Tag: science

The layered mesas of Mars

12:06 pm

The mesas of Uzboi Valles

Cool image time! The image above, reduced and cropped to post here, shows the layered deposits and complex erosion that has taken place in this area of Mars dubbed Uzboi Vallis. As noted at the Mars Reconnaissance Orbiter post,

Layered deposits in Uzboi Vallis sometimes occur in alcoves along the valley and/or below where tributaries enter it. These deposits may record deposition into a large lake that once filled Uzboi Vallis when it was temporarily dammed at its northern end by the rim of Holden Crater and before it was overtopped and breached allowing water to drain back out of the valley.

It is important when looking at these erosion patterns, including the strangely shaped rippled sand dunes scattered through the larger image, that wind possibly plays an even more important part in causing erosion on Mars than liquid water might have in the far past.

Either way, the terrain here has the same stark and fascinating beauty as that seen in the American southwest. If we can ever make it possible to live on Mars, this will definitely be a place to visit when on vacation.

6 comments

Trump budget proposal

11:24 am

The Trump administration today released its overall rough budget plan for 2018. This is not a detailed budget, but an summary of their plan, indicating where they wish to cut and where they wish to increase budgets. The proposal is also not complete, making no mention of the administration’s budget plans for many departments, such as the National Science Foundation.

Science research in the federal government is significantly impacted, but not as badly as most of the articles you will read in the mainstream anti-Trump, Democratic Party press. A few examples:

I must note that not all the news stories are blindly hostile to this budget proposal:

Of all the science agencies, NASA probably came off with the least change. The budget cuts only about 5% from the agency’s Earth science budget, while cutting some specific Earth science missions. The budget also supports SLS/Orion, though it finally puts the nail in the coffin of the asteroid redirect mission, an Obama proposal that has never garnered any interest from anyone else.

The Trump budget proposal in context

The key to understanding all these budget cuts is to see them in context, to compare the 2018 proposed budgets with the budgets these agencies received in the past. The table on the right gives some of this context (numbers shown are in millions) for several of the science agencies most effected by the proposal. The proposal is not detailed enough to pin down the changes for many other science agencies, but from this table it is clear that the Trump administration is not calling for the end of science, and is proposing some reasonable cost cutting, something that has been rare in government for many years.

What will be missed by most of the press about this Trump budget proposal is that it is not trying to trim the size of the federal government. While it cuts spending in many departments, those cuts are entirely aimed at providing room to raise the budget of the Defense Department by $54 billion. While I can applaud the desire of the Trump administration to be revenue neutral, the stark fact remains that by remaining revenue neutral Trump still leaves us with a gigantic annual federal deficit. They have made no effort to balance the overall budget.

Worse, this proposal would repeal the Budget Control Act of 2011, which imposed sequestration to the federal budget and has actually done the most in the past half century to bring that budget under control. Once this act is repealed, it will allow the spenders in Congress (of which the Republicans are as guilty as the Democrats) to open the floodgates once again. This will not be good.

Let me add one good aspect of the Trump budget. It proposes to eliminate a whole range of government political agencies that accomplish nothing but provide pork or to propagandize the Democratic Party’s positions:

The Budget also proposes to eliminate funding for other independent agencies, including: the African Development Foundation; the Appalachian Regional Commission; the Chemical Safety Board; the Corporation for National and Community Service; the Corporation for Public Broadcasting; the Delta Regional Authority; the Denali Commission; the Institute of Museum and Library Services; the Inter-American Foundation; the U.S. Trade and Development Agency; the Legal Services Corporation; the National Endowment for the Arts; the National Endowment for the Humanities; the Neighborhood Reinvestment Corporation; the Northern Border Regional Commission; the Overseas Private Investment Corporation; the United States Institute of Peace; the United States Interagency Council on Homelessness; and the Woodrow Wilson International Center for Scholars.

Getting these eliminated will at least be a start to cleaning up the mess in Washington.

48 comments

Want to watch a nuclear bomb go off? You can!

9:49 am

Engineers at Lawrence Livermore National Laboratory (LLNL) have obtained declassified films of many of the nuclear tests performed by the U.S. from 1945 to 1962 and are digitally scanning them and preserving them for posterity.

Conducted by LLNL weapon physicist Greg Spriggs and a team of film experts, archivists, and software developers, the project’s goal was to track down as many as possible of the ten-thousand 2,400 frames per second reels of film. This was because the cine film, and its immense historical and scientific value, was in danger of being lost for all time. The reels were mostly of acetate stock that was not stored under anything like ideal conditions and was slowly decaying or being attacked by fungus and microbes.

“You can smell vinegar when you open the cans, which is one of the byproducts of the decomposition process of these films,” says Spriggs. “We know that these films are on the brink of decomposing to the point where they’ll become useless. The data that we’re collecting now must be preserved in a digital form because no matter how well you treat the films, no matter how well you preserve or store them, they will decompose. They’re made out of organic material, and organic material decomposes. So this is it. We got to this project just in time to save the data.”

You can view a number of the films at the second link above. I have embedded below the fold just one, from Operation Teapot in 1955. This was a series of 14 tests in Nevada. In this particular video the explosion occurs in the air, and you can sense the incredible force of the explosion when the shock wave hits the ground and bounces back, producing the mushroom cloud. Not much would have survived that impact.
» Read more

18 comments

Less evidence of dark matter in early universe

10:49 pm

The uncertainty of science: Astronomers have discovered less evidence of dark matter surrounding galaxies in early universe.

Stars in the outer regions of some far-off galaxies move more slowly than stars closer to the center, indicating a lack of dark matter, astronomer Reinhard Genzel and colleagues report online March 15 in Nature. If confirmed, the result could lead astronomers to reconsider the role dark matter played in early galaxy evolution and might also offer clues to how nearby elliptical galaxies evolved.

In contrast with these distant galaxies, stars orbiting on the outskirts of the Milky Way and other nearby galaxies move too fast for their velocities to result only from the gravity of gas and stars closer to the galactic center. If visible galactic matter is embedded in a cloud of invisible dark matter, though, gravity from the invisible matter can explain the high stellar velocities. Using stars’ orbital velocities in nearby galaxies as a reference, astronomers expected that stars in galaxies farther away would behave similarly. “Turns out that is not the case,” says study coauthor Stijn Wuyts of the University of Bath in England.

In other words, scientists at this moment really have no idea what causes the faster rotation in the outskirts of modern nearby galaxies.

17 comments

Titan’s fizzy oceans?

11:36 am

New research suggests that the hydrocarbon lakes of Titan might periodically fizz with nitrogen bubbles.

A recent NASA-funded study has shown how the hydrocarbon lakes and seas of Saturn’s moon Titan might occasionally erupt with dramatic patches of bubbles.

For the study, researchers at NASA’s Jet Propulsion Laboratory in Pasadena, California, simulated the frigid surface conditions on Titan, finding that significant amounts of nitrogen can be dissolved in the extremely cold liquid methane that rains from the skies and collects in rivers, lakes and seas. They demonstrated that slight changes in temperature, air pressure or composition can cause the nitrogen to rapidly separate out of solution, like the fizz that results when opening a bottle of carbonated soda.

These results might help explain the mysterious islands that seem to appear and disappear and then reappear in Titan’s lakes. Rather than islands, they might be patches of nitrogen bubbles.

2 comments

Saturn’s weird moon Pan

9:34 am

Pan

New images from Cassini have provided scientists their first sharp images of Saturn’s moon Pan, and what those images show is something really weird. The image on the right is only one sample, with the link providing more.

Pan orbits in a gap between two rings, and the ridge might have accumulated from material from those rings. Then again, maybe not. It will take more data to I think completely unravel how this moon got to look like it does.

12 comments

At the crest

12:15 pm

Looking north at the crest

Cool images time! The image above, cropped and reduced to show here, is a panorama that I have created from the most recent images sent down from Opportunity yesterday. The rover sits on the crest of the rim of Endeavour Crater, and this panorama looks north at that crest, back in the direction where the rover has come. The rovers tracks can be seen fading away into the distance slightly to the left of the crestline..If you click on the picture you can see the full resolution image.

The crater floor is to the right, the plains that surround the crater are to the left.

Below is another panorama, created by me from the same images sent down today, this time looking south at the crest in the direction Opportunity is heading. Once again, if you click on the picture you can see the full resolution version.

The full set of today’s images from Opportunity suggest that the science team took them to assemble a full 360 degree panorama before they begin the journey south to the gully that is just now becoming visible at the southernmost edge of the most recent overhead traverse image. To get to that gully they will now have to descend off the crest and down outside the rim of Endeavour Crater, moving to the right in the panorama below. This is therefore their last opportunity for awhile to get a good view from a high overlook.

Looking south at the crest

2 comments

Sunspot update for February 2017

10:04 am

On Sunday NOAA posted its monthly update of the solar cycle, covering sunspot activity for February. As I have been doing every month since 2010, I am posting it here with annotations to give it context.

February 2017 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.

The decline in sunspots continues. Though the increase in activity from January held in February, the overall activity remains significantly below the predictions, and continues to point to a much earlier arrival of the solar minimum, sometime in 2019.

0 comments

Scientists estimate age of bright spots in Occator Crater on Ceres

8:22 am

Using crater counts and a careful analysis of features in Occator Crater on Ceres, scientists have estimated that the last major eruption occurred about 4 million years ago.

Nathues and his team interpret the central pit with its rocky, jagged ridge as a remnant of a former central mountain. It formed as a result of the impact that created Occator Crater some 34 million years ago and collapsed later. The dome of bright material is much younger: only approximately four million years. The key to determining these ages was the accurate counting and measuring of smaller craters torn by later impacts. This method’s basic assumption is that surfaces showing many craters are older than those that are less strongly “perforated”. Since even very small craters are visible in highly resolved images, the new study contains the most accurate dating so far.

“The age and appearance of the material surrounding the bright dome indicate that Cerealia Facula was formed by a recurring, eruptive process, which also hurled material into more outward regions of the central pit”, says Nathues. “A single eruptive event is rather unlikely,” he adds. A look into the Jupiter system supports this theory. The moons Callisto and Ganymede show similar domes. Researchers interpret them as volcanic deposits and thus as signs of cryovolcanism.

The volcano itself has slumped away, leaving behind the bright depression. Whether any cryovolcanism is still occurring underground remains unknown.

0 comments

Cuts to NOAA, EPA, and the environmental bureaucracy

8:57 am

Two articles today outline some of the proposed cuts the Trump administration is considering for the EPA and NOAA and their generally bloated and politicized administrative bureaucracies.

The first article focuses on the proposed cuts to the EPA, which would reduce the overall budget to that agency by about 25%.

The Trump administration wants to cut spending by EPA’s Office of Research and Development (ORD) by more than 40% from roughly $510 million to $290 million, according to sources that have seen preliminary directives from the White House’s Office of Management and Budget (OMB). The cuts target scientific work in fields including climate change, air and water quality, and chemical safety. EPA’s $50 million external grant program for environmental scientists at universities would disappear altogether. Such erasures represent just part of a larger plan to shrink EPA’s budget by 25% to $6.1 billion, and cut its workforce by 20% to 12,400 employees, in the 2018 fiscal year that begins 1 October.

The second article focuses on proposed cuts aimed at NOAA and within the Commerce Department, with cuts in specific departments ranging from 5% to 26%, with an overall cut to NOAA of 17%.
» Read more

6 comments

A propeller in Saturn’s A ring

3:45 pm

A propeller in Saturn's A ring

Cool image time! The image on the right, cropped and reduced to show here, captures the same propeller feature in Saturn’s A ring, with the top image showing the sunlight side and the bottom image the side away from the Sun.

Cassini scientists have been tracking the orbit of this object for the past decade, tracing the effect that the ring has upon it. Now, as Cassini has moved in close to the ring as part of its ring-grazing orbits, it was able to obtain this extreme close-up view of the propeller, enabling researchers to examine its effects on the ring. These views, and others like them, will inform models and studies in new ways going forward.

…The propeller’s central moonlet would only be a couple of pixels across in these images, and may not actually be resolved here. The lit-side image shows that a bright, narrow band of material connects the moonlet directly to the larger ring, in agreement with dynamical models. That same thin band of material may also be obscuring the moonlet from view.

Lengthwise along the propeller is a gap in the ring that the moonlet has pried open. The gap appears dark on both the lit and unlit sides. Flanking the gap near the moonlet are regions of enhanced density, which appear bright on the lit side and more mottled on the unlit side.

The scale of the two images is slightly different, 0.33 and 0.44 miles, as they were taken as Cassini was zipping past during one of its ring-grazing orbits on February 21.

To my eye, the effect here faintly resembles a wake produced by a boat in water, except that the wake moves in opposite directions on opposite sides of the tiny moonlet as it plows through the A ring.

0 comments

Two of five cameras on Japan’s Venus orbiter Akatsuki shut down

12:08 pm

Japan has been forced to shut down operation on two of the five cameras on its Venus orbiter Akatsuki.

They think the problem has been caused by the additional five years required to get into Venus orbit when its main engine failed to fire during the first orbital attempt in 2010. During those five years the spacecraft was exposed to more radiation that expected, possibly damaging its equipment.

0 comments

Asteroid breaks in two, each piece develops a tail

2:08 pm

Astronomers have discovered a main belt asteroid that six years ago broke in two, after which both pieces developed tails resembling comets.

“The results derived from the evolution of the orbit show that the asteroid fragmented approximately six years ago, which makes it the youngest known asteroid pair in the Solar System to date,” says Fernando Moreno, researcher at the Institute of Astrophysics of Andalusia (IAA-CSIC), in charge of the project.

P/2016 J1 presents another important peculiarity, which makes it very unusual. “Both fragments are activated, i.e., they display dust structures similar to comets. This is the first time we observe an asteroid pair with simultaneous activity,” says Fernando Moreno (IAA-CSIC).

Analyses revealed that the asteroids were activated near their perihelion – the point on the orbit nearest to de Sun – between the end of 2015 and the beginning of 2016, and that they remained for a period of between six and nine months. The span of time between the moment of fragmentation and their bout of activity implies that the two events are not related. In fact, the data suggests that the fragmentation also happened near the perihelion but during the previous orbit (it takes P/2016 J1 5.65 years to spin around the Sun). “In all likelihood, the dust emission is due to the sublimation of ice that was left exposed after the fragmentation,” says Moreno (IAA-CSIC).

I suspect that the more we learn about asteroids and comets the more we will blur the line that separates them.

1 comment

The winds of Mars

10:00 am

New data from Curiosity has confirmed that the winds of Mars have been the primary force shaping the red planet’s landscape for billions of years.

The new data suggests that Mount Sharp once filled Gale Crater, and it was the winds that eroded it away to create the impression that it is the crater’s central peak. Instead it appears that it is the crater’s original floor!

Below the fold is the video from the link showing a number of dust devils imaged by Curiosity.

This link provides a gif animation showing the surprisingly significant changes to the ripples in the sand dunes directly below Curiosity that take place in only one day. The changes are astonishing, and show that even though Mars’ atmosphere is far thinner than Earth’s, it is capable of moving things quickly across the Martian surface.
» Read more

0 comments

The oldest fossils ever?

7:35 pm

Scientists think they have found the oldest fossils ever in Canada.

Scientists say they have found the world’s oldest fossils, thought to have formed between 3.77bn and 4.28bn years ago. Comprised of tiny tubes and filaments made of an iron oxide known as haematite, the microfossils are believed to be the remains of bacteria that once thrived underwater around hydrothermal vents, relying on chemical reactions involving iron for their energy.

If correct, these fossils offer the oldest direct evidence for life on the planet. And that, the study’s authors say, offers insights into the origins of life on Earth. “If these rocks do indeed turn out to be 4.28 [bn years old] then we are talking about the origins of life developing very soon after the oceans formed 4.4bn years ago,” said Matthew Dodd, the first author of the research from University College, London.

This discovery reminds me of the Mars fossils discovered in the late 1990s. There were enormous uncertainties with that discovery, all of which eventually caused most scientists in the field to reject the result. The same thing could be the case here.

Still in Dallas. I hope to get caught up tomorrow.

14 comments

China considering multi-asteroid mission

7:16 pm

The competition heats up: China is considering an unmanned probe to visit three different asteroids, including Apophis.

According to details that have previously emerged, one proposal is for a launch via Long March 3B rocket to take place in early 2022, with rendezvous with Apophis a year later and spend 220 days in orbit.

Then the probe would depart Apophis for a flyby of 2002 EX11 in 2025, and finally landing on 1996 FG3 in 2027, where it would, in Ji’s words, “conduct in-situ sampling analysis on the surface”.

The proposal is only in the design stage, but it should definitely be taken seriously. China is committing more and more of its resources to its space program, as that program is giving that government a big payoff in international recognition.

Posted in the airport in Dallas, where I have to wait an extra three hours because American Airlines practically shut the door to my connecting flight in my face. Their flight from Belize was late, and then Customs and the TSA conspired to create giant lines for no reason. Even though I had a friend at the gate with whom we were in contact by text who could tell them I was only a minute away, they shut the door anyway.

I have avoided American for more than a decade because they did something as obnoxious to me before. I think it might be a decade before I fly them again.

2 comments

A solar system of exoEarths!

1:53 pm

Astronomers have discovered a nearby solar system of exoplanets, all approximately Earth-sized with at least three in the habitable.

Following these initial findings, the star was systematically monitored to find out whether it contained any other planets. The result of this follow-up exceeded all expectations: TRAPPIST-1 has at least seven planets, all of which are Earth-sized (to within 15%). The six nearest planets (b to g) orbit their star in 1.5 to 12 days (the period of the seventh planet remains to be determined), and are 20 to 90 times closer to their star than the distance from the Earth to the Sun. At such distances, the tidal forces exerted by the star are considerable, locking the planets into synchronous rotation, which means that they rotate about their axis exactly once in one orbit, thus always showing the same face to their star (just as the Moon does relative to the Earth).

The planets of TRAPPIST-1 have insolations, and therefore average temperatures, similar to Earth’s: the insolation of the innermost planet (b) is slightly higher than that of Mercury, while the outermost planets (g and h) have an insolation that is a little lower than that of Mars. The insolations of at least three of the planets (e, f and g) are compatible with the existence of liquid water on their surface for a wide range of atmospheric compositions, as is shown by numerical simulations of their climate. Due to their synchronous rotation, it cannot be excluded that the planets with the highest irradiation (b, c and d) may harbor liquid water in temperate regions with little or no sunlight.

More here. The star, a cool dwarf, is only 40 light years away.

Posted in the Belize City airport, as we wait for our pickup.

8 comments

Scientists propose new planet definition that reinstates Pluto

6:03 pm

Unhappy since 2006 with the definition of “planet” imposed by the International Astronomical Union (IAU) that demoted Pluto, planetary scientists, including New Horizons principal investigator Alan Stern, have now proposed a new definition that they think is more appropriate and would reinstate Pluto.

The scientists suggest planets should constitute as “round objects in space that are smaller than stars,” thus excluding white dwarfs, neutron stars, and black holes from the planetary status. “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,” the proposal elaborates, noting that the Earth’s moon would constitute as a planet under the new definition.

Stern and his colleagues note that the IAU’s definition of a planet is too narrow and recognizes planets only as objects that orbit our sun and “requires zone clearing, which no planet in our solar system can satisfy since new small bodies are constantly injected into planet-crossing orbits.”

Make sense to me as well as a lot of people. The definition created in 2006 was never very satisfactory, and I know many planetary scientists who have never accepted it.

11 comments
1 … 238 239 240 241 242 … 439