Tag: science

Sunspot ramp down resumes

9:31 am

On Monday NOAA posted its monthly update of the solar cycle. I am posting it here, as I do every month, with annotations to give it context.

September 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.

After two months of increased sunspot activity, the decline in sunspots resumed in September, though activity did not drop significantly. Overall though, the ramp down towards the next solar minimum continues to track quite closely the ramp down predicted by weak prediction made by half the solar science community back in 2007 (the lower green curve above). These scientists however do not have much to brag about. Their same prediction completely missed the ramp up, which happened a year later than predicted, as well as the activity peak, which was far weaker than predicted.

In fact, the ramp down now continues to point to the possibility that this very weak solar cycle will also be a very short one, something that is quite unprecedented, and suggests that we might be seeing the lead in to another Grand Minimum, where there are no sunspots for decades. Since no one understands yet exactly why such grand minimums happen, however, this remains pure speculation. We will only find out by watching what happens, as it happens.

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Predicting the next Martian global dust storm

5:22 pm

Scientists think they now have a method to predict the next global-wide dust storm on Mars, and based on this theory they predict it will happen very soon.

Global dust storms on Mars could soon become more predictable — which would be a boon for future astronauts there — if the next one follows a pattern suggested by those in the past. A published prediction, based on this pattern, points to Mars experiencing a global dust storm in the next few months. “Mars will reach the midpoint of its current dust storm season on October 29th of this year. Based on the historical pattern we found, we believe it is very likely that a global dust storm will begin within a few weeks or months of this date,” James Shirley, a planetary scientist at NASA’s Jet Propulsion Laboratory, Pasadena, California.

This is most interesting because my next rover update, later today or tomorrow, is going to note the increasingly dusty atmosphere in Gale Crater. It isn’t a global dust storm, but maybe it is indicative of one that is about to happen.

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The mystery of Tabby’s star deepens

7:07 am

Astronomers looking at the light variations of the star dubbed by some Tabby’s star have become even more baffled.

Spurred by a controversial claim that the star’s brightness gradually decreased by 14 percent from 1890 to 1989, Montet and Simon decided to investigate its behavior in a series of Kepler calibration images that had not previously been used for scientific measurements. “We thought that these data could confirm or refute the star’s long-term fading, and hopefully clarify what was causing the extraordinary dimming events observed in KIC 8462852,” explained Simon.

Simon and Montet found that, over the first three years of the Kepler mission, KIC 8462852 dimmed by almost 1 percent. Its brightness then dropped by an extraordinary 2 percent over just six months, remaining at about that level for the final six months of the mission. The pair then compared this with more than 500 similar stars observed by Kepler and found thata small fraction of them showed fading similar to that seen in KIC 8462852 over the first three years of Kepler images. However, none exhibited such a dramatic dimming in just six months, or a total change in brightness of 3 percent.

“The steady brightness change in KIC 8462852 is pretty astounding,” said Montet. “Our highly accurate measurements over four years demonstrate that the star really is getting fainter with time.  It is unprecedented for this type of star to slowly fade for years, and we don’t see anything else like it in the Kepler data.” 

At the moment, there is no good theory based on what astronomers know of stellar evolution to explain this star’s behavior. This does not mean the only explanation left is that aliens are building a Dyson sphere around the star, but it also leaves everyone at a loss to explain what is happening.

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Curiosity moves on

8:55 pm

The Curiosity science team today put out press release summarizing what they have accomplished at Murray Buttes and what they hope to do next.

For those who have been reading my weekly rover updates on Behind the Black, most of this release will be old news. However, the release did provide the following interesting geological information that supplements what I have been reporting:

This latest drill site — the 14th for Curiosity — is in a geological layer about 600 feet (180 meters) thick, called the Murray formation. Curiosity has climbed nearly half of this formation’s thickness so far and found it consists primarily of mudstone, formed from mud that accumulated at the bottom of ancient lakes. The findings indicate that the lake environment was enduring, not fleeting. For roughly the first half of the new two-year mission extension, the rover team anticipates investigating the upper half of the Murray formation. “We will see whether that record of lakes continues further,” Vasavada said. “The more vertical thickness we see, the longer the lakes were present, and the longer habitable conditions existed here. Did the ancient environment change over time? Will the type of evidence we’ve found so far transition to something else?”

The “Hematite Unit” and “Clay Unit” above the Murray formation were identified from Mars orbiter observations before Curiosity’s landing. Information about their composition, from the Compact Reconnaissance Imaging Spectrometer aboard NASA’s Mars Reconnaissance Orbiter, made them high priorities as destinations for the rover mission. Both hematite and clay typically form in wet environments.

It also appears that the problems they had while doing the last drill hole were related to the electrical design flaw of Curiosity’s drill. It caused a short circuit this time, which is worrisome based on what I understand because this design flaw has the capability of shorting out the rover’s entire electrical system, ending the mission.

I will post a new rover update later this week, once I get back from Illinois.

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Dark matter unnecessary?

9:06 pm

The uncertainty of science: A new analysis of the infrared data from 153 galaxies using the Spitzer Space Telescope suggests that dark matter might not be necessary to explain the rotation of galaxies.

First, this concise and nicely written explanation from the link of why dark matter has been proposed:

Newton’s laws of motion predict that planets that revolve closer to a star move faster than those that are farther away. In principle this should also hold true for stars circling the cores of galaxies, but for nearly a century, astronomers have seen that stars near the outskirts of galaxies orbit at nearly the same velocities as ones near galactic centers.

To explain why these outlying stars travel as quickly as they do without flying out into the void beyond, researchers came up with the idea of dark matter, a substance whose gravitational pull is thought to keep whirling stars in check. Scientists have largely ruled out all known particles as possible explanations for dark matter, and the consensus is that dark matter must be a kind of invisible, intangible material that is only detectable via its gravitational influence.

However, despite decades of trying, researchers have failed to capture a single mote of dark matter, even though it is supposed to make up roughly five-sixths of all matter in the universe. This raises the possibility that dark matter might not be real.

The new research, which I must admit I do not really understand, supposedly suggests that dark matter is unnecessary to explain the motions of stars.

Previous analyses of the orbital velocities of the stars in galaxies often depended on visible wavelengths of light. However, the stars that produce the most visible light are relatively short-lived and prone to fluctuations, and so may not provide the best picture of how matter is scattered overall throughout a galaxy. Instead, McGaugh and his colleagues analyzed near-infrared images collected by NASA’s Spitzer Space Telescope over the past five years. “The stars that generate the most near-infrared light are red giants, that are pretty stable in their output, and so are much better representative of a galaxy’s total mass of stars,” McGaugh said.

The researchers found an extraordinarily close association between the location of normal matter and the way it accelerates around the centers of galaxies. “We were surprised at how tight that relationship was,” McGaugh said. “It looks tantamount to a law of nature.”

Neither the article nor the scientists who did this research however explain clearly how this tight association negates the need for dark matter.

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Keeping the Deep Space Network working

9:12 am

According to this article in the journal Science, planetary scientists are increasingly worried about the future of the Deep Space Network (DSN), operated by JPL and that they use to communicate with their unmanned planetary probes.

For most of its life, the network, run by the Jet Propulsion Laboratory (JPL) in Pasadena, California, has been metronomic in its reliability. Its three sites, spaced 120° apart around the globe, all have a 70-meter dish built in the 1960s or ’70s, and several newer, 34-meter dishes, which can be arrayed together to match the larger dishes’ downlink performance. The network allows continuous contact with spacecraft anywhere in the solar system—or beyond it, as in the case of Voyager 1, which officially entered interstellar space in 2013. Currently, 35 missions rely on the DSN.

Ironically, the glitches this past December and January largely stemmed from problems with the network’s newest 34-meter antenna, DSS-35, in Canberra, which began operating in 2014, NASA says. Rain and dust compromised an instrument that helps aim it, several other pointing components overheated, and contaminants leaked into a cryogenic refrigerator used to cool an amplifier. NASA says these problems have mostly been fixed, and the Canberra station’s reliability will increase when its next 34-meter antenna, DSS-36, begins operating on 1 October.

Staffing issues have also compounded the hardware problems. In January, the Magnetospheric Multiscale mission, which measures the boundary between Earth’s magnetic field and the solar wind, was, like Cassini, having trouble connecting to DSS-35. Communications could have shifted to another Canberra antenna. But on 22 January, a snowstorm shut down the Goddard Space Flight Center in Greenbelt, Maryland. No one was there to reconfigure the spacecraft, and so the retrieval of a day’s worth of data was delayed.

While there has been a tendency to take the DSN for granted, much of this article seems to me to be a lobbying ploy for more money, budget increases that really aren’t needed that desperately. Almost all the problems listed in the article as well as in the quote above are not really from budgeting problems. In the first case above the failure came from a new antenna, showing that funds had been provided to upgrade the network’s equipment. The second case above was simply a problem caused by an unusual snowstorm.

Moreover, the article noted how Europe has finally built its own network to provide communications for its own planetary probes as well as redundancy to the American network. In addition, the U.S. is negotiating partnerships with several other countries to further supplement its DSN.

In other words, there really isn’t a problem here. The article is informative about this often ignored but essential component of planetary research, but when you read it ignore the pleas for more cash.

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The interior of Comet 67P/C-G

8:56 am

The Rosetta science team has released a summary of what they have learned about the interior of Comet 67P/C-G.

Essentially, they have found that the comet’s interior has a rather uniform and soft and fluffy interior, with few voids or dense pockets. They also found that the comet’s two lobes almost certainly came from two different objects that somehow made contact and stuck to each other. And finally, it appears that the upper few feet of the surface of the smaller lobe where Philae landed is different than its interior, a difference likely caused by the surface’s exposure to the Sun.

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Roman coins found in Japan

9:30 am

The mysteries of science: Archaeologists have uncovered Roman coins in a 13th century Japanese castle in Okinawa.

An X-ray analysis of the dime-sized coins showed some were embossed with Roman letters and possibly the image of Emperor Constantine I and a soldier holding a spear. Several others dated from a later period — the 17th century Ottoman empire.

Researchers were left scratching their heads about how the coins ended up at the castle in faraway Okinawa, which was built sometime in late 13th or early 14th century and abandoned about 200 years later. It was once the residence of a feudal lord, whose wealth was linked to regional trade but he was not known to have had business ties with Europe.

It is likely that the coins were obtained as curiosities by someone living at the castle, but the specific circumstances remain unknown.

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An ancient volcanic mountain chain on Mars

10:10 am

Using data from Mars Odyssey scientists have determined that a mountain chain on Mars was likely created as a chain of volcanoes.

They analyzed the geography and mineralogy of this area they termed Greater Thaumasia, which is about the size of North America. They also studied the chemistry of this area based on Gamma Ray Spectrometer data collected by the Mars Odyssey Orbiter, which was launched in 2001. What they found was the mountain ridge that outlines Greater Thaumasia was most likely created by a chain of volcanoes.

Their research also looked to see if water influenced the mountains’ formation and found no evidence for it. The mountain chain itself is south of the giant Valles Marineris canyons and southeast of the Tharsis region where Mars’ biggest four volcanoes are located.

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Water plumes on Europa?

11:40 am

New data from the Hubble Space Telescope suggests that there might be active water plumes issuing from Europa that are fed by the planet’s underground ocean.

In 10 separate occurrences spanning 15 months, the team observed Europa passing in front of Jupiter. They saw what could be plumes erupting on three of these occasions.

This work provides supporting evidence for water plumes on Europa. In 2012, a team led by Lorenz Roth of the Southwest Research Institute in San Antonio, detected evidence of water vapor erupting from the frigid south polar region of Europa and reaching more than 100 miles (160 kilometers) into space. Although both teams used Hubble’s Space Telescope Imaging Spectrograph instrument, each used a totally independent method to arrive at the same conclusion.

These results are very very uncertain. As the lead scientist noted twice during the press conference, the data is at the very limits of Hubble’s capabilities. I would not be surprised at all if later observations find that it is in error.

In fact, the press conference itself was more a PR event to lobby for Hubble as well as the James Webb Space Telescope than it was a description of a new discovery. The discovery itself was given a much bigger tease than it really deserves, considering the very uncertain nature of its data. I am a big fan of Hubble, as anyone who has read anything I have written in the past two decades. Nonetheless, I find this blatant lobbying very annoying. Also very annoying will be the naive willingness of many in the press to buy into this story. Expect a lot of silly stories today and tomorrow screaming that water jets coming from Europa have been definitely photographed by Hubble.

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Mars’ weird windblown surface

1:39 pm

Wind scoured Martian surface

Cool image time! The image on the right, taken by Mars Reconnaissance Orbiter (MRO) and cropped from a wider view of a small crater and a small volcano caldera, certainly appears blurred and out of focus. Is MRO malfunctioning?

Nope. The blurring is actually an optical illusion caused almost entirely by our own assumptions of what a planet surface should look like combined with the alien processes occurring on Mars that have no equivalent here on Earth.

Below the fold is a wider view from the full image, showing the area of the cropped image to the right as well as the entire crater. Below that is another full resolution inset, this time showing the features on the crater rim that are sharp and stand out clearly. The blurriness of the rest of the image is not because the image is out-of-focus, but because a steady northwest-to- southeast wind has distorted everything in the same direction.
» Read more

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The outbursts on Comet 67P/C-G

9:52 am

The Rosetta science team has released a detailed analysis of the jets and outbursts that they observed coming from Comet 67P/C-G during the comet’s close approach to the Sun.

Brief but powerful outbursts seen from Comet 67P/Churyumov–Gerasimenko during its most active period last year have been traced back to their origins on the surface.

In the three months centred around the comet’s closest approach to the Sun, on 13 August 2015, Rosetta’s cameras captured 34 outbursts. These violent events were over and above regular jets and flows of material seen streaming from the comet’s nucleus. The latter switch on and off with clockwork repeatability from one comet rotation to the next, synchronised with the rise and fall of the Sun’s illumination.

By contrast, outbursts are much brighter than the usual jets – sudden, brief, high-speed releases of dust. They are typically seen only in a single image, indicating that they have a lifetime shorter than interval between images – typically 5–30 minutes. A typical outburst is thought to release 60–260 tonnes of material in those few minutes.

They have also released a new image taken by the navigation camera of Rosetta’s September 30th landing zone.

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Big warming, or no warming, depending on dataset

5:20 pm

The uncertainty of science: Depending on the dataset, the most up-to-date climate data now shows either no warming since 1993, no warming since 1996, or significant warming continuously since then.

On several different data sets, there has been no statistically significant warming for between 0 and 23 years…. Cl stands for the confidence limits at the 95% level.

The details for several sets are below.

  • For UAH6.0: Since August 1993: Cl from -0.006 to 1.810. This is 23 years and 1 month.
  • For RSS: Since December 1993: Cl from -0.008 to 1.746. This is 22 years and 9 months.
  • For Hadsst3: Since December 1996: Cl from -0.022 to 2.162 This is 19 years and 9 months.
  • For Hadcrut4.4: The warming is statistically significant for all periods above three years.
  • For GISS: The warming is statistically significant for all periods above three years.

The quote above lists all the major climate datasets that everyone in the climate field uses. I’ve rearranged the order from the original to put similar datasets together and thus make it easier to digest the information.

The first two datasets are from satellite data. The Hadcrut datasets both use historical ground and sea surface temperature records and are both produced by the Climate Research Unit headed by Phil Jones, who when other scientists asked him for his raw original data in order to check it admitted that he had lost it. Jones was also one of the scientists whose climategate emails revealed a desire to destroy the careers of any skeptics, prevent their work from being published, and an effort to conceal or change data that contradicted the theory of global warming. GISS is the Goddard Institute for Space Sciences, run for decades by global warming advocate James Hansen and now the source of today’s claims that every month of every year is the hottest ever recorded. GISS is also the NASA institute that has been adjusting past datasets to cool the past and warm the present, thus creating a significantly steeper rise in global temperature than is shown by the original raw data.

Of these datasets, three show no significant warming in the past two decades, while two show significant warming. Which is it? Your guess is as good as mine. However, I must point out that the two datasets that show statistically significant warming have both come under question in the past few years because of questionable science practices, which from my perspective makes their conclusions suspect.

Regardless, even if we accept all of these datasets as completely sincere and honestly obtained, they still are in conflict with each other. Under any reasonably scientific analysis, this tells us that the science here is definitely not settled, and that a lot more work needs to be done before anyone can hazard a guess as to what’s going on with the climate.

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Mars rover update: September 20, 2016

11:02 am

Opportunity comes first this time because it actually is more interesting.

Opportunity

For the overall context of Opportunity’s travels at Endeavour Crater, see this post, Opportunity’s future travels on Mars.

Having several choices on where to head, the Opportunity science team this week chose took what looks like the most daring route, heading almost due east towards the floor of Endeavour Crater. In fact, a review of their route and the images that the rover continues to take suggests that the panorama I created last week looked almost due east, not to the southeast as I had guessed. I have amended the most recent overhead traverse image, cropped and reduced below, to show what I now think that panorama was showing.
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How cats conquered the world

8:47 am

Link here. This first large scale study of the DNA of ancient cat remains tracks how felines initially spread through human society in the ancient world.

The article and the researchers appear to make one mistake, however, in questioning whether cats have been domesticated. Anyone who owns a cat can answer that question unequivocally: No! Cats merely agree to live with us, on the condition that we treat them as they demand.

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Saturn’s wonderful rings

11:50 am

Saturn's rings, and the small moons that shape them

Cool image time! The image on the right, reduced to fit here, is a recent Cassini image, taken July 2, 2016, that shows the rings as well as the moon Pan nestled within the ring’s narrow gap

Pan (17 miles or 28 kilometers across, left of center) holds open the Encke gap and shapes the ever-changing ringlets within the gap (some of which can be seen here). In addition to raising waves in the A and B rings, other moons help shape the F ring, the outer edge of the A ring and open the Keeler gap. This view looks toward the sunlit side of the rings from about 8 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 2, 2016.

The image also highlights the incredible and quite magical beauty of Saturn’s rings, which remain to me one of the solar system’s most amazing wonders.

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Scientists make guess about origins of Pluto’s nitrogen sea

10:08 am

Garbage in, garbage out: Scientists have written a computer model that supposedly tells them how Pluto’s thick heart-shaped glacier packed ocean of nitrogen and carbon monoxide formed.

[T]o find out how the glaciers formed in the first place, scientists created models that simulated atmospheric circulation on the dwarf planet for the last 50,000 years (a mere 200 orbits around the sun for Pluto). At the beginning of the simulations, the researchers gave Pluto a planet-wide veneer of nitrogen, carbon monoxide, and methane ices a few millimeters thick; then, the planet’s surface and atmosphere evolved as the icy orb passed through orbit after orbit. If Pluto were a completely smooth sphere, it would have either a permanent swath of nitrogen ice at the equator or seasonal snow caps at its poles. But that’s not what the planet looks like today. When researchers added realistic topography to the model, including the 4-kilometer-deep Sputnik Planum and two other large craters, the basin gradually trapped Pluto’s nitrogen, carbon monoxide, and much of its methane, the researchers report online today in Nature.

While the computer model here can help planetary scientists better understand how Pluto might have evolved, to use it to draw any conclusions about Pluto’s geological history is absurd. Scientist have no idea what Pluto was like 50,000 years ago. Heck, we don’t even know what half the planet looks like now.

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Suspicious climate data manipulation at NASA

1:59 pm

The uncertainty of modern climate science isn’t merely because of the overall complexity of the data and the climate. Though there are numerous factors that contribute to the long term fluctuations of the climate that we do not yet completely understand or can quantify with any precision (the sun, dust, soot, volcanoes, carbon dioxide increase, to name just a few), there is a more tragic uncertainty that global warming scientists at NASA and NOAA have added to the mix, one that is entirely unjustified and harmful to the field of science and the questions that it is trying to answer.

In the case of this post, that tragic uncertainty has to do with sea level rise and the “adjustments,” without explanation, that NASA is making to its sea level data. Below is a graph taken from the link, showing the changes that have been made to published data from 1982 in order to eliminate a long period of almost no sea level rise from the mid 1950s through 1980.
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Thirty ton meteorite excavated in Argentina

9:10 am

In what is one of the largest asteroid chunks ever found on Earth, an excavation team from a local astronomy club this week excavated a thirty ton iron-nickel meteorite from the ground.

Dubbed Gancedo after a nearby town, it isn’t a record-holder, but it sure is big. What I found interesting from the article, however, is this:

Gancedo’s fall to Earth occurred between 4,000 and 6,000 years ago. Locals knew of the fall for centuries, even making iron tools from meteorites found in the strewnfield. In the 16th century, the Spanish became interested in stories of a piece of iron that fell from the sky, and in 1774 don Bartolomé Francsico de Maguna led an expedition that came across a mass of iron, referred to as Mesón de Fierro (“Table of Iron” in Spanish). Another 1,400-pound fragment from Campo del Cielo named Otumpa now resides at the British Museum in London. With more than 100 tons of meteorite recovered, Campo del Cielo is the top producer in terms of pure meteorite mass worldwide.

The Campo del Cielo strewnfield extends over an ellipse 3 km wide by 19 km long over an area northwest of Buenos Aires, and meteorites found here have a polycrystalline coarse octahedrite composition characteristic of iron-nickel meteorites. They are also unusually pure even among iron-nickel meteorites, consisting of 93% iron. Most of the remaining 7% is nickel, and less than 1% are trace elements.

The evidence here is that a very dense asteroid, weighing a minimum of 100 tons but probably several times that, smashed into the Earth about five thousand years ago. Yet, all life on Earth was not wiped out, as is repeatedly suggested might happen whenever a similarly sized asteroid zips close past the Earth. In fact, there is no evidence this impact had any significant global environmental effects.

Remember this the next time another asteroid of similar size zips past the Earth and the media doom-sayers begin to sing their siren song again.

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UN Secretary-General declares climate change debate ‘over’

10:57 am

The certainty of politics: In a newspaper interview on Thursday UN Secretary-General Ban Ki-moon declared, without doubt, that the scientific debate on human-caused global warming “is over”.

U.N. Secretary-General Ban Ki-moon said Thursday that his greatest achievement at the helm of the world’s biggest international organization was last year’s climate change accord in Paris, and he expressed open frustration that Republicans in the U.S. continue to obstruct President Obama and to politicize the subject. “The debate on science and the debate on politics as far as climate change is concerned is over,” Mr. Ban told The Washington Times in an exclusive interview. “Still, the Republican Party, they are not convinced.

“There should be no political consideration on this,” he said. “There should be no room for politics to get involved.” [emphasis mine]

I am so glad that this politician, not a scientist, knows so much about the climate field that he can dictate the future research of scientists. I am so glad that this politician, not a scientist, thinks he has the ability to tell skeptics to shut up. And I am so glad that this politician, not a scientist, can demand that skeptics shut up because he wants to keep politics out of science. (Note the irony and hypocrisy here.)

I find it most interesting that whenever anyone raises questions about the theory of human-caused global warming, the response by its advocates is almost never to discuss the actual data, but to tell the questioners to shut up, and to insist the debate is settled, even though the very existence of those questioners proves it is not.

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Rosetta’s last days

10:36 am

The Rosetta team has released a detailed description of what will be happening in the last two weeks of the spacecraft’s mission, leading up to its landing on the comet’s surface on September 30.

Their description of the difficulty of planning maneuvers based on the complex asymmetrical gravitational field of the two-lobed comet nucleus is especially interesting.

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Saturn in all its glory

3:31 pm

Saturn

Cool image time. The Cassini science team have released a beautiful full-color image of Saturn, shown cropped on the right, as well as a movie, both produced from images taken in April.

This view shows Saturn’s northern hemisphere in 2016, as that part of the planet nears its northern hemisphere summer solstice in May 2017. Saturn’s year is nearly 30 Earth years long, and during its long time there, Cassini has observed winter and spring in the north, and summer and fall in the south. The spacecraft will complete its mission just after northern summer solstice, having observed long-term changes in the planet’s winds, temperatures, clouds and chemistry.

Cassini scanned across the planet and its rings on April 25, 2016, capturing three sets of red, green and blue images to cover this entire scene showing the planet and the main rings. The images were obtained using Cassini’s wide-angle camera at a distance of approximately 1.9 million miles (3 million kilometers) from Saturn and at an elevation of about 30 degrees above the ring plane. The view looks toward the sunlit side of the rings from a sun-Saturn-spacecraft angle, or phase angle, of 55 degrees. Image scale on Saturn is about 111 miles (178 kilometers) per pixel.

The exposures used to make this mosaic were obtained just prior to the beginning of a 44-hour movie sequence.

The only real tragedy here is that the Cassini mission is ending soon. When it does, it will be decades, at a minimum, before we have another spacecraft in orbit around Saturn and capable of giving us this view.

Update: NASA today issued a press release detailing what will happen during Cassini’s final year at Saturn, including 22 plunges between Saturn and its rings!

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New evidence of lakes and streams in Mars’ recent past

1:26 pm

Using data from three different orbiters scientists have mapped out a region of lakes and streams on Mars that appear to have contained liquid water a billion years after the red planet is believed to have dried up.

To bracket the time period when the fresh shallow valleys in Arabia Terra formed, scientists started with age estimates for 22 impact craters in the area. They assessed whether or not the valleys carved into the blankets of surrounding debris ejected from the craters, as an indicator of whether the valleys are older or younger than the craters. They concluded that this fairly wet period on Mars likely occurred between two and three billion years ago, long after it is generally thought that most of Mars’ original atmosphere had been lost and most of the remaining water on the planet had frozen.

The characteristics of the valleys support the interpretation that the climate was cold: “The rate at which water flowed through these valleys is consistent with runoff from melting snow,” Wilson said, “These weren’t rushing rivers. They have simple drainage patterns and did not form deep or complex systems like the ancient valley networks from early Mars.”

This region, Arabia Terra, is the same area where scientists have found fossilized rivers.

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Hubble captures on-going comet break-up

10:47 am

animation of comet debris

Cool image time! The animation to the right, taken over three days by the Hubble Space Telescope, cropped and reduced to fit here, shows the debris flying away from Comet 332P/Ikeya-Murakami. It also shows a new piece of debris close to the comet on the lower left.

The research team calculated that the comet probably shed material over several months, between October and December 2015. Jewitt suggests that even some of the ejected pieces have themselves fallen to bits in a kind of cascading fragmentation. “Our analysis shows that the smaller fragments are not as abundant as one might expect based on the number of bigger chunks,” he said. “This is suggestive that they’re being depleted even in the few months since they were launched from the primary body. We think these little guys have a short lifetime.”

Hubble’s sharp vision also spied a chunk of material close to the comet, which may be the first salvo of another outburst. The remnant from still another flare-up, which may have occurred in 2012, is also visible. The fragment may be as large as Comet 332P, suggesting the comet split in two. But the icy remnant wasn’t spotted until Dec. 31, 2015, by the Pan-STARRS (Panoramic Survey Telescope and Rapid Response System) telescope in Hawaii, in work supported by the Near-Earth Object Observations program in NASA’s Planetary Defense Coordination Office. That discovery prompted Jewitt and colleagues to request Hubble time to look at the comet in detail. Around the same time, astronomers around the world began to notice a cloudy patch of material near the comet – which Hubble later resolved into the 25 pieces.

The scientists think they actually “may be seeing a comet fragmenting itself into oblivion.”

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Four different research papers this year find no evidence linking human activity to sea level rise

10:18 am

The uncertainty of science: Despite the claims that human-caused global warming is causing the icecaps to melt and the sea to rise, four different research papers this year have found no “observable” evidence linking human activity to sea level rise.

“It is widely assumed that sea levels have been rising in recent decades largely in response to anthropogenic global warming,” Kenneth Richard writes at NoTricksZone. “However, due to the inherently large contribution of natural oscillatory influences on sea level fluctuations, this assumption lacks substantiation…. Scientists who have recently attempted to detect an anthropogenic signal in regional sea level rise trends have had to admit that there is ‘no observable sea-level effect of anthropogenic global warming’,” Richard points out, listing four peer-reviewed studies published this year that have all come to the same conclusion.

Does this prove that the rise in sea levels is not influenced by human activity (or “an anthropogenic signal” to use the jargon of these scientists)? Absolutely not. What it does show is that the science of climate change remains completely uncertain, and that it is very possible that all of the sea level rise we see has nothing to do with human activity, something that many climate scientists have recognized for decades. We are still coming out of the last ice age, and these scientists recognize that much if not all of the sea level rise we see can be attributable to this fact.

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Charon’s red polar region explained?

12:43 pm

Scientists, using data from New Horizons as well as new computer models, think they have come up with an explanation for the red polar region of Pluto’s moon Charon.

As they detail this week in the international scientific journal Nature, Charon’s polar coloring comes from Pluto itself – as methane gas that escapes from Pluto’s atmosphere and becomes “trapped” by the moon’s gravity and freezes to the cold, icy surface at Charon’s pole. This is followed by chemical processing by ultraviolet light from the sun that transforms the methane into heavier hydrocarbons and eventually into reddish organic materials called tholins.

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