Tag: science

Schiaparelli landing apparently a failure

8:32 am

This report from russianspaceweb.com provides some details about the apparent landing failure of the European Mars probe Schiaparelli on Wednesday.

The very preliminary analysis of the data revealed a number of serious problems in the final phase of the parachute descent. The telemetry showed that the back heat shield holding the parachute had been ejected earlier than scheduled — 50 seconds instead of 30 seconds before the touchdown. Also, the lander was apparently descending at a speed higher than planned. There were also indications that the soft-landing engines had fired for only three or four seconds and all communications from the lander were cut 19 seconds later, or shortly before touchdown. By that time, Schiaparelli’s landing radar had been activated.

It appears the parachutes were released too soon so that they did not function properly and slow the spacecraft down enough. When the retro-rockets fired the spacecraft was probably also closer to the ground than planned and falling too fast, so they failed to stop it from impacting the surface hard and prematurely.

13 comments

Fate of Schiaparelli remains unknown

4:06 pm

While Europe’s Trace Gas Orbiter has successfully gone into orbit around Mars, it remains unknown whether the lander Schiaparelli was able today to land successfully on the surface.

The carrier signal from Schiaparelli recorded by Mars Express abruptly ended shortly before landing, just as the beacon tone received by a ground-based radio telescope in India stopped in real-time earlier today.

Paolo Ferri, head of ESA’s mission operations department, just gave an update on the situation. “We saw the signal through the atmospheric phase — the descent phase. At a certain point, it stopped,” Ferri said. “This was unexpected, but we couldn’t conclude anything from that because this very weak signal picked up on the ground was coming from an experimental tool.

“We (waited) for the Mars Express measurement, which was taken in parallel, and it was of the same kind. It was only recording the radio signal. The Mars Express measurement came at 1830 (CEST) and confirmed exactly the same: the signal went through the majority of the descent phase, and it stopped at a certain point that we reckon was before the landing.

“There could be many many reasons for that,” Ferri said. “It’s clear these are not good signs, but we will need more information.”

11 comments

Juno enters safe mode prior to Jupiter close approach

1:25 pm

Because Juno entered safe mode prior to its close approach of Jupiter today, no science data was gathered.

NASA’s Juno spacecraft entered safe mode Tuesday, Oct. 18 at about 10:47 p.m. PDT (Oct. 19 at 1:47 a.m. EDT). Early indications are a software performance monitor induced a reboot of the spacecraft’s onboard computer. The spacecraft acted as expected during the transition into safe mode, restarted successfully and is healthy. High-rate data has been restored, and the spacecraft is conducting flight software diagnostics. All instruments are off, and the planned science data collection for today’s close flyby of Jupiter (perijove 2), did not occur. “At the time safe mode was entered, the spacecraft was more than 13 hours from its closest approach to Jupiter,” said Rick Nybakken, Juno project manager from NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We were still quite a ways from the planet’s more intense radiation belts and magnetic fields. The spacecraft is healthy and we are working our standard recovery procedure.”

This problem, combined with the thruster valve problem that prevented engineers from putting the spacecraft into its proper 14-day science orbit today, is significantly delaying science operations. They will not be able to adjust the orbit again until its next close approach December 11 (assuming the thruster problem has been solved by then), and until then it will also not be able to do much science.

Leave a comment

Landslides on Charon

8:40 am

Landslide on Charon

Images from New Horizons have detected evidence of past avalanches on Pluto’s largest moon, Charon. The image on the right is a reduced version of a perspective view created using data from various instruments.

This perspective view of Charon’s informally named “Serenity Chasm” consists of topography generated from stereo reconstruction of images taken by New Horizons’ Long Range Reconnaissance Imager (LORRI) and Multispectral Visible Imaging Camera (MVIC), supplemented by a “shape-from-shading” algorithm. The topography is then overlain with the PIA21128 image mosaic and the perspective view is rendered. The MVIC image was taken from a distance of 45,458 miles (73,159 kilometers) while the LORRI picture was taken from 19,511 miles (31,401 kilometers) away, both on July 14, 2015.

close-up of landslide

To the left is a close-up taken from the annotated image. You can see the slump materials at the base of the mountain left behind after the material slide down the mountain. It is not clear whether it is Charon’s lower gravity and alien composition and environment (very very very cold) that makes this look more muddy than one would expect, or whether it is because of the limited resolution of the original image and the modeling to create the oblique version.

One comment

Comet 67P/C-G slowly breaking apart

5:56 pm

A comparison of Rosetta images before and after Comet 67P/C-G’s close approach to the sun last year found new fractures and an enlargement of older fractures.

The fractures appear to be developing as forces subtly bend the comet to and fro, Stubbe Hviid, a planetary scientist at the German Aerospace Center Institute of Planetary Research in Berlin, reported October 17 in a press conference at a meeting of the American Astronomical Society’s Division for Planetary Sciences. Hviid and colleagues combined maps from Rosetta with computer simulations of all the forces at work within the comet to determine how the cracks develop. They found that the two bulbous ends rock in opposite directions as the comet spins, flexing the neck and creating severe stress. Because the comet isn’t held together strongly — it’s a conglomeration of dust and ice not much stickier than snow, Hviid said — the neck is starting to break. After a few hundred more years, he said, the comet could fold itself in half as the two lobes snap apart and smoosh together.

Leave a comment

Active volcano on Venus?

5:18 pm

The uncertainty of science: A new analysis of past data from a variety of Venus orbiters suggests that at least one volcano is active there.

The review of old data from the Magellan and Venus Express orbiters suggests that some lava flows on the volcano’s slopes are fresh, though how fresh remains unknown. However, computer models and the detection of excess heat by Venus Express on the mountain’s eastern slopes adds weight to the theory that the volcano is spewing out lava.

Leave a comment

The clouds of hot Jupiter exoplanets

11:24 am

Exoplanet clouds

Cool image time! The image on the right, reduced to show here, provides an overall summary of what astronomers know about the atmospheres of many gas giant exoplanets that also orbit very close to their suns and are tidally locked. The view is of the planet hemisphere facing away from the star, which is also where most of the clouds are thought to be. These results come from Kepler data combined with computer modeling, and show what scientists thinks happens with different cloud compositions at different temperatures.

Link fixed!

2 comments

Mars rover update

10:49 am

Emily Lakdawalla at Sky & Telescope today provides an update of the two Mars rovers, but takes a different approach than I have. While I have been focusing on tracking where the rovers are going and what they are doing, she gives a very nice overview of each rovers’ condition, what instruments continue to work and what have failed.

I myself have not done a new rover update since October 6 for several reasons. First and foremost, neither rover has gone anywhere since my last report. Opportunity is still sitting on Spirit Mound, studying the rocks there. Curiosity is still in the flats south of Murray Buttes, preparing to drill another hole.

Secondly, there was a delay this past weekend in downloading data, especially from Curiosity. I strongly suspect that the delay was simply because the Deep Space Network was being used to help with communications between Europe and its ExoMars probes, now set to arrive at Mars tomorrow. When the lander Schiaparelli separated from the orbiter on Sunday they had had some initial communications problems, and it is likely that though ESA was using its own deep space network, they also enlisted ours to help.

Thirdly, I have been very tied up trying to finish my cave project monograph. This is done now, so I finally have more time to work on Behind the Black.

Leave a comment

New object found beyond Kuiper belt

10:20 am

Worlds without end: Astronomers have discovered another object far beyond Pluto and in an elliptical orbit whose farthest point is 1,450 astronautical units, or about 135 billion miles from the Sun.

This is not the same object recently discovered in a somewhat similar elliptical orbit.

Astronomers right now do not understand the formation process that put these objects in these distant orbits. Some think the objects might have originally come from the Oort cloud that is even farther out from the Sun, their orbits shifted by the as-yet undiscovered Planet X that astronomers love to talk about, but others are skeptical. Since no one has ever actually detected anything in the the theorized Oort Cloud, it is also possible that it does not exist as presently theorized, and might actually be a more scattered collection of objects, like these new discoveries, that travel both farther and closer to the Sun.

One comment

Mars in ultraviolet

9:47 am

Data from the Mars orbiter MAVEN have given scientists their first detailed look at the red planet in ultraviolet wavelengths.

New global images of Mars from NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission being led by CU Boulder show the ultraviolet glow from the Martian atmosphere in unprecedented detail, revealing dynamic, previously invisible behavior.

They include the first images of “nightglow” that can be used to show how winds circulate at high altitudes. Additionally, dayside ultraviolet imagery from the spacecraft shows how ozone amounts change over the seasons and how afternoon clouds form over giant Martian volcanoes. The images were taken by the Imaging UltraViolet Spectrograph (IUVS) on MAVEN.

The build-up of clouds over Mars’ four big volcanoes is especially interesting, since it is thought this water vapor likely comes from underground ice left over from glaciers that were once on the mountains’ slopes. A very short video of that build up can be seen, below the fold.
» Read more

Leave a comment

ExoMars 2016 in detail

8:14 am

This Nature article provides a nice summary of the European/Russian ExoMars 2016 mission that on Wednesday will try to place a lander on Mars as well as put an orbiter in orbit.

Neither probe is going to provide many exciting photos. The orbiter, dubbed boringly the Trace Gas Orbiter, is designed to study Mars’ atmosphere, while the lander, Schiaparelli, is essentially a technology test mission for planning and designing what Europe and Russia hope will be a more ambitious lander/orbiter mission in 2020.

Anyone expecting spectacular pictures from Schiaparelli itself might be disappointed — photos will be limited to 15 black-and-white shots of the Martian surface from the air, intended to help piece together the craft’s trajectory. No photos will be taken on the surface, because the lander lacks a surface camera.

Schiaparelli’s instruments will study the Martian atmosphere, including the possible global dust storm that might happen this month but so far has not yet appeared. The instruments will also be able to detect lightning, should it exist on Mars.

One comment

Problems with Juno’s main engine

6:18 pm

Valve problems detected during Juno’s orbital insert around Jupiter has caused engineers to delay the October 19 engine burn that would have lowered the probe’s orbit around Jupiter.

Mission managers for NASA’s Juno mission to Jupiter have decided to postpone the upcoming burn of its main rocket motor originally scheduled for Oct. 19. This burn, called the period reduction maneuver (PRM), was to reduce Juno’s orbital period around Jupiter from 53.4 to 14 days. The decision was made in order to further study the performance of a set of valves that are part of the spacecraft’s fuel pressurization system. The period reduction maneuver was the final scheduled burn of Juno’s main engine. “Telemetry indicates that two helium check valves that play an important role in the firing of the spacecraft’s main engine did not operate as expected during a command sequence that was initiated yesterday,” said Rick Nybakken, Juno project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California. “The valves should have opened in a few seconds, but it took several minutes. We need to better understand this issue before moving forward with a burn of the main engine.”

Because of this, they will instead use this next close approach to Jupiter to do pure science, something that they would not have done during the engine burn. Though this is a good example of turning lemons into lemonade, it will not be a good thing if Juno can never reduce its orbit to 14 days. A 53 day orbit will mean that they can only do good research every two months, and will seriously limit what they can learn over the long run.

One comment

Kaguya data released at last

9:06 am

Seven years after the mission ended Japan has finally released the full catalog of images and videos taken by its lunar orbiter Kaguya.

No explanation for the long delay has been provided. Overall, this is just another example of what to me appears to be a bloated, bureaucratic, and slow to move Japanese space program. Their rockets are expensive, their planetary probes have had repeated problems, and they seem to be very uninterested in stepping up their game to compete in the increasingly competitive international race to explore and settle the solar system. That it took them more than seven years to release this data is quite shameful.

Leave a comment

ExoMars 2016 bearing down on Mars

8:59 am

This article provides a detailed look at Sunday’s arrival of ExoMars 2016 at Mars.

If all goes right the Schiaparelli lander will soft land on the surface while the Trace Gas Orbiter will enter an initial 185 by 60,000 mile orbit, which will slowly be adjusted so that by January it can begin its atmospheric research.

Though the Russian contribution to this mission was only the rocket that sent it to Mars, if the mission succeeds it will be the first time any Mars mission with major Russian participation has succeeded. The failure rate for any Russian effort to go to Mars has been 100%. And it hasn’t been because the missions have been particularly difficult. The majority of their failures occurred in the 1960s and 1970s, even as they were very successfully completing much harder lander missions to Venus.

It has almost as if there is a curse against any Russian attempt to visit the Red Planet. Hopefully, that curse will finally be broken on Sunday.

One comment

New power source for planetary missions?

9:53 am

Research at JPL has developed new materials called skutterudites that have the potential of increasing the efficiency and power output of the radioisotope electric generators used on deep space missions where solar power will not work.

The new eMMRTG would provide 25 percent more power than Curiosity’s generator at the start of a mission, according to current analyses. Additionally, since skutterudites naturally degrade more slowly that the current materials in the MMRTG, a spacecraft outfitted with an eMMRTG would have at least 50 percent more power at the end of a 17-year design life than it does today.

“Having a more efficient thermoelectric system means we’d need to use less plutonium. We could go farther, for longer and do more,” Bux said.

This being NASA research, they are moving somewhat slowly in testing and confirming whether these new materials will work. They hope that after passing further reviews in 2017 and 2018 the agency might finally approve their use in subsequent missions.

3 comments

Ten times more galaxies than previously believed

9:44 am

The uncertainty of science: A new analysis from Hubble and other telescope data suggests that the universe actually contains ten times more galaxies than previously estimated, several trillion instead of the past estimate of 100 to 200 billion.

I would not bet much money on this conclusion. I suspect that further research will find even more galaxies, since our deep observations of the universe are at the moment confined to a mere handful of Hubble deep field images that cover only a few tiny specks of space.

This new analysis however did confirm previous estimates that suggest the universe has evolved and changed significantly over time.

In analysing the data the team looked more than 13 billion years into the past. This showed them that galaxies are not evenly distributed throughout the Universe’s history. In fact, it appears that there were a factor of 10 more galaxies per unit volume when the Universe was only a few billion years old compared with today. Most of these galaxies were relatively small and faint, with masses similar to those of the satellite galaxies surrounding the Milky Way.

These results are powerful evidence that a significant evolution has taken place throughout the Universe’s history, an evolution during which galaxies merged together, dramatically reducing their total number. “This gives us a verification of the so-called top-down formation of structure in the Universe,” explains Conselice.

5 comments

Breakthrough increases plant yields by one third

9:29 am

Plant scientists have found a way to encourage plants to better use atmospheric nitrogen, thus increasing yields by more than one third.

For years, scientists have tried to increase the rate of nitrogen fixation in legumes by altering rhizobia bacterioid function or interactions that take place between the bacterioid and the root nodule cells.

Tegeder took a different approach: She increased the number of proteins that help move nitrogen from the rhizobia bacteria to the plant’s leaves, seed-producing organs and other areas where it is needed. The additional transport proteins sped up the overall export of nitrogen from the root nodules. This initiated a feedback loop that caused the rhizobia to start fixing more atmospheric nitrogen, which the plant then used to produce more seeds. “They are bigger, grow faster and generally look better than natural soybean plants,” Tegeder said. “Some evidence we have suggests they might also be highly efficient under stressful conditions like drought.”

The technique not only produces healthier plants and more seeds, it reduces the need for fertilizer, the overuse of which can be an environmental issue.

3 comments

TMT considers alternative sites to Hawaii

9:36 am

Faced with a continuing legal battle to build the Thirty Meter Telescope (TMT), the consortium running is now seriously considering alternative sites.

Potential Northern Hemisphere sites include San Pedro Mártir in Baja California in Mexico and Roque de los Muchachos on La Palma, a Spanish island off the Atlantic coast of Morocco. “Our friends in La Palma are pushing hard” to get the TMT, says Matt Mountain, president of the Association of Universities for Research in Astronomy in Washington, D.C. But neither alternative matches the seeing conditions on Mauna Kea, and they would bring extra cost and complication. The project has already ruled out sites in the Himalayas, put forward by India and China—both TMT partners along with the United States, Japan, and Canada—because they are too far from ports and have short construction seasons.

The TMT governors are expected to choose their top alternative site later this month. Regardless of what happens in Hawaii, the governors have vowed to start construction—on Mauna Kea or elsewhere—no later than April 2018.

It is clear that Mauna Kea in Hawaii is the best location. Unfortunately, they are faced with the reality that there might be years of delays before they ever get permission to build, if they get permission at all.

5 comments

A large Kuiper Belt object discovered

3:55 pm

Astronomers have detected a new but very distant Kuiper Belt object.

For now, his team knows little more about their distant discovery other than its orbit and apparent brightness. Given its distance, however, the object should be sizable — anywhere from 400 km across (if its surface is bright and 50% reflective) to 1,200 km (if very dark and 5% reflective). If its true size edges toward the larger end of this range, then 2014 UZ224 would likely qualify for dwarf-planet status.

Fortunately, we should have a much better estimate of the object’s size very soon. Gerdes has used the ALMA radio-telescope array to measure the heat radiating from 2014 UZ224, which can be combined with the optical measurements to yield its size and albedo.

The object has a very eccentric 1,140 year orbit, coming as close to the sun as Pluto at its closest and almost five times farther away at its furthest.

Note: I have changed the article title because this new object is almost certainly not bigger the Pluto, as one of my readers pointed out.

3 comments

Cosmic rays a threat to Mars travel

8:45 am

The uncertainty of science: New research using rats has found that cosmic rays might damage human brains during a long mission to and from Mars.

Radiation oncologist Charles Limoli and his colleagues at the University of California Irvine bombarded mice and rats with low-doses of ionized oxygen or titanium. These charged particles have similar energies to those of cosmic rays that can pass right through the shielding on spacecraft. The dosage levels that the researchers used were similar to what astronauts would be exposed to during a three-year round-trip mission to Mars, Limoli says.

The researchers looked at the prefrontal cortex, the brain region linked to decision-making, executive function, and long-term memory. They saw significant damage and inflammation in the brains of exposed animals as long as six months after the exposure. The radiation damaged the tiny branches on neurons that help transmit electric signals to the nerve cell body. This led to a loss in learning and memory. The exposed animals performed poorly on behavioral tests that measure intelligence, and they showed higher, constant anxiety levels.

Though the uncertainties here are enormous, the research here has essentially discovered the obvious. The radiation experienced during a long interplanetary voyage is unhealthy, and any interplanetary vessel for carrying humans on such a voyage must be designed with sufficient shielding to protect its passengers. That this research has proven that cosmic rays are a threat also means that providing a ship with a safe room where passengers can take refuge during solar storms is not sufficient. Cosmic rays are random and come at all times in an unpredictable manner. The research suggests that the shielding will have to protect the ship’s entire living quarters.

The payload weight requirements for any rocket that will launch the first interplanetary ships just went up significantly. This means that space stations we have been building (Mir, ISS, and Tiangong) are not even close to sufficient for interplanetary travel, and need significant redesign to make them work. This also means that human interplanetary travel will require cost-efficient heavy lift rockets such as the Falcon Heavy.

19 comments

Sunspot ramp down resumes

9:31 am

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

September 2016 Solar Cycle graph

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

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

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

3 comments

Predicting the next Martian global dust storm

5:22 pm

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

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

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

5 comments

The mystery of Tabby’s star deepens

7:07 am

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

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

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

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

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

14 comments

Curiosity moves on

8:55 pm

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

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

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

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

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

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

Leave a comment

Dark matter unnecessary?

9:06 pm

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

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

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

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

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

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

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

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

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

57 comments

Keeping the Deep Space Network working

9:12 am

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

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

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

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

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

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

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

11 comments

The interior of Comet 67P/C-G

8:56 am

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

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

Leave a comment
1 … 131 132 133 134 135 … 260