Tag: science

Juno flight plan at Jupiter revised

10:16 am

In preparation for its arrival in orbit around Jupiter in about a year, engineers for the unmanned probe Juno have revised their planned orbital maneuvers.

Following a detailed analysis by the Juno team, NASA recently approved changes to the mission’s flight plan at Jupiter. Instead of taking 11 days to orbit the planet, Juno will now complete one revolution every 14 days. The difference in orbit period will be accomplished by having Juno execute a slightly shorter engine burn than originally planned.

The revised cadence will allow Juno to build maps of the planet’s magnetic and gravity fields in a way that will provide a global look at the planet earlier in the mission than the original plan. Over successive orbits, Juno will build a virtual web around Jupiter, making its gravity and magnetic field maps as it passes over different longitudes from north to south. The original plan would have required 15 orbits to map these forces globally, with 15 more orbits filling in gaps to make the map complete. In the revised plan, Juno will get very basic mapping coverage in just eight orbits. A new level of detail will be added with each successive doubling of the number, at 16 and 32 orbits.

The change will extend the official mission from 15 to 20 months, though I expect that even this will be extended if the spacecraft’s fuel holds out.

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New radio communications from Philae

9:35 am

On July 9 Philae successfully transmitted data to Rosetta for the first time in more than two weeks.

Although the connection failed repeatedly after that, it remained completely stable for those 12 minutes. “This sign of life from Philae proves to us that at least one of the lander’s communication units remains operational and receives our commands,” said Koen Geurts, a member of the lander control team at DLR Cologne.

The mood had been mixed over the last few days; Philae had not communicated with the team in the DLR Lander Control Center (LCC) since 24 June 2015. After an initial test command to turn on the power to CONSERT on 5 July 2015, the lander did not respond. Philae’s team began to wonder if the lander had survived on Comet 67P/Churyumov-Gerasimenko.

The intermittent nature of Philae’s attempts at communication are puzzling. Normally, they either would have communications or they would not. For good communications to break off like this repeatedly is puzzling. It is almost as if there is a loose wire causing communications to go on and off, which seems an unlikely explanation for this problem.

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New image of Pluto and Charon

12:02 am

Pluto and Charon

The New Horizons science team today released a new image showing both Pluto and Charon, and not unexpectedly, they are very different from each other.

A high-contrast array of bright and dark features covers Pluto’s surface, while on Charon, only a dark polar region interrupts a generally more uniform light gray terrain. The reddish materials that color Pluto are absent on Charon. Pluto has a significant atmosphere; Charon does not. On Pluto, exotic ices like frozen nitrogen, methane, and carbon monoxide have been found, while Charon’s surface is made of frozen water and ammonia compounds. The interior of Pluto is mostly rock, while Charon contains equal measures of rock and water ice. “These two objects have been together for billions of years, in the same orbit, but they are totally different,” said Principal Investigator Alan Stern of the Southwest Research Institute (SwRI), Boulder, Colorado.

For a half century, since the first probes left Earth to visit other worlds, the one consistent axiom we have learned from every mission is that no two objects are going to be alike, and that every object out there is going to be incredibly unique. Pluto and Charon, in finishing the human race’s first inventory of the solar system, prove this axiom once again.

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A bullseye in space

11:18 am

Cool image time! The science team of the Swift space telescope has released a movie compiled from X-ray images taken of the first outburst from black hole V404 Cygni in 26 years. [link fixed!]

Astronomers say the rings result from an “echo” of X-ray light. The black hole’s flares emit X-rays in all directions. Dust layers reflect some of these X-rays back to us, but the light travels a longer distance and reaches us slightly later than light traveling a more direct path. The time delay creates the light echo, forming rings that expand with time.

Detailed analysis of the expanding rings shows that they all originate from a large flare that occurred on June 26 at 1:40 p.m. EDT. There are multiple rings because there are multiple reflecting dust layers between 4,000 and 7,000 light-years away from us. Regular monitoring of the rings and how they change as the eruption continues will allow astronomers to better understand their nature.

V404 Cygni is located about 8,000 light-years away. Every couple of decades the black hole fires up in an outburst of high-energy light. Its previous eruption ended in 1989.

The animation below the fold is a smaller resolution version of the movie, showing the rings as they expand outward.
» Read more

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A new double dynamo theory to explain the Sun’s solar cycle

10:45 am

A team of solar scientists have proposed a new theory that they think explains the ebb and flow of the Sun’s eleven year solar cycle, and if right can explain the periodic occurrence of grand minimums where there are essentially no sunspots for decades, such as the Maunder Minimum in the 1600s.

The theory proposes that the Sun has two different dynamos that produce different magnetic waves in its interior. Like waves that can either cancel each other out or combine for more power, these two dynamos do the same over time and thus effect the Sun’s sunspot/solar cycle.

“We found magnetic wave components appearing in pairs, originating in two different layers in the Sun’s interior. They both have a frequency of approximately 11 years, although this frequency is slightly different, and they are offset in time. Over the cycle, the waves fluctuate between the northern and southern hemispheres of the Sun. Combining both waves together and comparing to real data for the current solar cycle, we found that our predictions showed an accuracy of 97%,” said Zharkova.

Zharkova and her colleagues derived their model using a technique called ‘principal component analysis’ of the magnetic field observations from the Wilcox Solar Observatory in California. They examined three solar cycles-worth of magnetic field activity, covering the period from 1976-2008. In addition, they compared their predictions to average sunspot numbers, another strong marker of solar activity. All the predictions and observations were closely matched.

Looking ahead to the next solar cycles, the model predicts that the pair of waves become increasingly offset during Cycle 25, which peaks in 2022. During Cycle 26, which covers the decade from 2030-2040, the two waves will become exactly out of synch and this will cause a significant reduction in solar activity.

“In cycle 26, the two waves exactly mirror each other – peaking at the same time but in opposite hemispheres of the Sun. Their interaction will be disruptive, or they will nearly cancel each other. We predict that this will lead to the properties of a ‘Maunder minimum’,” said Zharkova. “Effectively, when the waves are approximately in phase, they can show strong interaction, or resonance, and we have strong solar activity. When they are out of phase, we have solar minimums. When there is full phase separation, we have the conditions last seen during the Maunder minimum, 370 years ago.”

And on this same subject, last week NOAA posted its monthly update of the solar cycle, showing the Sun’s sunspot activity in June. As I have done every month since 2010, I am posting it here, below the fold, with annotations to give it context.
» Read more

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Watch Opportunity’s full journey on Mars, in 8 minutes

9:54 am

The science team for the Mars rover Opportunity have released an 8-minute movie compiled from the rover’s hazard-avoidance cameras. Enjoy!

One comment: There is a long stretch of territory south of Albuquerque, New Mexico called Jornada de Muerto, which means “Journey of Death” in English. It gets its name from its lack of water or life. This video makes that stretch of land look like a water park, strongly highlighting the utter barrenness of the Martian surface.

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Best image yet of Pluto

9:29 am

Pluto

Very cool image time! The New Horizons science team today released [link fixed] their best image yet of Pluto, taken on July 7 immediately following the spacecraft’s recovery from safe mode.

This view is centered roughly on the area that will be seen close-up during New Horizons’ July 14 closest approach. This side of Pluto is dominated by three broad regions of varying brightness. Most prominent are an elongated dark feature at the equator, informally known as “the whale,” and a large heart-shaped bright area measuring some 1,200 miles (2,000 kilometers) across on the right. Above those features is a polar region that is intermediate in brightness.

For the first time these features look like actual surface areas on a planet, not fuzzy blobs. We are still seeing Pluto like we saw all planets prior to the space age, but at least now we know what we are looking at.

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Dance of the stars

8:51 am

Astronomers have found a stellar system made up of five stars, two binary systems orbiting each other, with a fifth star orbiting one of the stars in one of the binaries.

Co-author Dr Markus Lohr, from the Open University, told BBC News that these contact binaries were stars that orbit so closely they share an outer atmosphere. The other star pair – a detached binary – has a separation distance of some three million km. The two binaries orbit in the same plane at a distance of 21 billion km.

Follow-up observations of different wavelengths of light coming from the star system uncovered a fifth star, which is linked to the detached binary star. “This is a truly exotic star system. In principle there’s no reason why it couldn’t have planets in orbit around each of the pairs of stars. Any inhabitants would have a sky that would put the makers of Star Wars to shame,” Dr. Lohr said. “There could sometimes be no fewer than five Suns of different brightnesses lighting up the landscape.”

Dr. Lohr is being a bit extravagant. Though planets are a possibility here, I suspect it very unlikely that they are habitable.

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A New Horizons map of Pluto

11:54 pm

New Horizons map of Pluto

Cool image time! The New Horizons science team today released their best global map of Pluto, as seen so far.

The center of the map shows the area that New Horizons will see close-up during the fly-by.

The elongated dark area informally known as “the whale,” along the equator on the left side of the map, is one of the darkest regions visible to New Horizons. It measures some 1,860 miles (3,000 kilometers) in length. Directly to the right of the whale’s “snout” is the brightest region visible on the planet, which is roughly 990 miles (1,600 kilometers) across. This may be a region where relatively fresh deposits of frost—perhaps including frozen methane, nitrogen and/or carbon monoxide—form a bright coating.

Continuing to the right, along the equator, we see the four mysterious dark spots that have so intrigued the world, each of which is hundreds of miles across. Meanwhile, the whale’s “tail,” at the left end of the dark feature, cradles a bright donut-shaped feature about 200 miles (350 kilometers) across. At first glance it resembles circular features seen elsewhere in the solar system, from impact craters to volcanoes. But scientists are holding off on making any interpretation of this and other features on Pluto until more detailed images are in hand.

Some of these features will not be resolved much clearer than this, as Pluto’s day is six Earth days long, and will thus not be visible any longer to the spacecraft during its last week approach. In addition, much of the southern hemisphere will also not be imaged at all, as the planet’s inclination puts much of that hemisphere out of view entirely.

Nonetheless, we will see a great deal that has never been seen before. Stay tuned!

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Brainstorm – the world’s smartest mouse

6:01 pm

An evening pause: You might say this a variation on a Rube Goldberg device, except that instead of gravity running the show it is a mouse.

Hat tip Phill Oltmann.

Readers: I am always looking for tips for my evening pauses. If you see a video you think might fit, make a comment here mentioning that you have something, but don’t post the link. I will email you to get it from you.

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Dawn recovers from safe mode

9:17 am

Spot 1

Beginning on June 30 Dawn experienced an as yet unexplained “anomaly” that put it into safe mode for several days.

According to JPL, engineers have uploaded “configuration changes” that solved the problem, and the spacecraft has returned to normal operations, continuing its second mapping orbit of Ceres. From this position they are gathering wide angle images of the entire planet, from which they will construct a detailed global map to be used as a baseline during later more detailed close-up orbits. For example, they released this very nice image today of what is called “Spot 1”, shown on the right. I have cropped it to focus on the spot itself. Looks almost like scattered snow on the surface, doesn’t it?

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Obamacare continues to cause health insurance premiums to skyrocket

1:06 pm

Finding out what’s in it: Health insurance companies are now requesting (and getting) rate increases from 23 to 54 percent due to the increased costs imposed by Obamacare.

Blue Cross and Blue Shield plans — market leaders in many states — are seeking rate increases that average 23 percent in Illinois, 25 percent in North Carolina, 31 percent in Oklahoma, 36 percent in Tennessee and 54 percent in Minnesota, according to documents posted online by the federal government and state insurance commissioners and interviews with insurance executives.

The Oregon insurance commissioner, Laura N. Cali, has just approved 2016 rate increases for companies that cover more than 220,000 people. Moda Health Plan, which has the largest enrollment in the state, received a 25 percent increase, and the second-largest plan, LifeWise, received a 33 percent increase.

At the same time, many insurance companies are merging or leaving the market because of the law makes profitability impossible.

Obviously, we must all then vote for Democrats so they can use their brilliance (demostrated so clearly with Obamacare) to solve this problem by nationalizing healthcare.

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New Horizons temporarily loses contact with Earth

9:38 am

Engineers lost contact with New Horizons for an hour and twenty-one minutes on Saturday.

Engineers have since begun talking with the probe again, but NASA says it will take up to several days to get New Horizons back to normal. In the meantime, the US$700-million spacecraft is not recording science data. It is just 11 million kilometres from Pluto, and closing in fast.

Communication issues are exacerbated by the fact that it takes four and a half hours to send a signal, traveling at light speed, across the nearly 4.8 billion kilometres to the spacecraft — and four and a half hours back. In that elapsed time, the Earth has rotated so much that mission controllers must switch from one to another of the three deep-space antennas that communicate with spacecraft: in Goldstone, California; Canberra; and Madrid.

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The jets on Comet 67P/C-G come from its sinkholes

10:18 am

More on the comet sinkholes! New data from Rosetta has now confirmed that some of the plumes or jets that the spacecraft has seen emanating from Comet 67P/C-G come directly from the sinkholes that they have discovered on the nucleus.

In a study reported today in the science journal Nature, 18 quasi-circular pits have been identified in the northern hemisphere of the comet, some of which are the source of continuing activity. The pits are a few tens to a few hundreds of metres in diameter and extend up to 210 m below the surface to a smooth dust-covered floor. Material is seen to be streaming from the most active pits. “We see jets arising from the fractured areas of the walls inside the pits. These fractures mean that volatiles trapped under the surface can be warmed more easily and subsequently escape into space,” says Jean-Baptiste Vincent from the Max Planck Institute for Solar System Research, lead author of the study.

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TMT protesters complain about road closure

9:59 am

The leader of the protest that is opposing the construction of the Thirty Meter Telescope (TMT) is now complaining about the road closure imposed by Hawaii’s government that is preventing him and his followers from returning to the mountain.

“The telescope employees have been able to access the mountain every single day to go up and come back down and even we as protectors of the mountain have been given daily access to conduct pule and religious practices on the mountain,” said Kahookahi Kanuha, a member of Ku Kia’i Mauna, which hopes to keep the telescope from being built. “So, if they do deem it unsafe, it is quite irresponsible of them to allow other individuals up the mountain.”

So let me get this straight: He thinks it is wrong for the people who own or lease the mountain — who have legal right to control access — to block the protesters, but he sees nothing wrong with him going there — trespassing — and blocking access to others. What a hypocrite.

This article proves that my analysis from Tuesday is correct. The government has shut the road mainly to quietly get the protesters out of the way and let things cool down. When construction resumes, I guarantee that road access will restricted to prevent the protesters from returning and blocking the road. (Update: The quotes here from the state’s attorney general provide even further confirmation that the state will not allow protests to obstruct future access to construction crews.)

One other note: The author of the first article above uses the typical dishonest mainstream media technique of only quoting one protester, the activist leader, while claiming that “protesters” are objecting. The data in the article, however, does not document this spin. As far as I can tell, the only one complaining about the road closure is this one guy.

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What we will and will not see during the Pluto fly-by

9:32 am

Pluto's two hemispheres

The images above, released today by the New Horizons’ science team, provide the best global view so far of Pluto’s two hemispheres. I have cropped and rearranged the original to focus on Pluto.

The images illustrate some basic new knowledge about the planet. For one, scientists have now identified the planet’s poles, based upon its rotation. While scientists had had a very rough vague idea of Pluto’s rotation and inclination beforehand, they have now pinned it down pretty precisely.

The images also show the planet’s most striking and unique features, though not with enough resolution to tell us what they are.

New color images from NASA’s New Horizons spacecraft show two very different faces of the mysterious dwarf planet, one with a series of intriguing spots along the equator that are evenly spaced. Each of the spots is about 300 miles in diameter, with a surface area that’s roughly the size of the state of Missouri.

Scientists have yet to see anything quite like the dark spots; their presence has piqued the interest of the New Horizons science team, due to the remarkable consistency in their spacing and size. While the origin of the spots is a mystery for now, the answer may be revealed as the spacecraft continues its approach to the mysterious dwarf planet. “It’s a real puzzle—we don’t know what the spots are, and we can’t wait to find out,” said New Horizons principal investigator Alan Stern of the Southwest Research Institute, Boulder. “Also puzzling is the longstanding and dramatic difference in the colors and appearance of Pluto compared to its darker and grayer moon Charon.”

This image release also shows us what we will and will not see during the fly-by. The image on the left is the “encounter hemisphere.” This is the hemisphere that will be in view during New Horizons’ July 14 fly-by. We shall get very nice high resolutions of much of this hemisphere.

The other hemisphere, however, will not be facing us during the fly-by. Unless that can get some high resolution images before it rotates out of view, the row of large dark spots at the equator will remain a mystery.

The images also suggest that, because of Pluto’s tilt, much of the southern hemisphere is not going to be seen at all. It will remain an additional mystery for the many decades that are going to pass before another spacecraft finally returns to this distant place.

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Active sinkholes found on Comet 67P/C-G

11:00 am

pits on Comet 67P/C-G

Cool image time! Using Rosetta’s high resolution camera scientists have located a number of active pits similar to sinkholes on Earth on Comet 67P/C-G.

Based on the Rosetta observations, the team has proposed a model for the formation of these sinkholes. A source of heat beneath the comet’s surface causes ices (primarily water, carbon monoxide and carbon dioxide) to sublimate. The voids created by the loss of these ice chunks eventually grow large enough that their ceilings collapse under their own weight, giving rise to the deep, steep-sided circular pits seen on the surface of comet 67P/Churyumov-Gerasimenko.

The collapse exposes comet ices to sunlight for the first time, which causes the ice chunks to begin sublimating immediately. These deeper pits are therefore thought to be relatively young. Their shallower counterparts, on the other hand, are most likely older sinkholes with more thoroughly eroded sidewalls and bottoms that have been filled in by dust and ice chunks.

Essentially, they have found that decay of the comet’s nucleus has been mostly gentle and steady, rather than explosive, punctuated with sudden abrupt events.

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New Horizons gets closer

11:30 pm

Pluto and Charon

Cool image time! Even as the engineers successfully completed last night their last course correction engine burn, the New Horizons science team released an image showing both Pluto and Charon.

The 23-second thruster burst was the third and final planned targeting maneuver of New Horizons’ approach phase to Pluto; it was also the smallest of the nine course corrections since New Horizons launched in January 2006. It bumped the spacecraft’s velocity by just 27 centimeters per second – about one-half mile per hour – slightly adjusting its arrival time and position at a flyby close-approach target point approximately 7,750 miles (12,500 kilometers) above Pluto’s surface.

The image, which I have cropped to focus on the planets, is still somewhat fuzzy, though it also shows the increasing sharpness as the spacecraft gets closer.

Only two weeks to go!

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Another Dawn image of some of Ceres’ bright spots

10:37 am

The double bright spot, not over-exposed

Cool image time! As part JPL’s regular release of images from Dawn, one image of Ceres’ bright double spots was purposely not over-exposed. Thus, the surface is almost black (as it really looks), while the small cluster of spots stands out brightly but with some additional detail. (If you download the full image and use a graphics program to brighten it you will see that this is the double bright spot located inside a large crater.)

I have cropped and enlarged the original image to focus on the double spot. As you can see the brightest spot has a mottled look, almost like we are looking down at a snow-capped peak.

Though the leading theory remains that this is ice, this theory has not been confirmed yet. Make no assumptions or you may discover you are wrong.

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An update on Rosetta’s effort to re-establish contact with Philae

8:47 am

This update describes the status of the effort by the Rosetta science team to re-establish a stable communications channel with the Philae lander on the surface of Comet 67P/C-G.

Confirmed contacts between Rosetta and Philae have been made on 13, 14, 19, 20, 21, 23, and 24 June, but were intermittent during those contact periods. For example, the contact on 19 June was stable but split into two short periods of two minutes each. Conversely, the contact on 24 June started at 17:20 UT (on board Rosetta) and ran for 20 minutes, but the quality of the link was very patchy and only about 80 packets of telemetry were received. Prior to this, on Tuesday, 23 June, there was a 20-second contact, but no stable link was established and consequently no telemetry data were received.

There are many reasons why the contacts have been so intermittent, much of it related to Philae’s position on the surface. To improve things, they are carefully adjusting Rosetta’s position relative to the comet while avoiding placing the spacecraft in a position where the coma’s dust will cause problems.

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Black hole awakes after 26 years

10:44 am

For the first time since 1989, the black hole in V404 Cygni, a system comprising a black hole and a star, has reawakened, suddenly emitting high energy outbursts beginning on June 15.

First signs of renewed activity in V404 Cygni were spotted by the Burst Alert Telescope on NASA’s Swift satellite, detecting a sudden burst of gamma rays, and then triggering observations with its X-ray telescope. Soon after, MAXI (Monitor of All-sky X-ray Image), part of the Japanese Experiment Module on the International Space Station, observed an X-ray flare from the same patch of the sky.

These first detections triggered a massive campaign of observations from ground-based telescopes and from space-based observatories, to monitor V404 Cygni at many different wavelengths across the electromagnetic spectrum.

The outbursts are probably occurring because the black hole is gobbling up material that has fallen into it.

While the 1989 outburst helped astronomers gain their first understand of the behavior of a black hole in a star system, this outburst will help them understand how such systems evolve and change over time.

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Finding Pluto is really New Horizon’s biggest problem

9:59 am

As New Horizons speeds towards its planned fly-by of Pluto on July 14, the biggest problem faced by its engineers is making sure the spacecraft actually finds and photographs the planet.

Because astronomers discovered the dwarf planet in 1930, they have seen only part of its 248-year path around the Sun, and they don’t know exactly where Pluto is. And New Horizons is so far from Earth that it takes 9 hours to send and receive a signal, making the spacecraft hard to direct in real time. “Everything is pushed to the extreme,” says Bobby Williams, an engineer at KinetX Aerospace in Simi Valley, California, who heads the mission’s navigation team.

This fact, which has not been mentioned previously as far as I remember, suggests that there is a good chance that New Horizons might fly through its planned window and aim its cameras at the wrong spot in the sky, missing Pluto entirely. It also explains partly why the images released so far have been so fuzzy: They are focused mostly on doing navigation work, and are taking wide angle shots to make sure they catch Pluto in their picture frame. Zooming in too close might actually miss Pluto as they don’t exactly know where it is.

All this only makes the July 14th fly-by even more exciting. Let us hope they do due diligence and get the pictures we all want!

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Hawaii governor halts TMT construction again

9:30 am

In a very vague statement the governor of Hawaii has once again stopped construction of the Thirty Meter Telescope (TMT) while he reassesses the situation after protesters yesterday blocked the road to the mountain summit with boulders.

“We are disappointed and concerned that large boulders were found in the roadway leading to the summit of Mauna Kea,” McCartney said in the statement. “This action is a serious and significant safety hazard and could put people at risk. “Because of this, we are making an assessment to determine how to proceed,” he said. “We will be working to clear the roadway tomorrow. Therefore, construction is on hold until further notice.”

The statement implies that he is trying to figure out a way to prevent the protesters from blocking the road, without causing more conflict. I instead suspect he sympathies with the protesters, and is looking for a way to stop construction, which he legally cannot do.

If the road is not reopened by the end of this week and construction is still blocked, I think the TMT managers, as well as the operators of the other telescopes on the mountain, should seriously consider moving from Hawaii. I also repeat that a boycott of Hawaiian tourism might also be appropriate now. This is what these nativist activists want, no more outsiders. We should give them what they want.

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The icy patches on Comet 67P/C-G

8:48 am

Data from Rosetta’s high resolution camera have identified more than a hundred small patches of ice on the surface of Comet 67P/C-G.

Some of these bright features are found in clusters, while others appear isolated, and when observed at high resolution, many of them appear to be boulders displaying bright patches on their surfaces.

The clusters of bright features, comprising a few tens of metre-sized boulders spread over several tens of metres, are typically found in debris fields at the base of cliffs. They are most likely the result of recent erosion or collapse of the cliff wall revealing fresher material from below the dust-covered surface.

By contrast, some of the isolated bright objects are found in regions without any apparent relation to the surrounding terrain. These are thought to be objects lifted up from elsewhere on the comet during a period of cometary activity, but with insufficient velocity to escape the gravitational pull of the comet completely.

Most of the images from Rosetta’s high resolution camera have been held back so that the project scientists could publish their papers from the data. This release is in conjunction with one of those papers [pdf].

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New images of Pluto

12:06 pm

Latest Pluto images

Cool image time! The two images on the right, taken on June 18 and June 15 respectively, — cropped from a larger collection — show Pluto’s two hemispheres, as best as New Horizons can at the moment resolve them.

While still as fuzzy as pre-space age planetary images, the pictures when compared with earlier images of the same hemispheres now clearly show several consistent features.

Things can only get better. Stay tuned!

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