Tag: science

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.

Leave a comment

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.

Leave a comment

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!

One comment

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.

Leave a comment

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.

6 comments

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.

3 comments

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.

9 comments

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.

One comment

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.”

One comment

Pluto’s jagged shores

10:43 am

Pluto's jagged shoreline

Cool image time! The picture on the right, taken by New Horizons during its July 2015 flyby and cropped and reduced here, shows the reddish hues of the Krun Macula dark region along the shore of Pluto’s vast nitrogen ice plains. The hillsides here rise about a mile and a half above both the plains and the valleys, making them deeper than the Grand Canyon. The hills are “believed to get its dark red color from tholins, complex molecules found across Pluto.”

Leave a comment

Mars’ seasonal dust storms

5:53 pm

Data from the many Martian orbiters since 1997 have allowed scientists to roughly outline a seasonal pattern of dust storms on Mars.

Most Martian dust storms are localized, smaller than about 1,200 miles (about 2,000 kilometers) across and dissipating within a few days. Some become regional, affecting up to a third of the planet and persisting up to three weeks. A few encircle Mars, covering the southern hemisphere but not the whole planet. Twice since 1997, global dust storms have fully enshrouded Mars. The behavior of large regional dust storms in Martian years that include global dust storms is currently unclear, and years with a global storm were not included in the new analysis.

They have also found three types of regional dust storms, all of which appear to occur each Martian year.

Leave a comment

Four new names proposed for periodic table

9:12 am

Scientists in Russia, Japan, and the United States have proposed four new names for the elements they helped discover.

The periodic table will soon have four new names added to its lower right-hand corner. Element 113 should be named nihonium (Nh); element 115 moscovium (Mv); element 117 tennessine (Tc) and element 118 oganesson (Og), according to proposals outlined on 8 June by chemistry’s governing body, the International Union of Pure and Applied Chemistry (IUPAC).

The laboratories who were credited with the discovery of the elements – in Russia, the United States and Japan – got to propose the names under the constraint that elements can only be named after one of their chemical or physical properties, a mythological concept, a mineral, a place or country, or a scientist.

The last choice, oganesson, is only the second element named after a living person. It will one of a more than a dozen elements named after individuals, overall.

The post originally said that ogranesson was only the second named after a person. My readers noted that many elements had been named for people, which implied the article was wrong. In truth, I was wrong. The article was more specific and correct, noting that this was only the second element to be named for a living person, as the editor of Nature wrote to explain. I have thus corrected the post, and noted my error here.

12 comments

National Science Foundation considers shuttering Arecibo

9:33 am

Faced with tight budgets, the National Science Foundation (NSF) is considering several options for the future operation of the Arecibo Observatory, the world’s largest single radio telescope dish, including its complete removal.

[T]he NSF could mothball the site, shutting it down in such a way that it could restart (sometime in the future). Or it could dismantle the telescope altogether and restore the area to its natural state, as required by law if the agency fully divests itself of the observatory and closes it. Previous studies have said such a process could cost around $100 million—more than a decade’s worth of its current funding for telescope operations. Jim Ulvestad, director of the NSF Division of Astronomical Sciences, says the agency is still investigating, not concluding. “No alternative has been selected at this juncture,” he says. And much consideration will go into the final financial decision, whatever it may be. Some outside the agency see writing on the wall. “NSF is dead serious about offloading Arecibo funding to someone else—anyone else,” says Ellen Howell, a former staff scientist at Arecibo and now a faculty member at the Lunar and Planetary Laboratory (LPL) in Tucson, Arizona.

The article spends a lot of time talking about how wonderful Arecibo is, but never tells us how many astronomers actually demand to use it. Is it oversubscribed, like Hubble, where five times the number of astronomers request time than can be handled, or does it often sit unused because not enough astronomers require its use? NSF and the government do not have unlimited funds, and need to focus their spending where the demand is. If Arecibo is not in demand, then they are wise to consider closing it, or handing it off to someone who wants it.

3 comments

LISA Pathfinder proves space-based gravity wave detection technology

8:43 am

Engineers have announced that the gravity wave detection technology being tested in orbit by Europe’s LISA Pathfinder works.

To show that the necessary sensitivity is possible, LISA Pathfinder measures the distance between two masses, both of which are inside the spacecraft. “We’ve shrunk the arm of a large gravitational wave antenna to 35 centimeters so we could show it works properly,” Paul McNamara, LISA Pathfinder project scientist, told the press conference.

LISA Pathfinder was launched in December 2015 to a spot 1.5 million kilometers from Earth. When its test masses where first released to float free in February, “the relief was unbelievable,” McNamara says. Science operations began on 1 March and on that first day the team was able to measure distance variations between the masses much smaller than LISA Pathfinder’s mission requirements, Stefano Vitale, the mission’s principle investigator, told reporters. After a month, the variations were even smaller, “very close to [eLISA] requirements,” he says.

They now hope to launch an array of at least three such spacecraft by the mid-2030s.

Leave a comment

Sunspot cycle update

9:56 am

NOAA today released its monthly update of the solar cycle, showing the Sun’s sunspot activity in May. It is annotated and posted below.

Mayl 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.

Though sunspot activity increased in May, the increase was not significant. The ramp down from solar maximum continues to track the 2007 low prediction for this maximum.

Meanwhile, the Sun continues its first multi-day string of blank days since 2011, now up to 3 days with all indications suggesting it will continue at least one more day. This early blank string, combined with the relatively fast decline in sunspots in the past two years, suggests that the solar maximum is ending sooner than predicted by the 2009 prediction (the red curve above), and that the next minimum will possibly be longer as well.

9 comments

Titan over Saturn’s rings

9:35 am

Titan over Saturn's rings

Cool image time! The picture on the right, taken on January 26, 2016 by Cassini and reduced and cropped to show here, captures Titan above Saturn’s rings, which are themselves partly obscured by the shadow of Saturn (unseen on the right) that falls across them.

Make sure you go to look at the full image. This is the kind of vista that artists in the 1950s imagined we’d see once we began to explore the solar system.

Leave a comment

No sunspots for the first time in two years

10:13 pm

For the first time since July 17, 2014, and only the second time since 2011 at the beginning of the solar maximum, the Sun was blank today, with no sunspots visible on its surface.

I expect the next monthly update of the solar cycle will arrive early next week, and though I expect it will show a slight increase during the past month, it will also show that the ramp down to solar minimum is continuing unabated.

Leave a comment

California moves to ban climate dissent

11:35 am

Climate fascists: The California legislature is considering a bill that would make it illegal to express skepticism about human-caused global warming.

The bill declares that there is no legitimate disagreement on the causes and extent of climate change, stating that, “There is broad scientific consensus that anthropogenic global warming is occurring and changing the world’s climate patterns, and that the primary cause is the emission of greenhouse gases from the production and combustion of fossil fuels, such as coal, oil, and natural gas.”

What I find frightening about this is that the liberal Democrats who are writing and pushing this bill, with the full support of numerous liberal environmentalist groups, no longer feel the slightest shame about their oppressive and tyrannical preferences. They are now out in the open, suggesting that they sense a wide support for their actions. I fear that they are right.

4 comments

Pluto: the world’s largest lava lamp

12:26 pm

In comparing the New Horizons’ data with computer simulations, scientists have determined that the frozen nitrogen in the heart-shaped Sputnik Planum region rises and sinks as the nitrogen is heated from below.

McKinnon and colleagues believe the pattern of these cells stems from the slow thermal convection of the nitrogen-dominated ices that fill Sputnik Planum. A reservoir that’s likely several miles deep in some places, the solid nitrogen is warmed by Pluto’s modest internal heat, becomes buoyant and rises up in great blobs – like a lava lamp – before cooling off and sinking again to renew the cycle. The computer models show that ice need only be a few miles deep for this process to occur, and that the convection cells are very broad. The models also show that these blobs of overturning solid nitrogen can slowly evolve and merge over millions of years. Ridges that mark where cooled nitrogen ice sinks back down can be pinched off and abandoned, resulting in Y- or X-shaped features in junctions where three or four convection cells once met.

One comment
1 … 156 157 158 159 160 … 279