Tag: science

Hayabusa-2 will do two touchdown rehearsals prior to landing in January

9:37 am

In order to test whether they can bring Hayabusa-2 down to the surface within a circle only 20 meters (65 feet) across (the largest smooth landing area they have found so far on Ryugu), their engineering team has decided to first do two more touchdown rehearsals in October.

In the area where the spacecraft will touchdown, it is dangerous to have boulders with a height greater than about 50cm. Since the length of the sampler horn is about 1m and the spacecraft will be to be slightly inclined during the touchdown, there is a possibility that if a boulder with a height above about 50cm is present, it will strike the main body of the spacecraft or the solar panels. Viewed from the position in Figure 2, there is no boulder larger than 50cm in the area L08-B. L08-B is the widest part within all the candidate sites without a boulder larger than 50cm.

The difficulty is that area L08-B is only about 20m in diameter. Originally, it was assumed that a safe region for touchdown would be a flat area with a radius of about 50m (100m in diameter). This has now become a radius of just 10m; a fairly severe constraint. On the other hand, during the descent to an altitude of about 50m during the MINERVA-II1 and MASCOT separation operations, we were able to confirm that the spacecraft can be guided within a position accuracy of about 10m for a height 50m above the surface of Ryugu (Figure 3). This is a promising feature for touchdown.

Although the spacecraft can be controlled with a position error of 10m at an altitude down to 50m, there remains the question of whether this accuracy can be retained as the spacecraft descends to the surface. This must be confirmed before touchdown operations. Therefore, the touchdown itself will be postponed until next year, during which time we will have two touchdown rehearsals; TD1-R1-A and TD1-R3.

After the rehearsals in October they must wait until January to do the landing because in November and December the sun will be in-between the Earth and the spacecraft, making operations more difficult. They want to also use this time to review the results of the rehearsals to better prepare for the January landing.

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Curiosity sends down images for the first time in weeks

9:28 am

Good news! For the first time since September 15 Curiosity has sent back images.

The last raw images were received on Sol 2171, equivalent to September 15. Today’s images (Sol 2199) from the front and rear hazard cameras and the two navigation cameras suggest that the engineers have solved the computer issues that prevented the rover from sending its science data to Earth.

No press release has yet been released, but I suspect we shall see something shortly.

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Chandra goes into safe mode

11:43 pm

When it rains it pours: The Chandra X-ray Observatory went into into safe mode on October 10 for reasons that are either not yet understood or have not yet been revealed.

Chandra, Spitzer, and Hubble are the three remaining of the original four great observatories proposed in the late 1980s, with the Compton Gamma-Ray Observatory the fourth. Compton was de-orbited in 2000. Spitzer’s infrared observational capabilities became limited when its cryogenic cooling gas became exhaused in 2009.

Hubble and now Chandra are both in safe mode, leaving astronomy badly crippled.

This situation is actually the fault of the astronomical community, which in the early 2000s put all its money behind the James Webb Space Telescope, leaving little for the construction of replacement space telescopes for either Hubble or Chandra. In addition, the astronomical community has continued to put is money behind similar big, expensive, and giant projects like Webb, pushing for WFIRST with its 2011 decadal survey. Like Webb, WFIRST will cost billions and take almost a decade to build and launch, assuming there are no delays.

Meanwhile, the workhorses in orbit are failing one by one.

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Update on Hubble: no real news

2:15 pm

NASA today released an update on the effort to bring the Hubble Space Telescope out of safe mode and back to full operation.

The only new information they really provide is what they will do, depending on whether they can fix the back up gyroscope or not.

If the team is successful in solving the problem, Hubble will return to normal, three-gyro operations. If it is not, the spacecraft will be configured for one-gyro operations, which will still provide excellent science well into the 2020s, enabling it to work alongside the James Webb Space Telescope and continue groundbreaking science.

In other words, if they cannot find a way to get this third gyro functioning properly, they will shut down one of the two remaining working gyros so that it can operate as a backup, and operate the telescope on one gyroscope.

I find the last section of the quote above very amusing, in a dark sort of way. Not only does NASA rationalize the sad loss of Hubble’s ability to take sharp images, it tries to rationalize the decade-long delays it has experienced building the James Webb Space Telescope. Webb was supposed to have been launched in 2011. It should have been up there already, working alongside Hubble for the past seven years.

Now, the best we can hope for is that Webb will finally reach space while Hubble is still functioning, in a crippled condition. I would not be surprised however if Webb is further delayed, and Hubble is gone before it gets into space.

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MASCOT’s journey on Ryugu

8:31 am

MASCOT's journey on Ryugu

MASCOT’s German science team has released a summary of the lander/hopper’s results and seventeen hour journey across the surface of the asteroid Ryugu. The image on the right, reduced and cropped to post here, shows the spacecraft approach, landing, and numerous hops across the surface. If you click on the image you can see the full high resolution image.

Having reconstructed the events that took place on asteroid Ryugu, the scientists are now busy analysing the first results from the acquired data and images. “What we saw from a distance already gave us an idea of what it might look like on the surface,” reports Ralf Jaumann from the DLR Institute of Planetary Research and scientific director of the MASCOT mission. “In fact, it is even crazier on the surface than expected. Everything is covered in rough blocks and strewn with boulders. How compact these blocks are and what they are composed of, we still do not know. But what was most surprising was that large accumulations of fine material are nowhere to be found – and we did not expect that. We have to investigate this in the next few weeks, because the cosmic weathering would actually have had to produce fine material,” continues Jaumann.

The spacecraft apparently bounced eight times after first contact, then executed three hops. The rubble pile nature that is observed I think explains why the Hayabusa-2 science team decided to delay its own landing for a few months so they could figure out a plan. It really appears that Ryugu does not have any smooth flat spots, as expect.

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Astronomers double the number of known fast radio bursts

9:31 am

Using a radio telescope in Australia astronomers have now doubled the number of known fast radio bursts.

Fast radio bursts come from all over the sky and last for just milliseconds. Scientists don’t know what causes them but it must involve incredible energy—equivalent to the amount released by the Sun in 80 years.

“We’ve found 20 fast radio bursts in a year, almost doubling the number detected worldwide since they were discovered in 2007,” said lead author Dr Ryan Shannon, from Swinburne University of Technology and the OzGrav ARC Centre of Excellence.

In other words, only forty bursts total have ever been detected. The data here however suggests that the bursts are coming from very far away and from the early universe, information which will help scientists figure out what is causing them.

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Hayabusa-2 landing on Ryugu delayed until January

9:22 am

Because of the roughness of the surface of Ryugu, the Hayabusa-2 science team has decided to delay the landing of the spacecraft on the asteroid from the end of this month until late January at the earliest.

JAXA project manager Yuichi Tsuda said they needed more time to prepare the landing as the latest data showed the asteroid surface was more rugged than expected.

“The mission … is to land without hitting rocks,” Tsuda said, adding this was a “most difficult” operation. “We had expected the surface would be smooth … but it seems there’s no flat area.”

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This decision is a wise one. They will have the ability to land very precisely, and this will give them time to find the least risky spot. It does indicate however that the landing itself is going to be risky, which is probably why they want more time to gather data beforehand. Should the landing fail, the mission will essentially be over. This way they can maximize what they learn.

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Ceres’s poles have shifted by as much as 36 degrees

10:31 am

A new analysis of Dawn data suggests that the poles of Ceres have wandered by as much as 36 degrees, and the data also adds further support for the existence of a liquid water layer between the dwarf planet’s crust and mantle.

“The most surprising aspect of this paper is to me the observation that the pole of Ceres must have followed an indirect path to its current pole. A multi-step reorientation could mean that the equatorial density anomaly was still evolving during the reorientation, and this could be because the crust and mantle were weakly rotationally coupled, allowing the crust to start reorienting while the mantle would lag behind,” Tricarico said. “If crust and mantle are allowed to shift with respect to one another, that could point to a layer of reduced friction between crust and mantle, and one of the possible mechanisms to reduce friction could be an ancient water ocean beneath the crust.”

In other words, the crust and mantle are not locked together. Imagine a baseball where the ballcover is not tightly held to the inner core, and slides around it. (Boy there are a lot of pitchers who wish they could get a hand on that baseball.) The cause of that looseness on Ceres is possibly because of a liquid layer in-between the crust and the mantle.

Need I note that there are uncertainties here?

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Sunspot update September 2018: Minimum!

9:58 am

NOAA yesterday released its monthly update of the solar cycle, covering sunspot activity for September 2018. As I have done every month since this website began in July 2011, I am posting it below, annotated to give it some context.

Sunspot activity on the Sun in September dropped slightly from August. More significantly, the activity continues to match closely the weak activity seen in 2008, when the Sun last went through its last solar minimum. We are unquestionably now in the new minimum, and its arrival in the past few months makes the now-ending solar cycle about one to two years shorter than predicted.

September 2018 sunspot activity

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

As I noted last month, the NOAA graph is now getting very close to its right edge, which ends in December 2019. They will very soon have to update this graph so that it can take us into the next solar cycle.

What that new cycle will bring will be the next mystery. I have been following this cycle now since its unusual beginning, with a solar minimum much much longer and more inactive than any solar scientist had ever expected. We can only guess at the surprises the Sun will give us in the coming decade, especially since the science of solar sunspot activity remains superficial and in its infancy. We do not really understand why the Sun’s activity fluctuates. Nor do we understand why it periodically stops producing sunspots for long periods, resulting in what solar scientists call a grand minimum.

There are some scientists who think another grand minimum is coming. We shall have to wait and see. I certainly am going to follow their upcoming observations, as this work remains one of the great scientific studies humans are presently pursuing.

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The central peaks of Copernicus crater

9:41 am

Central peaks of Copernicus Crater

Cool image time! Lunar Reconnaissance Orbiter science team has released a new image of the central peaks of Copernicus Crater, shown on the right cropped and reduced in resolution.

Copernicus (9.62°N, 339.92°E), which is easily seen with a moderately powerful backyard telescope, is one of the best-known craters on the Moon. Despite its age (around 860 million years), it is well preserved with over 4000 meters of relief from floor to rim, and the tallest of its central peaks rises approximately 1300 meters above the crater floor. This image, centered on the central peaks, was captured just after dawn (86° incidence angle) as the Lunar Reconnaissance Orbiter slewed west to a 67°angle.

The image is similar to one taken back in 2012, but has a higher resolution because it was shot from 50 miles elevation instead of 75.

This crater was also the subject of one of the first breath-taking images ever taken of the Moon from lunar orbit, by Lunar Orbiter in November 1966.

The wider view taken by LRO gives some context for the image above. The peaks shown in closeup here are part of the lower right grouping. If you go to the first link above you can zoom in and explore all parts of the full image, and see some quite amazing details, including the large boulders scatter throughout the hollows between the peaks.

Copernicus Crater

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Giant ice pinnacles on Europa

9:15 am

In a new paper scientists note that getting the congressionally mandated Europa Clipper safely to the surface of Jupiter’s moon might be threatened by the existence there of forests of giant five-story high ice pinnacles.

Probes have shown that Europa’s ice-bound surface is riven with fractures and ridges, and new work published today in Nature Geosciences suggests any robotic lander could face a nasty surprise, in the form of vast fields of ice spikes, each standing as tall as a semitruck is long.

Such spikes are created on Earth in the frigid tropical peaks of the Andes Mountains, where they are called “pentinentes,” for their resemblance to devout white-clad monks. First described by Charles Darwin, pentinentes are sculpted by the sun in frozen regions that experience no melt; instead, the fixed patterns of light cause the ice to directly vaporize, amplifying minute surface variations that result in small hills and shadowed hollows. These dark hollows absorb more sunlight than the bright peaks around them, vaporizing down further in a feedback loop.

This work is based on computer models, so it has a lot of uncertainty. It also appears to assume that these pentinentes will be widespread across Europa’s equatorial regions, something so unlikely I find it embarrassing that they even imply it. I guarantee Europa’s surface will be more varied than that. If they are designing Europa Clipper properly, it will go into orbit first to scout out the best landing site, and will be able to avoid such hazards.

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Hubble in safe mode, down to two gyroscopes

8:52 am

The end might be near: The Hubble Space Telescope went into safe mode this weekend when one of its three working gyroscopes failed.

Hubble has six gyroscopes, all of which were replaced by spacewalking astronauts during a servicing mission in May 2009. The telescope needs three working gyroscopes to “ensure optimal efficiency,” mission team members have written, and the failure brings that number down to two (if the “problematic” one that had been off can’t be brought back online).

But that doesn’t mean it’s time to panic. Hubble can do good science with two gyroscopes, or even one, astrophysicist Grant Tremblay, of the Harvard-Smithsonian Center for Astrophysics, said via Twitter Sunday.

While it is true that Hubble can do science on one or two gyroscopes, in that mode it will no longer be able to take the sharp spectacular pictures that represent its great glory.

Hubble was launched in 1990, fixed in 1993, and has been the most successful science robot ever launched. Scientists had hoped, when they made the James Webb Space Telescope their priority in the very early 2000s that both would be in space and operating to provide top notch science data, with Hubble working in visible wavelengths and Webb in the infrared. Webb’s endless delays and cost overruns has now probably made that impossible.

Worse, there are no plans to build a replacement for Hubble. For the first time since 1993, the human race will no longer be able to see, with our own eyes, the universe sharply.

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Data from Voyager 2 suggests it is entering interstellar space

7:50 pm

New data since August from Voyager 2 now suggests it is finally leaving the heliosphere of the solar system and entering interstellar space.

Since late August, the Cosmic Ray Subsystem instrument on Voyager 2 has measured about a 5 percent increase in the rate of cosmic rays hitting the spacecraft compared to early August. The probe’s Low-Energy Charged Particle instrument has detected a similar increase in higher-energy cosmic rays.

Cosmic rays are fast-moving particles that originate outside the solar system. Some of these cosmic rays are blocked by the heliosphere, so mission planners expect that Voyager 2 will measure an increase in the rate of cosmic rays as it approaches and crosses the boundary of the heliosphere.

In May 2012, Voyager 1 experienced an increase in the rate of cosmic rays similar to what Voyager 2 is now detecting. That was about three months before Voyager 1 crossed the heliopause and entered interstellar space.

The scientists warn that there is great uncertainty here, and that the actual transition into interstellar space might take longer than with Voyager 1 since Voyager 2 is traveling in a different direction and is leaving during a different time in the solar cycle.

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Images of Mascot by Hayabusa released

7:43 pm

MASCOT descending towards Ryugu

The Hayabusa-2 science team today released images taken of MASCOT as it descended to the surface of Ryugu, including images showing where it landed.

In the image on the right, reduced slightly to post here, you can see MASCOT as it slowly moves downward towards the asteroid shortly after its release from Hayabusa-2. At the link there is another image showing the mini-lander as a white dot when it was still about 115 feet above the surface. Other images show its location on the surface where it operated for seventeen hours and completed three hops.

The next big event from Hayabusa-2 will be the spacecraft’s own landing, sometime later this month.

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New Horizons makes final big course correction

7:26 pm

New Horizons this week successfully made its final major course correction in preparation for its January 1st fly-by of the Kuiper Belt object the science team has dubbed Ultima Thule.

NASA’s New Horizons spacecraft carried out a short engine burn on Oct. 3 to home in on the location and timing of its New Year’s flyby of the Kuiper Belt object nicknamed Ultima Thule.

Word from the spacecraft that it had successfully performed the 3½-minute maneuver reached mission operations at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, at around 10:20 p.m. EDT. The maneuver slightly tweaked the spacecraft’s trajectory and bumped its speed by 2.1 meters per second – just about 4.6 miles per hour – keeping it on track to fly past Ultima (officially named 2014 MU69) at 12:33 am EST on Jan. 1, 2019.

As the spacecraft gets closer they will do more refinements, but right now they are a very precise course. The January 1st fly-by will end a spectacular fall season of planetary mission rendezvous, landings, fly-bys and sample gatherings.

Posted from Chicago.

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MASCOT ends its mission on Ryugu, as planned

10:52 pm

Hayabusa-2’s mini-lander MASCOT has ended its mission on Ryugu after seventeen hours, slightly longer than the planned sixteen hours.

The lander made one hop, and successfully transmitted all its data back to Hayabusa-2, which still has one more mini-lander on board that will be sent to Ryugu’s surface, probably after Hayabusa-2 makes its own landing.

Meanwhile, the two Minerva-2 bouncers continue to operate on Ryugu.

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A vent on Mars?

1:29 pm

A vent on Mars?

Cool image time! In their exploration of the surface of Mars using Mars Reconnaissance Orbiter (MRO), scientists often image geological features that strongly resemble Earth features. Sometimes, if real, the resemblances are significant, as they indicate important geological activity on Mars that can tell us a lot about the conditions and environment there.

The image on the right, cropped and reduced in resolution to post here, is a good example of this. It was taken by MRO on June 14, 2018, just before the global dust storm obscured the planet’s middle latitudes for most of the summer, and was part of the monthly release of new images from the spacecraft. (If you click on the image you can see the full resolution picture.) The release website, which includes no caption, describes this feature as an “apparent vent,” a determination that certainly seems reasonable. The shadowed dark features suggest an abrupt oblong pit near the edge of a cliff, formed in the center of a collapsed sink. The tear-drop shape of the collapse sink and surrounding darkened areas also suggests that something is venting from it and then blowing away to the east and south, forming the darker stained ground. Some of the dark features to the southeast might also be smaller vents, releasing their own materials into the atmosphere.

The location also reinforces this suggestion, located on the southeast lava slopes of one of Mars’ larger volcanoes, Elysium Mons. This is also a region, dubbed Athabasca Valles, that some planetary scientists believe is one of the youngest lava flows on Mars.

Finally, it appears that the pit here has darkened considerably recently. MRO has taken images of this pit twice previously, in 2008 and 2010, and in both images the pit is much lighter in color, with its sandy dune-covered floor much easier to see. In the new image the floor is now very dark. This might be caused by shadows and the angle of the Sun, but I don’t believe so. It is also clear when comparing all three images that the surrounding area, including the flow to the southeast, has also darkened with time.

All this data suggests that the pit is venting something into the air, and it is settling on the ground to the southeast, blown there by the prevailing winds. Nor is this pit the only such feature in this region. Other images by MRO show a lot of similar dark splotches.

The problem is that this feature is not on Earth but on Mars. Determining what is being vented, and why, is therefore made more difficult. Based on Earth data you would assume this is some form of volcanic vent, releasing gases from below the surface. On Mars that assumption might not hold. We might instead be seeing the venting of any number of possible materials, such as underground water-ice, carrying with it other underground materials and thus darkening the surface.

We also can’t assume that the venting is occurring because of volcanic processes. On Mars the evidence so far gathered suggests that active volcanic activity ceased a very long time ago, even for this very young lava region. The venting is likely caused by something else, a fact that in itself is probably the most significant take-away from these images.

Something appears to be causing an active vent on the surface of Mars. Finding out the root cause of that venting is probably one of the more interesting questions facing researchers who study the Martian surface.

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NASA study says deep space will cause cancer and destroy stomachs

8:35 am

We’re all gonna die! A NASA study on rats using simulated space radiation suggests that long duration space missions beyond Earth orbit will cause cancer as well as significant harm to human intestines.

The study, published by cancer researchers at Georgetown University Medical Center, used mice to test exposure to heavy ion radiation, which mimics the galactic cosmic radiation found in deep space. If that sounds complicated, essentially researchers compared “space” radiation to X-ray radiation and found its effects to be much more dangerous.

After long exposures to a low dose of galactic radiation, mice had permanent damage to their gastrointestinal tracts and could no longer absorb nutrients in food. The mice also developed cancerous growths in their intestines — raising concerns that astronauts who venture far into space would face the same deadly health issues. “While short trips, like the times astronauts traveled to the moon, may not expose them to this level of damage, the real concern is lasting injury from a long trip,” said Kamal Datta, head of Georgetown’s NASA Specialized Center of Research, in a press release.

More here.

Must I point out the uncertainties and weaknesses of this study? They did the test on rats. They simulated the radiation. And it appears they simulated the radiation dosages assuming the spacecraft would have little or no shielding, an absurd approach.

Space is dangerous, but there is no reason to exaggerate the dangers wildly, unless you wish to generate fake reasons for additional funding, as NASA is prone to do.

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Curiosity to switch computers in effort to restore operations

10:44 pm

The Curiosity engineering team have decided to switch on-board computers in effort to figure out why the rover has been unable to store and send any data since September 15.

After reviewing several options, JPL engineers recommended that the rover switch from Side B to Side A, the computer the rover used initially after landing.

The rover continues to send limited engineering data stored in short-term memory when it connects to a relay orbiter. It is otherwise healthy and receiving commands. But whatever is preventing Curiosity from storing science data in long-term memory is also preventing the storage of the rover’s event records, a journal of all its actions that engineers need in order to make a diagnosis. The computer swap will allow data and event records to be stored on the Side-A computer.

Side A experienced hardware and software issues over five years ago on sol 200 of the mission, leaving the rover uncommandable and running down its battery. At that time, the team successfully switched to Side B. Engineers have since diagnosed and quarantined the part of Side A’s memory that was affected so that computer is again available to support the mission. [emphasis mine]

As indicated by the highlighted paragraph, the switch does carry some risk. Though they say they have isolated the problems with the A computer, they might be surprised when they turn it on.

Meanwhile, silence continues from Opportunity. After fourteen years of almost continuous rover operations on Mars, the United States have been roverless now for more than two weeks.

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The first exomoon found?

11:29 am

Worlds without end: Scientists using data from the Hubble Space Telescope and Kepler have detected evidence that suggests the discovery of the first moon outside our solar system.

The data indicate an exomoon the size of Neptune, in a stellar system 8000 light-years from Earth. The new results are presented in the journal Science Advances.

…In 2017 NASA’s Kepler Space Telescope detected hints of an exomoon orbiting the planet Kepler-1625b. Now, two scientists from Columbia University in New York (USA) have used the incomparable capabilities of the NASA/ESA Hubble Space Telescope to study the star Kepler-1625, 8000 light-years away, and its planet in more detail. The new observations made with Hubble show compelling evidence for a large exomoon orbiting the only known planet of Kepler-1625. If confirmed, this would be the first discovery of a moon outside our Solar System.

The candidate moon, with the designation Kepler-1625b-i, is unusual because of its large size; it is comparable in diameter to the planet Neptune. Such gargantuan moons are unknown in our own Solar System. “This may yield new insights into the development of planetary systems and may cause astronomers to revisit theories of how moons form,” Alex Teachey, a graduate student who led the study, explained excitedly.

Like its moon, Kepler-1625b is also bigger than its counterparts in the Solar System. The exoplanet is a gas giant, several times more massive than Jupiter. It orbits its parent star at a distance similar to the distance between the Sun and Earth, which puts it — and its candidate moon — at the inner edge of the habitable zone of the star system.

The alien nature of this solar system should not surprise us. If anything, it is only a hint at the wild and exotic solar systems we have yet to discover.

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Astronomers discover very distant object orbiting the Sun

9:32 am

Astronomers have discovered a very distant object in a solar orbit ranging from 6 billion to 213 billion miles from the Sun.

Designated 2015 TG387 and nicknamed “The Goblin” by its discoverers, this object resides in the inner Oort Cloud, a region beyond the Kuiper Belt that until now harbored only two other known bodies: the dwarf planet Sedna and the less well-known 2012 VP113.

The scientists estimate its size to be about 200 miles in diameter. Based on the existence of the three known objects in this region of space, the scientists estimate there could be as many as 2 million objects there bigger than 25 miles in diameter. There is a lot of uncertainty in that number.

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Hayabusa-2’s third mini-lander successfully lands on Ryugu

8:55 am

MASCOT image of Ryugu surface

Update: The image at right, reduced to post here, was taken by MASCOT during its descent. You can see the spacecraft’s shadow in the upper right. If you click on the image you can see the full resolution version.

Original post: The German/French-build mini-lander MASCOT has been successfully deployed by Hayabusa-2 and has successfully landed on the asteroid Ryugu.

MASCOT came to rest on the surface approximately 20 minutes after the separation. Now, the team is analysing the data that MASCOT is sending to Earth to understand the events occurring on the asteroid Ryugu. The lander should now be on the asteroid’s surface, in the correct position thanks to its swing arm, and have started to conduct measurements independently. There are four instruments on board: a DLR camera and radiometer, an infrared spectrometer from the Institut d’Astrophysique Spatiale and a magnetometer from the TU Braunschweig. Once MASCOT has performed all planned measurements, it is expected to hop to another measuring location. This is the first time that scientists will receive data from different locations on an asteroid.

The spacecraft took 20 pictures during its descent, which were beamed to Hayabusa-2 where they are presently stored.

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More intergalactic stars discovered

9:22 am

Worlds without end: Using the data from Gaia’s second data release astronomers have identified twenty stars that are moving too fast to be permanent members of the Milky Way galaxy.

More significantly, most appeared to be approaching the galaxy, not flying away from it, suggesting they are visitors from other galaxies.

It is possible that these intergalactic interlopers come from the Large Magellanic Cloud, a relatively small galaxy orbiting the Milky Way, or they may originate from a galaxy even further afield. If that is the case, they carry the imprint of their site of origin, and studying them at much closer distances than their parent galaxy could provide unprecedented information on the nature of stars in another galaxy – similar in a way to studying Martian material brought to our planet by meteorites.

…An alternative explanation is that the newly identified sprinting stars could be native to our Galaxy’s halo, accelerated and pushed inwards through interactions with one of the dwarf galaxies that fell towards the Milky Way during its build-up history. Additional information about the age and composition of the stars could help the astronomers clarify their origin.

At least two more data releases shall come from Gaia, launched by Europe to precisely track the location and motions of a billion stars. So far, they have complete 3D velocity information for about seven million stars. After these additional data releases they expect to have complete 3D velocity information for 150 million stars, and should identify a lot more intergalactic stars at that time.

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Deployment operations for Hayabusa-2’s MASCOT lander have begun

9:07 am

Engineers have begun the deployment sequence for Hayabusa-2’s MASCOT lander, with deployment planned for tomorrow.

Right now Hayabusa-2 is slowly moving closer to Ryugu, with live images appearing about once every half hour. More information about MASCOT can be found here. The lander can also hop like the MINERVA bouncers, but it can only do it once. Its battery life is about sixteen hours, so once it is deployed it will only operate on the surface for a short while.

Both the MINERVA and MASCOT mini-landers are mostly engineering tests for using small cubesat-sized spacecraft as probes. So far the MINERVA bouncers have been an unqualified success. Hopefully MASCOT will be as successfully.

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Breakthrough Listen adds southern hemisphere telescope to extraterrestrial listening campaign

8:51 am

Breakthrough Listen has added the MeerKAT telescope in South Africa to its extraterrestrial listening campaign, thereby expanding the campaign to cover almost the entire sky.

Breakthrough Listen’s MeerKAT survey will examine a million individual stars – 1,000 times the number of targets in any previous search – in the quietest part of the radio spectrum, monitoring for signs of extraterrestrial technology. With the addition of MeerKAT’s observations to its existing surveys, Listen will operate 24 hours a day, seven days a week, in parallel with other surveys. “Collaborating with MeerKAT will significantly enhance the capabilities of Breakthrough Listen”, said Yuri Milner, founder of the Breakthrough Initiatives. “This is now a truly global project.”

Built and operated by the South African Radio Astronomy Observatory (SARAO), and inaugurated in July 2018, MeerKAT is a powerful array of 64 radio antennas in the remote Karoo Desert of South Africa. By partnering with SARAO, Breakthrough Listen gains access to one of the world’s premier observing facilities at radio wavelengths. Signals from the 64 dishes (each 13.5 meters in diameter) are combined electronically to yield an impressive combination of sensitivity, resolution and field of view on the sky. MeerKAT also serves as a precursor for the Square Kilometre Array, which will expand and enhance the current facility in the coming decades, eventually spanning a million square meters across South Africa and Australia to create by far the world’s largest radio telescope.

They have also widened their approach. They are not simply looking for intelligent radio communications, they are looking for any signs of technology.

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NASA extends Chandra telescope operation to 2024

8:02 am

NASA has extended its contract with the Smithsonian Astrophysical Observatory in Massachusetts to run the Chandra X-ray Observatory through 2024.

In many ways the longevity of both Hubble and Chandra as well as other space telescopes has demonstrated the robustness of much in-space engineering these days. It suggests that when we finally begin building manned interplanetary spaceships we should have confidence they will operate reliably for long periods.

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Four candidate stars identified as home for Oumuamua

8:14 am

The uncertainty of science: Astronomers have identified four stars as possible home stars for the interstellar object Oumuamua.

Bailer-Jones and his colleagues found four stars that are possible candidates for ‘Oumuamua’s home world. All four of them are dwarf stars. The one that came closest to ‘Oumuamua, at least about one million year ago, is the reddish dwarf star HIP 3757. It approached within about 1.96 light-years. Given the uncertainties unaccounted for in this reconstruction, that is close enough for ‘Oumuamua to have originated from its planetary system (if the star has one). However, the comparatively large relative speed (around 25 km/s) makes it less probable for this to be ‘Oumuamua’s home.

The next candidate, HD 292249, is similar to our Sun, was a little bit less close to the object’s trajectory 3.8 million years ago, but with a smaller relative speed of 10 km/s. The two additional candidates met ‘Oumuamua 1.1 and 6.3 million years ago, respectively, at intermediate speeds and distances. These stars have been previously catalogued by other surveys, but little is known about them.

There is much uncertainty here. None of these stars might be Oumuamua’s actual original star, but might have instead shifted its orbit from its past course.

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Dust storms spotted on Titan

7:44 pm

Scientists reviewing Cassini data have identified dust storms for the first time of Saturn’s moon Titan.

When Rodriguez and his team first spotted three unusual equatorial brightenings in infrared images taken by Cassini around the moon’s 2009 northern equinox, they thought they might be the same kind of methane clouds; however, an investigation revealed they were something completely different. “From what we know about cloud formation on Titan, we can say that such methane clouds in this area and in this time of the year are not physically possible,” said Rodriguez. “The convective methane clouds that can develop in this area and during this period of time would contain huge droplets and must be at a very high altitude — much higher than the 6 miles (10 kilometers) that modeling tells us the new features are located.”

The researchers were also able to rule out that the features were actually on the surface of Titan in the form of frozen methane rain or icy lavas. Such surface spots would have a different chemical signature and would remain visible for much longer than the bright features in this study, which were visible for only 11 hours to five weeks.

In addition, modeling showed that the features must be atmospheric but still close to the surface — most likely forming a very thin layer of tiny solid organic particles. Since they were located right over the dune fields around Titan’s equator, the only remaining explanation was that the spots were actually clouds of dust raised from the dunes.

Obviously there are large uncertainties here. Nonetheless, the conclusion is a reasonable one, as it is expected that such dust storms would occur on Titan.

Posted just outside Zion National Park in the town of Springdale.

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