble closely similar gullies on Earth that were carved by flowing water..

Color coding in light blue corresponds to surface composition of unaltered mafic material, of volcanic origin. Mafic material from the crater rim is carved and transported downslope along the gully channels. No hydrated minerals are observed within the gullies, in the data from CRISM, indicating limited interaction or no interaction of the mafic material with liquid water. These findings and related observations at about 100 other gully sites on Mars suggest that a mechanism not requiring liquid water may be responsible for carving these gullies on Mars. (Gullies on Mars are a different type of feature than seasonal dark streaks called recurring slope lineae or RSL; water in the form of hydrated salt has been identified at RSL sites.) [emphasis mine]

In other words, these gullies were formed by flowing lava, not water. Considering Mars’s lower gravity, one third that of Earth’s, we should not be surprised if lava is capable of doing things there that it is not generally capable of doing on Earth. In fact, we should remind ourselves constantly that Mars is an alien planet, and that conditions there are different enough to make any predictions based on our knowledge of Earth very unreliable.

More details here.

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Heading directly for Balanced Rock

9:32 am

Curiosity's course to Balanced Rock

As I predicted Sunday, the Curiosity science team is aiming the rover directly towards the gap in the mesas, dubbed the Murray Buttes, that also has the balanced rock seen in earlier images.

The image on the right shows the rover’s most recent two traverses, superimposed on a Mars Reconnaissance Orbiter image. I have cropped it to focus in on the area of most interest.

Based on the rover’s general rate of travel, I would expect them to enter the gap after about two or three more traverses. This means they will be there in about a week, since after each traverse they usually stop and do science and reconnaissance before resuming travel.

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ExoMars successfully completes long mid-course burn

9:13 am

ExoMars 2016, the European/Russia orbiter/lander mission on its way to Mars, successfully completed a 52 minute mid-course engine burn today in preparation for its October 19th arrival at Mars.

Officially known as the deep-space maneuver, DSM, it was the longest engine burn for the ExoMars-2016 mission before the Mars orbit insertion on October 19, 2016. As a result of the July 28 orbit correction, the spacecraft will need less propellant during its maneuvers in the vicinity of the planet and the Schiaparelli lander will experience slightly less thermal loads during its planned entry into the Martian atmosphere.

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Great Red Spot hottest spot on Jupiter

6:05 pm

Jupiter’s Great Red Spot, a giant storm that has been raging for at least three centuries, turns out to be the hottest spot on Jupiter.

They suspect that the spot is heated from below, but really understand much else, or even that.

Juno is specifically designed to study the weather patterns of Jupiter, so we will get some of these answers, plus a lot more questions, in the coming years as the spacecraft gathers its data.

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“They can’t be real.”

8:56 am

The uncertainty of science: Astronomers have now detected and measured a new class of large but very dim galaxy that previously was not expected to exist.

‘Ultradiffuse’ galaxies came to attention only last year, after Pieter van Dokkum of Yale University in New Haven, Connecticut, and Roberto Abraham of the University of Toronto in Canada built an array of sensitive telephoto lenses named Dragonfly. The astronomers and their colleagues observed the Coma galaxy cluster 101 megaparsecs (330 million light years) away and detected 47 faint smudges.

“They can’t be real,” van Dokkum recalls thinking when he first saw the galaxies on his laptop computer. But their distribution in space matched that of the cluster’s other galaxies, indicating that they were true members. Since then, hundreds more of these galaxies have turned up in the Coma cluster and elsewhere.

Ultradiffuse galaxies are large like the Milky Way — which is much bigger than most — but they glow as dimly as mere dwarf galaxies. It’s as though a city as big as London emitted as little light as Kalamazoo, Michigan.

More significantly, they have now found that these dim galaxies can be as big and as massive as the biggest bright galaxies, suggesting that, surprise!, there are a lot more stars and mass hidden out there and unseen than anyone had previously predicted.

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The Sun is blank again

2:01 pm

More signs that we are easing down to solar minimum: After a period of two weeks of sunspots, the Sun has once again gone blank.

It takes the Sun’s about four weeks to rotate and complete one “day”. What has essentially happened is that right now one face of the Sun is blank while the other face has sunspots. For two weeks, from the last week in June to the first week in July, the blank face was turned towards the Earth. Then the face with sunspots rotated into view for two weeks, and now the blank face has rotated back to face us.

Though new sunspots can always form on either face, I expect this blank stretch to last a few days, at least.

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