Tag: science

Rosetta’s finale set for September 30

8:41 am

The Rosetta science team has set September 30th as the date when they will complete the spacecraft’s mission with a controlled descent onto Comet 67P/C-G’s surface.

Unlike in 2011, when Rosetta was put into a 31-month hibernation for the most distant part of its journey, this time it is riding alongside the comet. Comet 67P/Churyumov-Gerasimenko’s maximum distance from the Sun (over 850 million km) is more than Rosetta has ever journeyed before. The result is that there is not enough power at its most distant point to guarantee that Rosetta’s heaters would be able to keep it warm enough to survive.

Instead of risking a much longer hibernation that is unlikely to be survivable, and after consultation with Rosetta’s science team in 2014, it was decided that Rosetta would follow its lander Philae down onto the comet. The final hours of descent will enable Rosetta to make many once-in-a-lifetime measurements, including very-high-resolution imaging, boosting Rosetta’s science return with precious close-up data achievable only through such a unique conclusion. Communications will cease, however, once the orbiter reaches the surface, and its operations will then end.

The decision to end the mission this way makes great sense. I only question their decision to purposely end all communications upon impact. Though it is likely that communications will be lost anyway, wouldn’t it be better to try to get data back, like the scientists did with the American NEAR spacecraft when it touched down on the asteroid Eros at the end of its mission?

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Our limited understanding of the Martian climate through time

11:55 pm

The uncertainty of science: Annual Reviews periodically publishes papers providing a detailed scientific review of the present state of knowledge in a variety of fields. They do this by collecting the papers in volumes focused on general areas of research, such as Astronomy and Astrophysics, Plant Biology, and even Sociology.

Today I received the announcement of the publication of the 44th volume of the Annual Review of Earth and Planetary Sciences, listing the volume’s table of contents. While there were many interesting papers on a variety of planetary subjects that interested me (“The climate of Titan,” “Impacts of Climate Change on the Collapse of Lowland Maya Civilization,” and “The Lakes and Seas of Titan”), one paper in particular, entitled “The climate of early Mars”, intrigued me enough after reading the abstract to download it and read it in its entirely. (As a science journalist I have free access to the full text of these papers. While the abstract is free to all, if you wish to read the full text you need to either buy it, or visit a university library that subscribes to each particular series.)

As a review I found the paper quite fascinating. It provided an excellent overview of our present understanding of Mars’s climate history, information that is especially useful to me in reporting on the results from the various Martian orbiters and rovers, as it gives me a wider context and allows me to better understand and analyze each press announcement. This in turn allows me to distinguish between a real discovery of some importance and a garbage press release that is really nothing more than a sales pitch for more funding.

The bottom line of this paper however is this: We know without doubt, based on a lot of geological evidence, that approximately 3 to 4 billion years ago liquid water existed on the Martian surface, leaving behind complex valley drainage networks similar to those created by flowing water on Earth. In addition, the data from the rovers has also found evidence, clays and other minerals, that could only have formed if water once flowed on the surface. What we don’t know is how that liquid water could have existed. The data so far does not provide any clear mechanism for warming the climate enough as well as producing a thick enough atmosphere to allow liquid water to flow. To quote the paper:

In summary, no single mechanism is currently accepted as the cause of anomalous warming events on early Mars.

The data also suggests that an ocean on Mars was unlikely, though not impossible. Instead, it appears that if any warming events occurred to produce liquid water, they were temporary and short-lived. What caused those warming events, however, remains a scientific mystery.

The paper also made clear once again the complexity of climate science, and how difficult it is to develop climate models that explain the geological evidence, not just on Mars, but on Earth as well. As the paper also noted, “Just like the climate of Earth today, the ancient climate of Mars was probably complex, with multiple factors contributing to the mean surface temperature.” And like the climate of Earth, many of those multiple factors remain uncertain and poorly understood. It will be many years before we really understand how Mars got to be the way it is.

Likely, to figure it out we will have to go there ourselves and poke around with our own hands.

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Dawn data suggests recent hydrothermal activity on Ceres

11:38 am

New data from Dawn now suggests that the bright spot in Occator Crater on Ceres contains the highest concentration of carbonate materials found so far outside of Earth, and was caused by recent hydrothermal activity.

De Sanctis’ study finds that the dominant mineral of this bright area is sodium carbonate, a kind of salt found on Earth in hydrothermal environments. This material appears to have come from inside Ceres, because an impacting asteroid could not have delivered it. The upwelling of this material suggests that temperatures inside Ceres are warmer than previously believed. Impact of an asteroid on Ceres may have helped bring this material up from below, but researchers think an internal process played a role as well.

More intriguingly, the results suggest that liquid water may have existed beneath the surface of Ceres in recent geological time. The salts could be remnants of an ocean, or localized bodies of water, that reached the surface and then froze millions of years ago.

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Geologists discover giant field of underground helium in Tanzania

2:53 pm

Geologists have discovered a gigantic new field of underground helium gas, located in Tanzania’s Rift Valley.

Researchers figure there’s about 54 billion cubic feet of helium in just one section of the valley. To put that in context, the Federal Helium Reserve in Texas, which supplies more than 40% of domestic helium needs and contains about 30% of the world’s total helium supply, right now holds about 24.2 billion cubic feet, per Live Science.

The discovery is also important in that it wasn’t an accident. The geologists located the helium based on their theories of where they should find it.

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Moon discovered orbiting Kuiper Belt Object Makemake

6:57 pm

Worlds without end: Astronomers have discovered a moon orbiting Makemake, the fouth largest object in the Kuiper Belt.

A nearly edge-on orbital configuration helped it evade detection, placing it deep within the glare of the icy dwarf during a substantial fraction of its orbit. Makemake is one of the largest and brightest known Kuiper Belt Objects (KBOs), second only to Pluto. The moon is likely less than 100 miles wide while its parent dwarf planet is about 870 miles across. Discovered in 2005, Makemake is shaped like football and sheathed in frozen methane.

Tracking this moon’s orbit will help astronomers get a better understanding of Makemake itself, whose oblong shape has baffled them since its discovery.

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Juno closing in on Jupiter

10:52 am

Jupiter from Juno

On Friday the Juno science team released a new image of Jupiter taken by the spacecraft from about 6.8 million miles away.

The reduced resolution image on the right is cropped but with the colors enhanced to bring out the four Galilean moons, Ganymede, Callisto, Europa, and Io. The website notes that “Juno is approaching over Jupiter’s north pole, affording the spacecraft a unique perspective on the Jovian system. Previous missions that imaged Jupiter on approach saw the system from much lower latitudes, closer to the planet’s equator.”

Rendezvous and orbital insertion happens on July 4.

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Ceres’s brightest spot

2:30 pm

Brightest Spot in Occator Crater on Ceres

Cool image time: While I was in Washington the Dawn science team released a very nice close-up image of the bright spots inside Occator Crater on Ceres. On the right is a cropped version which focuses solely on the central brightest spot. The spot appears to overlie a central dome with a depression in the middle. Other data says the spot is the low area in the crater, and the linear cracks that radiate away as well as in concentric rings around the spot suggest that this central area has subsided, causing those cracks.

Make sure you look at the full image, as it includes the other smaller spots that are also inside Occator.

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Data manipulation at U.S. Geological Survey science lab

11:05 am

A federal lab has been shuttered after an investigation revealed almost 20 years of data manipulation and scientific misconduct.

The inorganic section of the U.S. Geological Survey’s (USGS) Energy Geochemistry Laboratory in Lakewood, Colo. manipulated data on a variety of topics – including many related to the environment – from 1996 to 2014. The manipulation was caught in 2008, but continued another six years.

“It’s astounding that we spend $108 million on manipulated research and then the far-reaching effects that that would have,” Rep. Bruce Westerman said at a House Natural Resources subcommittee hearing. “We know how research multiples and affects different parts of our society and our economy and … if you’re working off of flawed data it definitely could be in a bad way.”

The inspector general report [pdf] is very vague about the specific acts of data manipulation and misconduct, which is not surprising since this specific inspector general has herself been accused of “politicized IG investigations, pulling punches in trying to avoid upsetting political appointees.”

From what I can gather, the results from a mass spectrometer, used to identify the chemical make-up of samples, were repeatedly faked by the individuals who operated it. The research “predominantly affected coal and water quality research and related assessments.” It is however unclear whether politics played a part in this misconduct, or whether it was merely incompetence. I suspect the former, especially because the Obama-appointed inspector general went out of her way to avoid describing the misconduct in detail, and because it continued for so long, even after it was first discovered in 2008.

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Science elites move to block UK exit from EU

10:29 am

A statement today from the UK’s Royal Astronomical Society, reacting to yesterday’s vote to leave the European Union, calls for the government to do whatever it can to nullify that exit.

Professor John Zarnecki, the President of the Royal Astronomical Society, commented: “We must remember that whatever happens, science has no boundaries. It is vital that we do not give the message, particularly to our younger colleagues, in the UK and beyond that our country is not a good place in which to do scientific research, however uncertain the economic and political environment is.

“I have been privileged during my career to have worked in a research environment in Europe which has had few borders for either people or ideas. We must strive to make sure that these rights are not taken away – this would be enormously to the detriment of UK society.”

The statement includes a laundry list of benefits that membership in the EU brings scientists, including lots of funding to pay the salaries of these scientists. The statement also insists that all these benefits must be maintained, despite the will of the electorate.

While many of these benefits (easy travel between nations) are beneficial and a reason to have a European Union, the electorate understood that the benefits have been increasingly outweighed by the heavy regulatory burden imposed by the EU, with no democratic recourse allowed.

Articles in the science journals Science and Nature, here, here, and here, also note the distress and opposition by scientists to yesterday’s vote.

This unwillingness of the elite community to accept the will of the public is part and parcel to the same bubble I found in Washington when I attended the CNAS conference. Unfortunately, I see no evidence of a willingness in the elite community to bend at all to the will of the general public, meaning that we can only expect the conflict between the top and the bottom to intensify in the coming years. The question will be whether our institutions of democracy will be able to withstand that battle, especially when those in power continue to find their power being attacked from below.

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Saturn from Cassini

10:40 am

Saturn's rings

Cool image time! The image on the right, reduced in resolution to post here, shows how, because of the seasonal tilt of Saturn, the shadow of its rings is now cover much of the gas giant’s southern hemisphere.

When NASA’s Cassini spacecraft arrived at Saturn 12 years ago, the shadows of the rings lay far to the north on the planet. As the mission progressed and seasons turned on the slow-orbiting giant, equinox arrived and the shadows of the rings became a thin line at the equator. This view looks toward the sunlit side of the rings from about 16 degrees above the ring plane. The image was taken in red light with the Cassini spacecraft wide-angle camera on March 19, 2016.

We will continue to get from Cassini increasingly beautiful images of Saturn and its rings as the spacecraft positions itself better for its final flight down into the planet’s atmosphere.

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Hubble spots new dark storm on Neptune

10:32 am

The Hubble Space Telescope has imaged a developing new dark spot storm on Neptune.

New images obtained on May 16, 2016, by NASA’s Hubble Space Telescope confirm the presence of a dark vortex in the atmosphere of Neptune. Though similar features were seen during the Voyager 2 flyby of Neptune in 1989 and by the Hubble Space Telescope in 1994, this vortex is the first one observed on Neptune in the 21st century. The discovery was announced on May 17, 2016, in a Central Bureau for Astronomical Telegrams (CBAT) electronic telegram by University of California at Berkeley research astronomer Mike Wong, who led the team that analyzed the Hubble data.

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New model for Enceladus’s subsurface ocean

4:03 pm

A new model proposes that the subsurface liquid water ocean of Saturn’s moon Enceladus is possible only 3 miles below the surface near its south pole.

In order to reconcile the different constraints [created by the known data], the researchers propose a new model in which the top two hundred meters of the ice shell acts like an elastic shell. According to this study, Enceladus is made up successively of a rocky core with a radius of 185 km, and an internal ocean approximately 45 km deep, isolated from the surface by an ice shell with a mean thickness of around 20 km, except at the south pole where it is thought to be less than 5 km thick. In this model, the ocean beneath the ice makes up 40% of the total volume of the moon, while its salt content is estimated to be similar to that of Earth’s oceans.

Need I mention that this is only a computer model, and should therefore be considered with great skepticism?

Posted from warm and dry Tucson, Arizona, where I am home at last!

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Pluto might have subsurface liquid water ocean

9:52 pm

An analysis of the data sent back from New Horizons strongly suggests that Pluto might still have a liquid ocean of water beneath its surface.

The pictures New Horizons sent back from its close encounter with the Kuiper Belt’s most famous denizen showed that Pluto was much more than a simple snowball in space. It has an exotic surface made from different types of ices — water, nitrogen and methane. It has mountains hundreds of meters high and a vast heart-shaped plain. It also has giant tectonic features — sinuous faults hundreds of kilometers long as deep as 4 kilometers. It was those tectonic features that got scientists thinking that a subsurface ocean was a real possibility for Pluto. “What New Horizons showed was that there are extensional tectonic features, which indicate that Pluto underwent a period of global expansion,” Hammond said. “A subsurface ocean that was slowly freezing over would cause this kind of expansion.”

Scientists think that there may have been enough heat-producing radioactive elements within Pluto’s rocky core to melt part of the planet’s ice shell. Over time in the frigid Kuiper belt, that melted portion would eventually start to refreeze. Ice is less dense than water, so when it freezes, it expands. If Pluto had on ocean that was frozen or in the process of freezing, extensional tectonics on the surface would result, and that’s what New Horizons saw.

I must emphasize that this result has a great deal of uncertainty. Nonetheless, it suggests once again that we might liquid water in space in a lot of places we never expected or imagined.

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Kelly describes medical issues from weightlessness

8:50 am

In prepared remarks to a congressional subcommittee today, astronaut Scott Kelly described the medical problems he has experienced since returning from his 340 day mission on ISS.

Kelly claimed in these remarks that weightlessness caused permanent effects (which this news article decides to emphasize), but I think that might be an overstatement. None of the specific problems he experienced appear to be permanent ones, and in my interviews with Russian astronauts who stayed even longer on Mir they noted no permanent effects. One did say however that the recovery time tended to match the mission time, so that if you spent a year in space it took a year to completely recover. Kelly has only been back about three months, so his recovery is certainly not over yet.

Update: Kelly’s remarks were part of a hearing promoting legislation that would give astronauts lifetime medical coverage from the government. Thus, there is a bit of lobbying going on here.

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Newly discovered asteroid quasi-moon of Earth

11:41 pm

A newly discovered asteroid has a solar orbit that makes it Earth’s constant companion.

As it orbits the sun, this new asteroid, designated 2016 HO3, appears to circle around Earth as well. It is too distant to be considered a true satellite of our planet, but it is the best and most stable example to date of a near-Earth companion, or “quasi-satellite.”

“Since 2016 HO3 loops around our planet, but never ventures very far away as we both go around the sun, we refer to it as a quasi-satellite of Earth,” said Paul Chodas, manager of NASA’s Center for Near-Earth Object (NEO) Studies at the Jet Propulsion Laboratory in Pasadena, California. “One other asteroid — 2003 YN107 — followed a similar orbital pattern for a while over 10 years ago, but it has since departed our vicinity. This new asteroid is much more locked onto us. Our calculations indicate 2016 HO3 has been a stable quasi-satellite of Earth for almost a century, and it will continue to follow this pattern as Earth’s companion for centuries to come.”

The asteroid is thought to be between 120 to 300 feet across.

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Another gravity wave detected by LIGO

1:12 pm

The LIGO gravitational wave detector has detected its second gravitational wave, thought to come from the merger of two black holes.

The new observation came at 3:38.53 Coordinated Universal Time on 26 December 2015—late on Christmas day at LIGO’s detectors in Livingston, Louisiana, and Hanford, Washington. As in the first event, the detectors sensed an oscillating stretching of space-time, the signal, according to Einstein’s 
general theory of relativity, of massive objects in violent motion. Computer modeling indicated that its source was two black holes spiraling together about 1.4 billion light-years away. (LIGO researchers had seen a weaker signal on 12 October 2015 that may be a third black hole merger.)

Note the last sentence in the quote above. They might have had a third detection, but are uncertain enough to have not claimed it as one.

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Next China lunar lander aimed for farside south pole

5:28 pm

The competition heats up: China announced plans today to send its next lunar lander, Chang’e 4, to the Moon’s farside south pole in 2018.

The lander of Chang’e-4 will be equipped with descent and terrain cameras, and the rover will be equipped with a panoramic camera, he said. Like China’s first lunar rover Yutu, or Jade Rabbit, carried by Chang’e-3, the rover of Chang’e-4 will carry subsurface penetrating radar to detect the near surface structure of the moon, and an infrared spectrometer to analyze the chemical composition of lunar samples.

But unlike Chang’e-3, the new lander will be equipped with an important scientific payload especially designed for the far side of the moon: a low-frequency radio spectrometer. “Since the far side of the moon is shielded from electromagnetic interference from the Earth, it’s an ideal place to research the space environment and solar bursts, and the probe can ‘listen’ to the deeper reaches of the cosmos,” Liu said.

The U.S. had been in the lead in the land rush to gain dominance in the possibly water-rich lunar south pole. We apparently have lost this lead with decision of President Obama and Congress to focus elsewhere, either the asteroids or Mars.

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Curiosity heads south

8:53 am

After four years of southwest travel to skirt a large dune field at the base of Mount Sharp, Curiosity has finally turned due south to aim directly up the mountain.

“Now that we’ve skirted our way around the dunes and crossed the plateau, we’ve turned south to climb the mountain head-on,” said Curiosity Project Scientist Ashwin Vasavada, of NASA’s Jet Propulsion Laboratory, Pasadena, California. “Since landing, we’ve been aiming for this gap in the terrain and this left turn. It’s a great moment for the mission.”

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