Tag: science

Astronomers identify 25 stars that have or will come within 3 light years of Sun

9:21 am

Using the second data release from Gaia, astronomers have identified 25 stars that have or will come within 3 light years of Sun sometime within fifteen million years.

But the authors are confident that the 25 stars represent only a sliver of the actual encounters that have occurred over this time period. “They’re still just scratching the surface,” Mamajek agrees. That’s because the Gaia satellite eliminates low-mass stars (which are simply too faint to see at the moment) and high-mass stars (which are often so bright they saturate the satellite’s detectors) — thus limiting the data to stars that range between 0.5 and 1.3 times the mass of the Sun.

As such, the team suspects that they have only spotted 15% of all the encounters that likely pummel our solar system. “It’s a good first step, but one should not look at this as the final word,” Mamajek adds.

In reading their paper (available here), they identify three stars come come within a light year, therefore disturbing the theorized Oort Cloud of comets thought to exist at this distance from the Sun. One, Gliese 710, will do so in 1.3 million years..

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Update on Hawaiian lava eruption

10:15 am

Link here. This news article is particularly informative, as it includes a map that outlines the extent of the lava flows and what they have engulfed, including the most recent flows that are threatening a geothermal power plant that has been providing the Big Island about 25% of its power.

“Lava flow from Fissures 7 and 21 crossed into PGV [Puna Geothermal Venture] property overnight and has now covered one well that was successfully plugged,” declared the Hawaii Civil Defense Agency in a statement released on Sunday, May 27 at 6:00 pm local time. “That well, along with a second well 100 feet [30 meters] away, are stable and secured, and are being monitored. Also due to preventative measures, neither well is expected to release any hydrogen sulfide.”

Those preventive measures included a complete shutdown of the geothermal plant, the capping of all 11 wells, and the removal of some 60,000 gallons of flammable liquid. Those precautions aside, this is the first time in history—as far as we know—that lava has ever engulfed a geothermal power plant, so it’s all uncharted territory. There’s fear that a rupture of the wells could set off an explosion, releasing hydrogen sulfide and other dangerous gasses into the environment. As of this posting, the lava flows on the PGV grounds have stopped moving.

Environmentalists often promote geothermal power as an alternative to fossil fuels. Environmentalists also sued to prevent this plant from being built because of its proximity to the volcano.

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China loses contact with one of two lunar cubesats

8:59 am

China has lost contact with one of the two test cubesats that were launched to the moon with their Queqiao Chang’e-4 communications satellite.

Though they continue to receive telemetry from one cubesat, without the second they will be unable to do the radio astronomy and interferometry experiments planned.

The interferometry experiments would have seen the observations made simultaneously by the DSLWP/Longjiang microsatellites to be combined. The test would be verification of technology for a constellation of small, low-frequency radio astronomy satellites that would emulate a telescope with a size equal to the maximum separation between the satellites.

The Chang’e-4 mission could however see some interferometry tests carried out, with Queqiao carrying the Netherlands-China Low-frequency Explorer (NCLE) astronomy instrument, and a Low Frequency Spectrometer (LFS) on the Chang’e-4 lander, which is expected to launch in November or December, following testing of Queqiao.

All is not lost. The cubesat that still functions has a camera, built in Saudi Arabia, and if it takes and successfully transmits any pictures this will be a cubesat landmark, the first interplanetary images ever taken by a cubesat.

Meanwhile, Queqiao Change’-4 is working as expected, laying the ground work for the launch of the Chang’e-4 lander later this year.

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New NOAA weather satellite has serious problem

9:27 pm

Can’t anybody here play this game? The cooling unit required to take infrared images in the new NOAA weather satellite GOES-17, launched in March, is not functioning properly.

“This is a serious problem,” Volz said Wednesday in a conference call with reporters. “This is the premier Earth-pointing instrument on the GOES platform, and 16 channels, of which 13 are infrared or near-infrared, are important elements of our observing requirements, and if they are not functioning fully, it is a loss. It is a performance issue we have to address.”

Detectors for the infrared channels must be cooled to around 60 Kelvin (minus 351 degrees Fahrenheit) to make them fully sensitive to infrared light coming from Earth’s atmosphere. For about 12 hours each day, the cooler inside the Advanced Baseline Imager, or ABI, is unable to chill the detectors to such cold temperatures, officials said.

Infrared images from weather satellites are used to monitor storms at night, when darkness renders visible imagery unavailable. The three visible channels from the ABI are not affected by the cooling problem.

“The other wavelengths, the near-infrared and infrared wavelengths — the other 13 — need to be cooled to some extent beyond the capability of the system at present,” said Tim Walsh, NOAA’s program manager for the GOES-R weather satellite series. “There’s a portion of the day centered around satellite local midnight where the data is not usable, and that’s what we’re addressing.”

GOES-17 is the second of a four satellite constellation being built by NOAA costing $11 billion.

It appears that an identical cooling system was installed on the first of this satellite constellation, GOES-16, and has been working perfectly in orbit since November 2016. Why the new unit isn’t working remains a puzzle.

The real issue here is the cost and complexity of these satellites. Because they are so complex and take so long to build, replacing them is difficult if not impossible. Wouldn’t it be better to launch many cheaper satellites to provide redundancy at a lower cost?

This is a pattern we see throughout the government aerospace industry. NASA’s Webb and WFIRST telescopes are big and take decades to build. God forbid they fail at launch. SLS and Orion are big and take decades to build. God forbid they fail at launch. The Air Force’s numerous military satellites are big and take decades to build. God forbid an enemy takes one out.

In all these cases, failure means we get nothing after spending a lot of time and money. And replacing the loss will take years and billions of dollars.

Common sense says it is time to rethink this entire operation. Unfortunately, this is the federal government. The concept of rethinking anything, or even thinking at all, is too often a completely alien concept. I do not expect anything to change, unless we elect new people in Congress and the Presidency who are willing to take a hammer to this whole insane system and smash it bluntly. Trump is kind of this type of new person, but even he isn’t willing to change that much, only some things, such as the EPA, that irk him in particular. Otherwise, he has left much of the federal bureaucracy alone — as can be seen by his administration and NASA both gearing up to fund both LOP-G and WFIRST— thus continuing this pattern of big and expensive projects that take forever to build.

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Mars rover update: May 23, 2018

3:35 pm

Summary: Curiosity drives down off of Vera Rubin Ridge to do drilling in lower Murray Formation geology unit, while Opportunity continues to puzzle over the formation process that created Perseverance Valley in the rim of Endeavour Crater.

For a list of past updates beginning in July 2016, see my February 8, 2018 update.

Curiosity

Curiosity's travels on and off Vera Rubin Ridge

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

Since my April 27, 2018 update, Curiosity has continued its downward trek off of Vera Rubin Ridge back in the direction from which it came. The annotated traverse map to the right, cropped and taken from the rover’s most recent full traverse map, shows the rover’s recent circuitous route with the yellow dotted line. The red dotted line shows the originally planned route off of Vera Rubin Ridge, which they have presently bypassed.

It appears they have had several reasons for returning to the Murray Formation below the Hematite Unit on Vera Rubin Ridge. First, it appears they wanted to get more data about the geological layers just below the Hematite Unit, including the layer immediately below, dubbed the Blunts Point member.

While this is certainly their main goal, I also suspect that they wanted to find a good and relatively easy drilling candidate to test their new drill technique. The last two times they tested this new technique, which bypasses the drill’s stuck feed mechanism by having the robot arm itself push the drill bit against the rock, the drilling did not succeed. It appeared the force applied by the robot arm to push the drill into the rock was not sufficient. The rock was too hard.

In these first attempts, however, they only used the drill’s rotation to drill, thus reducing the stress on the robot arm. The rotation however was insufficient. Thus, they decided with the next drill attempt to add the drill’s “percussion” capability, where it would not only rotate but also repeatedly pound up and down, the way a standard hammer drill works on Earth.

I suspect that they are proceeding carefully with this because this new technique places stress the operation of the robot arm, something they absolutely do not want to lose. By leaving Vera Rubin Ridge they return to the more delicate and softer materials already explored in the Murray Formation. This is very clear in the photo below, cropped from the original to post here, showing the boulder they have chosen to drill into, dubbed “Duluth,” with the successful drill hole to the right.
» Read more

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Drilling success for Curiosity

11:16 am

For the first time in more than a year, Curiosity has successfully used its drill to obtain a sample from beneath the surface of Mars.

Curiosity tested percussive drilling this past weekend, penetrating about 2 inches (50 millimeters) into a target called “Duluth.”

NASA’s Jet Propulsion Laboratory in Pasadena, California, has been testing this drilling technique since a mechanical problem took Curiosity’s drill offline in December of 2016. This technique, called Feed Extended Drilling, keeps the drill’s bit extended out past two stabilizer posts that were originally used to steady the drill against Martian rocks. It lets Curiosity drill using the force of its robotic arm, a little more like the way a human would drill into a wall at home.

I plan to post a rover update either today or tomorrow, with more details about this success. Stay tuned!

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Pluto formed from a billion comets?

9:09 am

Scientists have come up with a new theory for the origin of Pluto, based on data from New Horizons and Rosetta, that suggests the planets formed from the accretion of a billion comets or Kuiper Belt objects.

“We’ve developed what we call ‘the giant comet’ cosmochemical model of Pluto formation,” said Dr. Christopher Glein of SwRI’s Space Science and Engineering Division. The research is described in a paper published online today in Icarus. At the heart of the research is the nitrogen-rich ice in Sputnik Planitia, a large glacier that forms the left lobe of the bright Tombaugh Regio feature on Pluto’s surface. “We found an intriguing consistency between the estimated amount of nitrogen inside the glacier and the amount that would be expected if Pluto was formed by the agglomeration of roughly a billion comets or other Kuiper Belt objects similar in chemical composition to 67P, the comet explored by Rosetta.”

This is only a hypothesis, but it is intriguing. It suggests that Pluto’s make-up came only from the outer parts of the solar system, thus constraining how much mixing between the solar system’s inner and outer regions occurred. For scientists trying to understand the formation of the entire solar system, this lack of mixing would be significant. It means that the gas giants, while migrating inward, never migrated outward.

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Why jets formed on Comet 67P/C-G

9:02 am

Scientists analyzing the data produced by Rosetta while it was flying in formation with Comet 67P/C-G have determined that the comet’s complex topology acted almost like nozzles to encourage evaporating material to form jets.

The new study shows for the first time that mainly the unusual shape and jagged topography of the comet are responsible for this phenomenon. The researchers analyzed images at different observation geometries of the Hapi region located on the “neck” of the comet, the narrow part connecting its two lobes. In computer simulations, they were able to reproduce these images thus gaining a better understanding of the driving processes.

In particular, two effects proved to be decisive. Some regions on the surface are located at lower altitudes or in the shade. The first rays of sunlight reach them later. In contrast, the frost evaporates particularly efficiently from the early and strongly illuminated regions. In addition, pits and other concave structures virtually concentrate gas and dust emissions – much like an optical lens.

This means that predicting the evaporation patterns on other comets will require first obtaining a detailed map of the surface, showing both its topography and make-up. This also means that any future explorers will first have to send a robot scouting mission so that they can plan a safe arrival during active periods.

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New tests prove EM drive doesn’t work

11:26 am

Two different alternative concepts that proposed methods for creating thrust in space but defied known physics have both been found wanting in new stringent experiments.

The EM drive especially came off badly. Apparently the tiny residual force that remains after building the experiment rigorously and with care is caused not by the EM drive but by the Earth’s magnetic field.

Readers of Behind the Black know that I am a strong skeptic when it comes to flashy new discoveries, whether they are made by famous and well known cosmologists or some guys in their garage. To me, what matters is the data, and its reliability and robustness. The EM drive never passed the smell test. Good science experimentation has now proven this.

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Two giant U.S. telescope projects team up

9:21 am

The two consortiums building the Thirty Meter Telescope (TMT) and the Giant Magellan Telescope (GMT) have teamed up in order to coordinate their research as well as encourage increased government funding for both.

The partnership, approved by the GMT board this month and by the TMT board last month, commits the two projects to developing a joint plan that would allow astronomers from any institution to use the telescopes; under previous plans observing time was available only to researchers from nations or institutions that had provided funding. The projects are discussing awarding at least 25% of each telescope’s time to nonpartners through a competitive process to be administered by the National Center for Optical-Infrared Astronomy—an umbrella organization that will replace the National Optical Astronomy Observatory (NOAO), based in Tucson, Arizona, sometime in fiscal year 2019. Telescope backers hope the public access plan will help persuade the federal government to pay for at least 25% of the total cost of the two facilities, which could total $1 billion. (Cost estimates for the GMT and the TMT are $1 billion and $1.4 billion, respectively, but astronomers expect both numbers to grow.) “There are many science projects that are $1 billion class projects,” says David Silva, NOAO’s director. “The investment that we would want is of a similar size.”

…In making their case, the teams will argue the benefits of having telescopes in both the northern and southern hemispheres. “When you are covering the whole sky, you have greater scientific reach,” says Wendy Freedman, an astronomer at The University of Chicago in Illinois who was the founding leader of the GMT. The teams will also argue that the telescopes have complementary strengths. The design of the GMT, for instance, makes it ideal for a high-resolution spectrograph designed to probe the atmospheres of exoplanets. The TMT, which has more light-gathering power, could host a multiobject spectrograph to quickly gather demographic statistics on the universe’s first galaxies. [emphasis mine]

The highlighted sentences explain everything. First, government funding for both projects has been weak, partly because the National Science Foundation (the funding agency) has not been able to make up it mind which of these two U.S. projects to back. By teaming up as one project building two telescopes, the builders hope they will grease the wheels of the federal funding machine.

Second, by selling these two telescopes as covering both the north and south hemispheres, they indicate that the TMT is now almost certainly going to abandon its Hawaii location and move to the Canary Islands. GMT will be built at the Las Campanas Observatory in Chile, located at 29 degrees south latitude. By placing TMT in the northern hemisphere at 29 degrees north latitude in the Canary Islands, rather than Mauna Kea’s 19 degrees north latitude, they better compliment GMT in the southern hemisphere.

In other words, this partnership strengthens the case for TMT to abandon Hawaii. Not only will construction begin sooner (as the Hawaiian government has shown no interest in approving the project), the higher latitude as part of this partnership better justifies funding.

And the odds of getting that funding have apparently increased, as the chair of the House appropriations panel that funds the National Science Foundation has just shown himself to be very willing to give telescope projects a lot of money, more in fact than they even request.

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China launches communications relay satellite for upcoming lunar mission

8:41 am

China successfully launched a satellite in the early hours this morning designed to relay communications between the Earth and an upcoming lunar lander aimed for the Moon’s far side.

The landing site for this mission is expected to be the Von Kármán crater in the South Pole-Aitken Basin. If successful, this will be the first spacecraft to land on the far side of the Moon.

As such, a communication relay will be required to communicate with Earth. Queqiao [the communication satellite’s name] will provide that role. Launched to an eventual L2 Halo Orbit (Earth-Moon L2 Lagrange Point), the satellite will have a lifetime of five years, covering both this and potentially another Chang’e mission.

The spacecraft is based on the CAST100 small satellite platform, with commonality to the often used DFHSat system that finds its way on to a number of Chinese spacecraft. It has a mass of 425kg and uses a hydrazine propulsion system. It will transmit telemetry back to Earth via its S-band antenna, while X-band data will provide the communication path between the lander and rover.

This Chinese lander could also be the first to confirm the existence of water ice on the lunar surface.

With this launch China once again ties the U.S. in launches for 2018. The leaders:

15 China
9 SpaceX
5 Russia
5 ULA

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The federal government’s blank check

9:38 am

Three articles this morning about actions taken by Congress in connection with the budgets for NASA and NOAA illustrate the bankrupt nature of our federal government.

The first story describes how several legislators from the House Appropriations Committee have inserted amendments into their budget bill that will restore a $10 million NASA climate monitoring program that the Trump administration had shut down.

The second story describes how that same budget bill generously funds both NASA and NOAA at levels far above their own requests.
» Read more

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Europa water plume detected in old Galileo data

8:22 am

Using old Galileo data and new techniques of analysis scientists have uncovered a water plume on Europa that the spacecraft flew through in 1997.

Over the course of 5 minutes, spikes the spacecraft recorded with its magnetic and plasma sensors reflected the alterations that a veil of ejected water, from one or many vents, could cause in a region matching the telescope observations, they report today in Nature Astronomy. This indicates that a region of the moon potentially 1000 kilometers long could host such activity, though it is impossible to say whether this is a single plume or many, like the complex system of fractures and vents seen on Enceladus. Indeed, on its own, this evidence was too weak to tie to erupting water in a 2001 study describing it, the authors add, but it fits well with the Hubble and modeled evidence.

As indicated by the quote above, the result has a lot of uncertainty.

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Chaos on Mars

11:56 am

chaos terrain

Cool image time! The image on the right, cropped and reduced in resolution to post here, shows an area on Mars that geologists have dubbed “Chaos Terrain.” If you click on the image you can see the full image, which also includes several canyons oriented in what seem to be random directions.

I first heard this geological term for regions on Mars shortly after the first orbital missions circling Mars began taking images back in the 1970s. It applied to places where the terrain was hummocky, a crazy collection of hills forming no pattern at all. Earth does not really have such terrain.

The close-up to the right also shows that at least one of these hills is fractured, made up of several large pieces that have separated over time.

This image was part of the May 2nd image release from the high resolution camera on Mars Reconnaissance Orbiter. What makes it interesting is its location on Mars. The image below shows that location, indicated by a white cross.
» Read more

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Most scientific studies cannot be reproduced

12:13 pm

A new report looking at a number of important research studies has found that almost all could not be reproduced, and that the research was often fraught with fraud and “political groupthink.”

For this study, researchers tried to reproduce the results of “53 landmark studies in oncology and hematology.” Researchers were only able to replicate the results of six studies. “People have found similar results in psychology and economics. Different fields are affected different amounts,” Randall told The College Fix. “As a rule of thumb, fields that use statistics intensively are more likely to have troubles than fields that don’t.”

The report hypothesized that there are a number of different reasons for irreproducibility that include such things as “flawed statistics, faulty data, deliberate exclusion of data, and political groupthink,” among other reasons. “Actual fraud on the part of researchers appears to be a growing problem,” the report also states.

The report also singled out the field of climate science as having significant problems along these same lines, especially in areas of its statistical research.

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Mars Odyssey looks down at Curiosity

10:39 am

Gale Crater

The Mars Odyssey team today released an image the spacecraft took of Gale Crater on January 16, 2018. This image, reduced in resolution, is posted on the right and captures the entire region that the rover Curiosity has been traversing for the past six years. If you click on the image you can view the full resolution original.

I have placed Curiosity’s full route since its landing on this image so that we can see where the rover has been. The actual peak of Mount Sharp is a considerable distance to the south and is not visible in this image. (For the full context of the crater and Curiosity’s travels see my March 2016 post, Pinpointing Curiosity’s location in Gale Crater)

The river-like flow feature cutting through the north rim is called Peace Vallis. Scientists think this was formed by water flowing into the crater when the climate of Mars was wetter and there was a lake inside the crater floor.

You can get another perspective of this same view by looking at the panorama looking north that Curiosity took once it climbed up onto Vera Rubin Ridge.

I have said this before, but this Mars Odyssey image once again illustrates how little of Mars we have so far seen. Curiosity has barely begun its climb into the foothills of Mount Sharp. The mile-high mountains that form the rim of Gale Crater are far away, and will not be walked for probably generations. I do not expect any space probe or explorer to enter Peace Vallis for at least a hundred years, since there are so many other places on Mars to visit and Gale Crater has already gotten its first reconnaissance by Curiosity.

The image also gives as a view of Curiosity’s future travels. Based on this October 3, 2016 press release, Curiosity will eventually head into the mouth of the large canyon directly to the south of its present position. Whether the mission will continue up this canyon wash, using it as the route up Mount Sharp, will depend on many things, including the roughness of the terrain in that canyon and the simple question of whether the rover will be able to operate that long.

If it does, the views then from inside that canyon should be quite breathtaking.

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Juno images processed by citizens highlighted at conference

9:50 am

Several Juno images that have been cleverly processed by citizen scientists are being highlighted at a Jupiter conference being held in London this week.

JunoCam images presented at the meeting by citizen scientists Gerald Eichstädt and Seán Doran include an animation showing the evolution of swirling features in the giant planet’s atmosphere and a composite image of Jupiter’s cloud tops.

Gerald Eichstädt, a mathematician working as a software professional, has taken two images from JunoCam and reprojected them to the same vantage point to enable a direct comparison between the images and show the subtle motions within the atmosphere. By modelling the movement of individual pixels in the images, he has created an animation that extrapolates the swirling evolution of the vortices in the atmosphere.

Eichstädt explains: “This animation represents a ‘feasibility test’. Building on this initial work, we can add in more variables that will give us a more detailed description and physical understanding of Jupiter’s atmosphere.”

Seán Doran, in collaboration with Eichstädt, has created a new composite image of Jupiter as seen by Juno as it swung away from Jupiter’s south pole on 1st April 2018. Because Jupiter was larger than JunoCam’s field of view when the main portion of the image was taken, Eichstädt rendered four other images to the same viewing geometry to reconstruct a mosaic of the whole planet. Doran then processed the composite image to balance and blend the overlapping components, sharpen the contrast, and fill gaps.

I have myself highlighted images by both previously at Behind the Black, here and here and here and here. This press release nicely places both in the limelight at last.

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Asteroid that formed in the inner solar system discovered in Kuiper Belt

9:24 am

Astronomers have discovered a carbonaceous asteroid in the distant Kuiper Belt beyond Pluto, even though it likely formed in the inner solar system.

The asteroid’s existence serves to confirm models of the solar system’s formation that say that the orbits of gas giants migrate inward and outward during the formation process, and as they do so they can fling material out of the inner solar system. This asteroid is the first evidence of this process.

At the same time, the data here is quite slim. They have only found one such asteroid. It could be that it was flung into the Kuiper Belt by other processes. If the formation model is correct, many more such Kuiper Belt asteroids will be eventually be found.

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Astronomers find evidence for thousands of black holes near galaxy center

8:46 am

The uncertainty of science: Using data from the Chandra X-Ray Observatory, astronomers have found evidence suggesting that thousands of stellar-mass black holes might exist circling Sagittarius A* (pronounced A-star), the super-massive black hole at the center of the Milky Way.

Essentially, they found a dozen likely black hole candidates in what they think are X-ray binaries system. From this they extrapolate the number of potential stellar-massed black holes at the center of the galaxy. However,

While the authors strongly favor the black hole explanation, they cannot rule out the possibility that up to about half of the observed dozen sources are from a population of millisecond pulsars, i.e., very rapidly rotating neutron stars with strong magnetic fields.

In other words, this conclusion is very uncertain. Nonetheless, even if half of their candidates are not stellar-mass black holes, the results do suggest that there are a very large number of black holes circling Sagittarius A*. Using this information astronomers will be able to better refine their theories on the formation process for such super-massive black holes.

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Craters, cones, pits, amid endless plains

12:49 pm

Pits, cones, and craters

Cool image time! Buried in the catalog of recent high resolution images from Mars Reconnaissance Orbiter are places on Mars that are inexplicable and fascinating, while also indicative of its vastness. The image on the right, reduced in resolution and cropped to post here, shows us one such place. If you click on the image you can see the full image at high resolution.

The archive posting of this image is titled “Cones near Pits.” As you can see, to the north and east of the pits are some mesas (why they call them cones I do not know).

The pits are unusual, and appear to be some form of collapse. In the larger image several additional mesas can be seen at farther distances, but most of the overall terrain is remarkably flat and featureless, except for numerous small craters that appear either partly buried by dust or significantly eroded.

I am not going to guess at the geology that caused the pits and mesas. What I do want to focus on is the vastness of Mars. This location is on the southern edge of Utopia Basin, the second deepest basin on Mars. It is part of the planet’s endless northern plains, an immense region covering almost half the planet that tends to be at a lower elevation, is relatively smooth, and is thought by some scientists to be evidence of what was once an intermittent ocean. The global map of Mars below indicates the location of the above image with a black cross.
» Read more

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Pluto is a planet

9:51 am

In an op-ed today, the principal investigator for the New Horizons’ mission as well as his co-author for the history of that mission explained in detail why the definition for planet as imposed by the International Astronomical Union (IAU) is flawed and unworkable.

In 2006, the International Astronomical Union (IAU) announced an attempted redefinition of the word “planet” that excluded many objects, including Pluto. We think that decision was flawed, and that a logical and useful definition of planet will include many more worlds.

We find ourselves using the word planet to describe the largest “moons” in the solar system. Moon refers to the fact that they orbit around other worlds which themselves orbit our star, but when we discuss a world like Saturn’s Titan, which is larger than the planet Mercury, and has mountains, dunes and canyons, rivers, lakes and clouds, you will find us — in the literature and at our conferences — calling it a planet. This usage is not a mistake or a throwback. It is increasingly common in our profession and it is accurate.

Most essentially, planetary worlds (including planetary moons) are those large enough to have pulled themselves into a ball by the strength of their own gravity. Below a certain size, the strength of ice and rock is enough to resist rounding by gravity, and so the smallest worlds are lumpy. This is how, even before New Horizons arrives, we know that Ultima Thule is not a planet. Among the few facts we’ve been able to ascertain about this body is that it is tiny (just 17 miles across) and distinctly nonspherical. This gives us a natural, physical criterion to separate planets from all the small bodies orbiting in space — boulders, icy comets or rocky and metallic asteroids, all of which are small and lumpy because their gravity is too weak for self-rounding.

They go on to explain the flawed history of the IAU definition, and how it has simply not been accepted by astronomers and planetary scientists alike. The definition makes no sense, and excludes the thousands of exoplanets discovered orbiting other stars. They also point to a proposed new definition that is simple and admits to reality.

A planet is a sub-stellar mass body that has never undergone nuclear fusion and that has sufficient self-gravitation to assume a spheroidal shape adequately described by a triaxial ellipsoid regardless of its orbital parameters.

Whether or not the stuffed shirts at IAU ever officially endorse this definition, it is the one that human beings are using now, and it will be the one they use into the never-ending future.

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The aging data relay spacecraft orbiting Mars

9:40 am

By the 2020s, NASA and other space agencies sending landers and rovers to Mars will be faced with a data-relay crisis, as the orbiters they presently use to provide communications with the Martian surface are aging, and no replacements are presently planned.

The venerable Mars Global Surveyor (MGS) and Mars Odyssey spacecraft were the first to employ data relay capabilities in the modern era of Mars exploration. They operated as relays for the twin Mars Exploration Rover missions until the arrival of the Mars Reconnaissance Orbiter (MRO) in 2006.

MGS entered into a safe mode in November 2006 and NASA later declared the mission over in January 2007 after the space agency failed to reestablish contact with the aging orbiter. The 12-year-old MRO and 17-year-old Odyssey have served as the primary data relays for Mars surface missions since.

More important, funding for a dedicated communications satellite called NEMO, planned for launch in 2022, has disappeared.

However, funding for NeMO has been largely phased out in favor of directing limited funds towards the development of the Mars Sample Return mission. Mars Sample Return has the primary objective of fetching samples that scientists plan to collect and cache using the Mars 2020 rover currently under development. The current Planetary Science Decadal Survey has listed the flagship sample return mission as the primary objective for NASA’s Mars program in the 2020s, along with requisite funding. The existing fleet of orbiting spacecraft at Mars, while aging, are in generally good health meaning the postponement of a new orbiter will require careful management of existing orbital assets into the next decade.

One of the reasons there is no funding for NEMO is that NASA has had to steal money from its planetary program to fund the cost overruns on the James Webb Telescope. Though this was never admitted publicly, the cuts that the Obama administration imposed on the planetary program were partly to pay for Webb. Thus, not only has that telescope killed almost all of NASA’s entire astrophysics program, it has damaged the planetary program as well.

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Sunspot update for April 2018: Heading into solar minimum

9:00 am

On Sunday NOAA posted its monthly update of the solar cycle, covering sunspot activity for April 2018. Below is my annotated version of that graph.

While there was an uptick in sunspots in April, compared to the almost complete inactivity in March (the least active month for sunspots in a decade), the uptick did little to change the general trend. Sunspot activity is now comparable to what we saw in early 2008 (as indicated by the yellow line). This was just before the arrival of the previous solar minimum, which happened to also be one of the longest and deepest on record.

» Read more

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Volcano or Impact?

11:34 am

Elliptical crater with flow features

Cool image time! Yesterday the Mars Reconnaissance Orbiter (MRO) team released its monthly image dump of more than 500 new photographs, taken by the spacecraft’s high resolution camera. As I have started to do in the past few months, I am reviewing this collection and plan to post a few of the more interesting images over the next month. On the right is the first of this series. I have cropped and reduced the resolution to show here, but you can see the full resolution version if you click on the image.

The MRO team labels this image an “elliptical crater with flow features.” The first impression one gets from the image is that the impact that caused the crater came from the side and hit the ground obliquely, creating the crater’s oval shape and the lava-type flow features in the crater’s floor.

As is almost always the case with Martian geology, beware of first impressions. You need to give any feature both a more detailed look as well as a broader view to have any chance at understanding its context and geology.
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More problems uncovered during testing of the James Webb Space Telescope

8:42 am

During ground tests of the James Webb Space Telescope engineers have discovered an additional quite astonishing problem that will certainly delay the project again.

In a presentation at a meeting of the National Academies’ Space Studies Board here May 3, Greg Robinson, the JWST program director at NASA Headquarters, said some “screws and washers” appear to have come off the spacecraft during recent environmental testing at a Northrop Grumman facility in Southern California.

Technicians found the items after the spacecraft element of JWST, which includes the bus and sunshield but not its optics and instruments, was moved last weekend from one chamber for acoustics tests to another to prepare for vibration testing.

“Right now we believe that all of this hardware — we’re talking screws and washers here — come from the sunshield cover,” he said. “We’re looking at what this really means and what is the recovery plan.” The problem, he said, was only a couple of days old, and he had few additional details about the problem. “It’s not terrible news, but it’s not good news, either,” he said. [emphasis mine]

The absurd spin expressed by the program director above is garbage. This is unbelievable and entirely unacceptable. On spacecraft, especially those that are not planned for in-space maintenance like Webb, screws are routinely sealed with some form of glue so that they will not unscrew themselves during the vibrations of launch. This is standard space engineering and has been for more than a half century.

That some screws came off Webb during testing suggests a quality control problem at Northrop Grumman that is beyond comprehension.

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NASA tests new small fission power plant for future space missions

10:08 am

NASA has successfully completed a full test of a new small fission power plant that it hopes to use in future space missions.

The prototype power system uses a solid, cast uranium-235 reactor core, about the size of a paper towel roll. Passive sodium heat pipes transfer reactor heat to high-efficiency Stirling engines, which convert the heat to electricity.

According to David Poston, the chief reactor designer at NNSA’s Los Alamos National Laboratory, the purpose of the recent experiment in Nevada was two-fold: to demonstrate that the system can create electricity with fission power, and to show the system is stable and safe no matter what environment it encounters. “We threw everything we could at this reactor, in terms of nominal and off-normal operating scenarios and KRUSTY passed with flying colors,” said Poston.

The Kilopower team conducted the experiment in four phases. The first two phases, conducted without power, confirmed that each component of the system behaved as expected. During the third phase, the team increased power to heat the core incrementally before moving on to the final phase. The experiment culminated with a 28-hour, full-power test that simulated a mission, including reactor startup, ramp to full power, steady operation and shutdown.

Throughout the experiment, the team simulated power reduction, failed engines and failed heat pipes, showing that the system could continue to operate and successfully handle multiple failures.

This power plant appears similar in concept to the fission RTG nuclear fuel systems that have been used routinely for decades on unmanned planetary probes such as the two Voyager spacecraft, New Horizons, and on Curiosity. This new system however provides significantly more power, as much as ten kilowatts compared to the approximate two hundred watts provided by RTGs.

Such a system will be essential for future bases on both Mars and the Moon, where solar power is not the best option. I should also add that such a system might possibly have applications here on Earth. Developed properly, it could provide a practical power source for out-of-the-way locations not on the grid. If made cheap enough, it might also provide electrical customers a cheaper and competitive alternative that will allow them to remove themselves from the grid entirely.

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Hubble detects helium in exoplanet atmosphere

2:57 pm

Using the Hubble Space Telescope astronomers have for the first time detected helium in the atmosphere of an exoplanet.

The team made the detection by analysing the infrared spectrum of the atmosphere of WASP-107b [1]. Previous detections of extended exoplanet atmospheres have been made by studying the spectrum at ultraviolet and optical wavelengths; this detection therefore demonstrates that exoplanet atmospheres can also be studied at longer wavelengths.

…WASP-107b is one of the lowest density planets known: While the planet is about the same size as Jupiter, it has only 12% of Jupiter’s mass. The exoplanet is about 200 light-years from Earth and takes less than six days to orbit its host star.

The amount of helium detected in the atmosphere of WASP-107b is so large that its upper atmosphere must extend tens of thousands of kilometres out into space. This also makes it the first time that an extended atmosphere has been discovered at infrared wavelengths. Since its atmosphere is so extended, the planet is losing a significant amount of its atmospheric gases into space — between ~0.1-4% of its atmosphere’s total mass every billion years

The important aspect of this detection is the use of infrared, which gives astronomers another tool to study exoplanets.

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