Tag: science

Giant iceberg breaks off from Antarctica

11:13 pm

We’re all gonna die! A giant section of the Antarctic ice shelf, about the size of the state of Delaware, has finally broken off from the main ice cap.

The Science article immediately tries to tie this event to global warming, as articles in this pro-global warming journal are always eager to do. The problem is that there is no way to really do that, as the author himself is forced to admit.

Climate change has a new poster child: a massive iceberg the size of Delaware—one of the largest ever recorded—that early this week calved off Larsen C, the largest remaining ice shelf off the Antarctic Peninsula, scientists announced today. Although researchers cannot explicitly connect the calving event to warming air or water, those monitoring the event are now concerned that the entire shelf, after shedding more than 12% of its area, could follow the fate of its more northern peers, Larsens A and B, which collapsed entirely in 1995 and 2002, respectively.

The Antarctic icecap has been growing in recent decades. Just because a big piece broke off this week tells us nothing about the overall global climate. Furthermore, take a look at the map at the link. On the scale of the entire Antarctica icecap this iceberg is actually only a tiny piece. Such calving events are actually the normal process that occurs at the icecap, and every scientist who studies this subject knows it. Like a glacier, the icecap accumulates snow and ice in its center, which slowly flows outward to the sea, where it eventually breaks off to rejoin the Earth’s normal water cycle. There presently is little evidence that more ice is exiting the icecap than is accumulating at its center.

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Juno images of Great Red Spot released

5:42 pm

The Juno science team has released the images taken by Juno as it flew past Jupiter’s Great Red Spot on June 11.

The three images at the link were all processed by citizen scientists, who took the raw images provided immediately and enhanced the colors. Not surprisingly, the images reveal that there are storms within storms within storms inside the Spot, which itself is a storm, the largest in the solar system.

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Mars rover update: July 12, 2017

2:49 pm

Summary: Curiosity looks at some big dune ripples, then creeps up hill. Opportunity tests its wheels.

Curiosity

For the overall context of Curiosity’s travels, see Pinpointing Curiosity’s location in Gale Crater.

The interior of a dune ripple

Since my last update on June 23,, Curiosity has worked its way around and, for a few days, even into the small sandy field at the base of Vera Rubin ridge. The scientists noticed that the sandy here had a series of large ripples, and they wanted to take a close look at at least one. The image on the right, cropped to show here, was taken shortly after they had the rover drive through one ripple in order to expose its interior. You can see the robot arm directly above the cut created by the rover’s wheels. On the cut’s wall several distinctly different toned layers are visible. A close look reveals that they are wavy, and probably indicate numerous and repeated overlays as the wind brushes a new layer of dust on top of old layers, time after time. The different tones indicate a change in the material’s composition, which could reveal something about some past events in either Mars’ weather or geology.

In order to decipher this information, however, they will need to be able to date the layers, and figure out when each tonal change happened. I am not sure Curiosity can do this, especially since they have not scooped up any of this dust for later analysis.

They are now approaching Vera Rubin Ridge, and should climb up onto in the coming weeks. At that point they will move off the Murray Formation, where they have been since March 2016, made up of dried and ancient crushed mud, and up onto a lighter, yellowish layer of rock, dubbed the Hematite Unit. This October 3, 2016 press release. gives a good outline of the geology of these regions.
» Read more

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ESA unveils dual orbiter mission to Mercury

10:31 am

After twenty years of development, the European Space Agency this week finally unveiled the completed dual orbiters that it hopes to launch on a seven year journey to Mercury in October 2018.

The 4,100-kilogram BepiColombo consists of two orbiters that will launch together — the ESA-managed Mercury Planetary Orbiter (MPO) and the JAXA-owned Mercury Magnetospheric Orbiter (MMO). The two spacecraft will be delivered to the orbit around Mercury stacked on top of each other by the Mercury Transfer Module (MTM). During the seven-year journey, the MMO will be shielded from the sun by the MMO Sunshield and Interface Structure (MOSIF), which will also serve as a mechanical and electrical interface between the two orbiters.

“MPO focuses on the planet, the surface and the interior size,” said Reininghous. “The orbit is a polar one — 480km times approximately 1500km — a little bit elliptical but extremely close to the planet as such with a return period of 2.3 hours. The data return is estimated at 1.5 gigabit per year.”

The MMO will focus on the planetary environment including the planet’s atmosphere, according to Reininghous. “The orbit is also polar but far more elliptical — 590 km times approximately 11,700 km. It has a period of 9.3 hours. The data return is approximately 10 percent of what we expect from the MPO.”

The European orbiter is much larger and more expensive, with Japanese probe budget being about a tenth the cost.

According to ESA, the mission took so long to build because in 2004, after about seven years of development, ESA suddenly realized that its orbiter’s thermal protection was inadequate, and required a complete redesign. To me, this is either outright incompetence (they knew from the start they were going to Mercury) or a clever way to extend the funding so that it provides an entire lifetime’s work for its builders. Think about it. Twenty-one years from concept to launch, then seven years to fly to Mercury, and then one to two years in orbit. That’s more than thirty years for this single mission.

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New Horizons’ next target might be smaller than predicted

10:43 am

The uncertainty of science: Because all attempts to observe an occultation of a star on June 3 by New Horizons’ next target failed, astronomers now think Kuiper Belt object 2014 MU69 is much smaller than previously believed.

The discovery observations using Hubble and other ground-based telescopes had estimated its size as between 12 to 25 miles in diameter. The null result from the June 3 event suggests it is smaller than that.

More occultations are upcoming, so stay tuned.

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Fastest stars in Milky Way escaped from Large Magellanic Cloud?

9:01 am

Astronomers have proposed that the fastest stars in Milky Way actually escaped from the Large Magellanic Cloud (LMC), the largest nearby satellite dwarf galaxy.

The LMC is the largest and fastest of the dozens of dwarf galaxies in orbit around the Milky Way. It only has 10% of the mass of the Milky Way, and so the fastest runaways born in this dwarf galaxy can easily escape its gravity. The LMC flies around the Milky Way at 400 kilometres per second and, like a bullet fired from a moving train, the speed of these runaway stars is the velocity they were ejected at plus the velocity of the LMC. This is fast enough for them to be the hypervelocity stars. “These stars have just jumped from an express train – no wonder they’re fast,” said co-author Rob Izzard, a Rutherford fellow at the Institute of Astronomy. “This also explains their position in the sky, because the fastest runaways are ejected along the orbit of the LMC towards the constellations of Leo and Sextans.”

Their calculations predict how many hypervelocity stars should be detectable and where in the sky they should be. If right, the data from Gaia, soon to be released, should prove them right or wrong.

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New data suggests Sun undergoing fundamental changes

8:40 am

The uncertainty of science: New data, when compared with similar data collected over decades, suggests the Sun’s solar cycle is undergoing some fundamental changes.

In work just published in the Monthly Notices of the Royal Astronomical Society, the team shows that the interior of the Sun has changed in recent years, and that these changes persist in the current cycle. In combination with theoretical models, the observations suggest that the magnetic field distribution in the outer layers may have become a bit thinner. Other seismic data shows that the rotation rate of the Sun has also undergone some changes in the way the Sun rotates at different latitudes.

“Again, this is not how it used to be and the rotation rate has slowed a bit at latitudes around about 60 degrees. We are not quite sure what the consequences of this will be but it’s clear that we are in unusual times. However, we are beginning to detect some features belonging to the next cycle and we can suggest that the next minimum will be in about two years,” says Elsworth.

First, they don’t know what will happen because of these changes. Second, their data confirms that the solar minimum will occur in about two years, which would make this cycle only 9 years long, one of the shortest but also one of the weakest that has been observed, two things that previously had never gone together.

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Sunspot update for June 2017

11:47 am

Today NOAA posted its monthly update of the solar cycle, covering sunspot activity for June. As I have done every month since 2010, the graph is posted below, with annotations.

June 2017 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.

Sunspot activity in June was almost exactly the same as in May, and thus continued the overall downward trend that is below the 2007 low prediction and that suggests that this very weak solar maximum will end much earlier than predicted, and will make it an unprecedented short but weak cycle. The Sun is once again blank today for the first time in about two weeks, repeating the pattern we have seen for several months where, because one hemisphere of the Sun is blank while the other hemisphere has some sunspots, the rise and fall of the sunspot counts tracks the 27-day solar rotation almost precisely.

There continues to be evidence that the Sun is undergoing significant changes this solar cycle, all of which are pointing to the possibility that a grand minimum is coming, with no sunspots for decades. And as I have said now monthly for six years, past grand minimums have consistently occurred at the same time the Earth’s climate has cooled. The scientific link remains unclear, but if we should undergo a grand minimum in the coming decades, we will finally have the opportunity to find out what that link is.

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The soft craters of Epimetheus

9:24 am

The soft craters of Epimetheus

Cool image time! The image on the right, reduced in resolution to show here, is the highest resolution image that Cassini has taken of the Saturn moon Epimetheus, taken from only 9,300 miles away on February 21, 2017.

Epimetheus (70 miles or 113 kilometers across) is too small for its gravity to hold onto an atmosphere. It is also too small to be geologically active. There is therefore no way to erase the scars from meteor impacts, except for the generation of new impact craters on top of old ones.

Below is the inset at full resolution, showing several craters, with ponds of dust on their floor. Overall, the surface of this tiny moon looks soft. The craters are all shallow, as if any impact merely plunged into a blob of ice cream. Any ejecta from those impacts eventually rained back down, and then settled slowly in the moon’s low points, forming those ponds of dust.

close-up of soft craters

In many ways this image is very revealing, as it shows what the early accretion process of any planetary body will look like. Nor is this unique. Earlier images taken of the asteroid Eros by the NEAR probe saw many of these same features, as have images of Saturn’s other small moons. In the early stages, new material gets absorbed easily because it finds it easy to bore into the body of the newly formed and not very dense planetary body. There isn’t much ejecta, and what there is doesn’t fly that far away so that it can settle back down on the surface and add to the new body’s total mass.

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As predicted climate scientists begin adjusting satellite data to fit models

12:37 pm

If the facts don’t fit the theory, change the facts! The scientists in charge of the climate satellite data produced by Remote Sensing Services (RSS) in California have decided to adjust their satellite data to increase the warming trend since 2000 and make that data more closely match the surface temperature data that NASA and NOAA have already altered to show that same warming trend.

Researchers from Remote Sensing Systems (RSS), based in California, have released a substantially revised version of their lower tropospheric temperature record. After correcting for problems caused by the decaying orbit of satellites, as well as other factors, they have produced a new record showing 36% faster warming since 1979 and nearly 140% faster (i.e. 2.4 times larger) warming since 1998. This is in comparison to the previous version 3 of the lower tropospheric temperature (TLT) data published in 2009.

How have they done this? They made several changes, the first two of which appear quite questionable. First, they addressed the “time of observation issue.” There is a belief among some climate scientists that the time temperature readings were taken can introduce an error in the long term trends.

To account for changes in observation times, the RSS group used a number of different approaches and models to try and estimate what the temperature would have been if the measurement time remained constant. This involves a combination of satellite observations (when different satellites captured temperatures in both morning and evening), the use of climate models to estimate how temperatures change in the atmosphere over the course of the day, and using reanalysis data that incorporates readings from surface observations, weather balloons and other instruments.

Depending on the time of the observation correction approach chosen, the resulting temperature trends between 1979 and 2016 ranged from as low as 0.13C per decade to as high as 0.22C per decade. The RSS group ultimately decided that the most reasonable set of parameters give a temperature trend of 0.17C. [emphasis mine]

I am puzzled by this, since satellites in orbit do not take readings at one particular time, but at a wide range of times. In fact, I would say that the number of readings, at all different times, would easily introduce enough randomness into the results that any error would be insignificant. Instead, these scientists have decided to adjust the raw data to add a warming trend of almost a tenth of a degree centigrade.

Next, they simply decided that the data coming from some satellites should be excluded.
» Read more

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Astronomers take best image of Betelgeuse yet

5:21 pm

Betelqeuse

Using the Atacama Large Millimeter/submillimeter Array Telescope (ALMA), astronomers have produced the best picture of the red giant star Betelgeuse taken so far.

Using ESO’s Very Large Telescope astronomers discovered a vast plume of gas almost as large as our Solar System. Astronomers have also found a gigantic bubble that boils away on Betelgeuse’s surface. These features help to explain how the star is shedding gas and dust at tremendous rates (eso0927, eso1121). In this picture, ALMA observes the hot gas of the lower chromosphere of Betelgeuse at sub-millimeter wavelengths — where localised increased temperatures explain why it is not symmetric.

The image on the right is that image, slightly reduced to post here. The bulge on the star’s left illustrates the unevenness of the star’s upper atmosphere. I suspect that continuous observations would reveal the outer atmosphere waxing and waning almost like the stuff inside a lava lamp.

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Astronomers discover complex molecules in protostar accretion disk

10:18 am

Astronomers have discovered several complex molecules in the accretion disk surrounding a very young baby star about 1300 light years away in the constellation Orion.

The research team’s ALMA observations have clearly detected an atmosphere of complex organic molecules above and below the disk. These include methanol (CH3OH), deuterated methanol (CH2DOH), methanethiol (CH3SH), and formamide (NH2CHO). These molecules have been proposed to be the precursors for producing biomolecules such as amino acids and sugars. “They are likely formed on icy grains in the disk and then released into the gas phase because of heating from stellar radiation or some other means, such as shocks,” says co-author Zhi-Yun Li of the University of Virginia.

What is even most interesting about this discovery is that these complex molecules are not scattered throughout the disk, but are concentrated in regions above and below its central plane, what the astronomers are labeling “an atmosphere.” This suggests that differentiation — the same process that separates the heavier molecules from lighter ones both in centrifuges and in the cores of planets — occurs quickly in accretion disks as well.

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A river canyon on Mars

11:02 am

A river on Mars

Cool image time! The image on the right, reduced in resolution significantly to show here, was taken by the Themis camera on Mars Odyssey, and shows an unnamed canyon on Mars. Be sure to click on the image to see the full resolution version.

This canyon of course no longer has anything flowing in it. Moreover, it is not clear whether this was formed by water or lava. Unfortunately, the image is part of a series of “Art images” from Mars Odyssey, where they pick an image and suggest it looks like something else. In this case, they are claiming this looks like a “snake, slithering down the image.” Cute, but not very helpful. And unfortunately, they don’t add any further details at all about the image or its location. The context image suggests this canyon is next to a volcano.

After doing further research at the Themis image site, I was able to locate this image on Mars (using latitude 32.0515 and longitude 152.236 given at the link) and look at the images surrounding this one. Further research identified the volcano as Hecates Tholus in the Elyesium Plantia region to the west of Mars’s giant volcanoes.

Looking at all the nearby Mars Odyssey images, it appears that there are a lot of flows like this in this area, and all of them appear to be lava flows, with this one being the largest. A close look at the area just to the south of where the deep canyon opens out shows that the small surface flow draining into the canyon also appears to sit on much larger surface flows (at least two) that left the surface higher than the surrounding terrain.

Elyesium Plantia itself is a plateau, somewhat close to the border between Mars’s southern highlands and the northern plains where some scientists think an ocean might have once existed. Thus, it makes sense that the canyon drains north, as it is following the dip down to those northern low plains.

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Uranus’s magnetic field switches on and off daily

9:54 am

Using data from the Voyager 2 flyby of Uranus in 1986, scientists now think that the gas giant’s magnetic field switches on and off each day as the planet rotates.

Uranus’s magnetosphere, in contrast [to Earth], exhibits precise regularity in its mode changes. This, say the researchers, is because it lies at an angle of roughly 60 degrees to the planet’s spin axis, causing its interaction with incoming solar winds to vary dramatically during the 17 hours it takes for a full rotation. “Uranus is a geometric nightmare,” says Paty.

“The magnetic field tumbles very fast, like a child cartwheeling down a hill head over heels. When the magnetised solar wind meets this tumbling field in the right way, it can reconnect and Uranus’s magnetosphere goes from open to closed to open on a daily basis.”

The researchers suggest the robust and regular changes to the magnetosphere may mean that the icy planet has spectacular auroras across its breadth every day.

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Orbital motion of a binary black hole detected for the first time

10:19 am

Astronomers have for the first time measured the orbital motion of two supermassive black holes that orbit each other.

Based on the initial data, the two black holes appear to orbit each other every 30,000 years. Eventually, they will spiral into each other, merge, and in the process produce ripples in the surrounding gravitational field that will be detectable by future gravitational wave detectors.

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Success of test mission paves way for orbiting gravitational wave detector

9:57 am

The success of LISA Pathfinder during the past year to test the technology for building an orbiting gravitational wave detector has now made it possible for Europe to approve construction of the full scale telescope, set to launch in the 2030s.

The LISA Pathfinder mission, launched in late 2015, beat its precision target by a factor of 1,000 and quieted critics who have doubted its potential, says project scientist Paul McNamara, an astrophysicist at ESA in Noordwijk, the Netherlands. “This is not the impossible task that some people believed it was.”

Currently set to fly in 2034, the full-scale Laser Interferometer Space Antenna (LISA) will be the space analogue of the Laser Interfero-meter Gravitational-Wave Observatory (LIGO), two machines in the United States — each with a pair of 4-kilometre-long arms — that first detected the ripples by ‘hearing’ the merger of two black holes. LISA’s three probes will fly in a triangle, millions of kilometres apart, making the mission sensitive to much longer gravitational waves, such as the ripples produced by the collisions of even larger black holes.

The article also notes that the European Space Agency also approved two other large missions, one to launch in 2022 and go the moons of Jupiter, another an X-ray observatory that will launch in 2028.

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Climate scientists once again claim ozone layer is threatened

9:40 am

Crying wolf! New research by climate scientists suggests that the Earth’s ozone layer is once again threatened by modern human technology.

Industrial emissions of a chemical commonly used in solvents, paint removers, and the production of pharmaceuticals have doubled in the past few years, researchers have found, which could slow the healing of the ozone layer over Antarctica anywhere between 5 and 30 years—or even longer if levels continue to rise.

The findings are “frightening” and “a big deal,” says Robyn Schofield, an environmental scientist at the University of Melbourne in Australia who was not involved with the work.

They might be right, but why should anyone believe them? The climate field has been spouting doomsday predictions about global warming and sea level rise now for more than 20 years, none of which have come true. As far as I can tell, this might be more of the same thing.

Worse, it might not, but by not being honest with so many other climate predictions the field has lost all political credibility, a great tragedy for them and for all of science. It will take decades, if ever, for them to recover that credibility.

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Mars rover update: June 23, 2017

11:11 am

Summary: Curiosity continues up hill. Opportunity has wheel problems.

Curiosity

For the overall context of Curiosity’s travels, see Pinpointing Curiosity’s location in Gale Crater.

The march up Mt Sharp continues. Since my last update on May 15, Curiosity has continued working its way up towards what the science team has named Vera Rubin Ridge, the beginning of a lighter, yellowish layer of rock, dubbed the Hematite Unit, that sits higher up the mountain’s slope. They have been traveling on the Murray Formation now for more than a year, since March, 2016, so entering this new layer of geology is eagerly anticipated by the science team. (This October 3, 2016 press release. gives an overall picture of the geology Curiosity is traversing.)

Reader Phil Veerkamp sent me a beautiful panorama he stitched together from recent Curiosity images of Vera Rubin Ridge, directly to the south of the rover and higher up hill. Below is a reduced resolution version. Be sure you click on it to explore the full resolution image. This is a new type of terrain, significantly different than anything Curiosity has seen up to now. It also appears that the rover will see far less dust, and might be traveling mostly over solid boulders. Below I have cropped out a very small section of the ridge line near the center of the full image, just to illustrate this.
» Read more

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