Feed aggregator

Dunes carving up rock (3D)

Cosmic Diary by Lori Fenton - January 16, 2017


A Piece of Mars: Get out your 3D blue/red glasses (or look here for a 2D version if you can’t find them). This is a 3.2×1.8 km (2×1.13 mi) scene showing dark dunes carving lanes 50-70 m (165-230 ft) deep into a stack of brighter sedimentary layers. Over time, the sand wears down the rock into yardangs, the elongated remnants of rock the sand didn’t manage to reach. Here we see the process ongoing; perhaps in a few million years there will be nothing left but a few streamlined peaks. Those murdering basterds [sic]. (HiRISE ESP_034419_2015, NASA/JPL/Univ. of Arizona)

Tortoise and hare

Cosmic Diary by Lori Fenton - January 12, 2017


A Piece of Mars: There’s a lot of evidence for both fast and slow movement in this 480×270 m (0.3×0.17 mi) scene.

The tortoise: The rippled surface at the top is high ground: the top of a dune. Wind pushes the ripples toward a steep sunlit slope, creating long thin, dark avalanches that slowly inch the slipface forward. At the bottom of the slope, which is shielded from winds blowing from the top, ripples have been formed by wind blowing from the left.

The hare: Oblivious to both the slow progression of ripples and dunes, 5-25 m wide dust devils have blazed on by, leaving behind erratic trails.

(HiRISE ESP_048592_2070, NASA/JPL/Univ. of Arizona)

Crater ejecta on old ripples

Cosmic Diary by Lori Fenton - January 03, 2017


A Piece of Mars: Mars rarely does anything without drama. Long ago in this 0.96×0.54 km (0.6×0.34 mi) scene, large ripples formed and then, presumably, lithified (turned into rock). Some time after that, an impact formed the crater in the center, throwing debris into an ejecta blanket that covered the lithified ripples. That ejecta blanket sat around long enough to acquire some smaller impact craters of its own. Since then, most of that ejecta blanket has eroded away, exposing the ripples to view once again. (HiRISE ESP_011699_1910, NASA/JPL/Univ. of Arizona)

Steno’s principles, or “how to make sense of pretty landscapes”

Cosmic Diary by Lori Fenton - December 26, 2016


A Piece of Mars: Nicholas Steno was a 19th century geologist, who came up with some principles that are still used today to guide interpretation of exposed sedimentary rocks. The principles seem a bit obvious, but then some of the most profound principles can be like that. Emily Lakdawalla of the Planetary Society describes them in more detail here, with really good examples. You can use these principles to do forensics on a landscape, to see what happened and when.

You can see all three principles at work in this image.

#1: Stuff makes horizontal layers. (This isn’t always true, e.g., dunes and deltas make tilted layers, but most sediments pile up into flat, horizontal layers.) You can see that at work here: A thick layer of dark gray stuff once piled up on a flat surface of brighter stuff. Some of the dark gray stuff has since eroded away, but you can see that both the gray and the brighter stuff originally piled up in flat-lying layers.

#2: Older stuff is at the bottom. (Because newer stuff buries the older stuff, like the papers on my desk and the veggies in my fridge.) In this image, the brighter stuff must be older than the darker gray stuff, because the bright stuff is on the bottom.

#3: You can’t see the layers until they’re exposed by erosion or tectonics. (Because they’re buried. So if you see layers, you know something has happened so you can see them.) You can see the edges of the dark gray stuff, so you know it’s been partially eroded away – otherwise you’d never know the underlying bright stuff was ever there. Some of the material from the dark gray layer has been reformed into dark bedforms on the brighter layer, and those bedforms are probably the youngest features in this scene.

What I like most about this image has to do with yet another principle of layered stuff: Things that cut across other things are younger. Things that have been cut across are older (Like if you chop down a tree, then the axe cuts on the tree trunk must have been made after the tree itself grew. Duh, right?). You can see that in this image: on top of the dark gray layer are some old bedforms. They must be quite old, even cemented or lithified (turned into rock that the wind can’t easily move), because they’ve been cut by erosion at the edge of the gray layer. So not only was the gray layer once more extensive, but it had ripples on it, and those ripples formed and became immobile before that erosion ever happened.

(HiRISE ESP_030460_1525, NASA/JPL/Univ. of Arizona)

The trail of a dune

Cosmic Diary by Lori Fenton - December 19, 2016


A Piece of Mars: A low, broad dune occupies the center of this 800×450 m (0.5×0.28 mi) scene, blown by a dominant wind towards the lower left. The slip face on the lee side has several small avalanches, formed as the slope oversteepens (this is how dunes crawl along the surface). Upwind, among other fainter lines, is a prominent bright line: it is a former slip face of this dune, possibly formed from a thick accumulation of bright dust (maybe there was a big dust storm that year). Farther upwind, another dune slowly approaches. (HiRISE ESP_033955_2065, NASA/JPL/Univ. of Arizona)

Them that make ripples and them that don’t

Cosmic Diary by Lori Fenton - December 12, 2016


A Piece of Mars: Higher ground is to the left. You’re seeing a tan layer sandwiched between two gray layers in this 0.96×0.54 km (0.6×0.34 mi) scene. Large ripples have accumulated in the lowest area to the right, which is the floor of an old river channel. Ripples have also formed on the gray upper layer. But not the middle tan layer – maybe it’s too fine-grained to erode into sand grains, or maybe it erodes too slowly to allow any eroded sand grains to pile into ripples before they’re blown away. (HiRISE ESP_048196_1995, NASA/JPL/Univ. of Arizona)

Martian spiders

Cosmic Diary by Lori Fenton - December 05, 2016


A Piece of Mars: Martian spiders, or araneiforms, are geological structures found at high latitudes on Mars. The dark splotch with branching arms in this 0.48×0.27 km (0.3×0.17 mi) scene is a good example. They form in the springtime, when bright frost still covers a darker sandy soil, but some sunlight filters through the frost to warm the underlying surface. Sublimation of gas (under the frost but just above the soil) creates enough pressure that little explosions occur like dry geysers, punching through the frost and blowing up sand that then falls back to the surface as a dark splotch. If the wind is blowing when this happens, then the dark splotch is carried a ways downwind, but that hasn’t happened in this case. (HiRISE ESP_048189_0985, NASA/JPL/Univ. of Arizona)

Grainfall

Cosmic Diary by Lori Fenton - November 28, 2016


A Piece of Mars: The dunes climbing over a rocky surface in this 0.96×0.54 km (0.6×0.34 mi) scene are mostly yellow because they’re covered (and therefore kept immobile) by dust. The crest of one dune, though, shows recent activity: dark sand has been pushed by the wind up the lower right side, and then shot (cannonball-style) over the brink, where it slowly piles up on the upper left side. This pileup is called grainfall, because that’s what the sand grains have done here (rather than sliding downhill, avalanche-style, which is called grainflow). There’s a dune on the left side of the image that hasn’t experienced this activity, maybe because it’s a little more sheltered from the wind. (HiRISE ESP_047779_1655, NASA/JPL/Univ. of Arizona)

Bedforms on crater rims

Cosmic Diary by Lori Fenton - November 21, 2016


A Piece of Mars: Dunes and ripples most commonly form in topographic lows. But not in this 0.96×0.54 km (0.6×0.34 mi) scene. Here, and in other places on Mars, these bedforms (called TARs) form on plains, and sometimes appear to cling to the rims of craters – which are topographic highs, not lows. It’s not clear how this happens: Does the topography of the crater rim provide a wind shadow that allows windblown sediment to accumulate there? Or was there simply more loose material on the crater rims to begin with, allowing these things to form in place? I’m open to suggestions. (HiRISE ESP_047787_1910 NASA/JPL/Univ. of Arizona)

Shadows behind boulders

Cosmic Diary by Lori Fenton - November 14, 2016


A Piece of Mars: Bright material (either dust or sand) has accumulated in the lee of wagon- to car-sized boulders in this 0.96×0.54 km (0.6×0.34 mi) scene. It’s perhaps something like the Rocknest sand shadow that Curiosity visited a few years back. The wind blows from lower right to upper left, carrying along sediment that occasionally gets trapped in the protected areas behind the boulders. These sand shadows aren’t very thick, as the underlying texture (polygonal terrain!) is visible through them. (HiRISE ESP_047798_1150, NASA/JPL/Univ. of Arizona)

Dunes and rock hurdles in Gale crater (3D)

Cosmic Diary by Lori Fenton - November 07, 2016


A Piece of Mars: Wind from the upper left is blowing dark dunes toward the lower right in this 1.92×1.08 km (1.19×0.67 mi) anaglyph (if you don’t have your red/blue 3D glasses handy, you can also check out the black and white 2D version). The dunes are crossing through hurdles aligned to make their progress as difficult as possible, but the dunes nevertheless are slowly making their way through. Ironically, the bright “hurdles” are themselves lithified dunes that are perhaps billions of years old. (HiRISE ESP_020555_1755/ESP_047139_1755 NASA/JPL/Univ. of Arizona)

On Mars the wind carves stream channels

Cosmic Diary by Lori Fenton - October 31, 2016


A Piece of Mars: This 1.6×2 km (1×1.24 mi) scene mostly shows what wind will do to fine-grained, weakly-consolidated surfaces. It has created topography that further strengthens wind scour in the hollows, which even leave kilometers-long grooves reminiscent of water-carved streams. If this were Earth I’d guess they had been carved by water first. But this is Mars, where the wind is in charge. (HiRISE ESP_046504_1785, NASA/JPL/Univ. of Arizona)

The spire in Eberswalde crater

Cosmic Diary by Lori Fenton - October 10, 2016


A Piece of Mars: OK, you have to bring out the red/blue glasses for this one. (Or click here if you’re missing your glasses and want the black and white version.) Eberswalde crater has some lovely layered deposits, long ago laid down by running water, and since eroded steadily by the wind. The wind leaves behind the most resistant parts (mainly fluvial channels that were more cemented). The center of this image shows a tall spire: the tallest of the flat layers (top of the “wedding cake”) is 290 m (950 ft) across and casts a shadow indicating it’s 200 m (656 ft) above the next layer down. That central spike is another 70 m (230 ft) taller yet, by itself nearly rivaling the “Totem Pole” in Monument Valley. Check out the rest of the red/blue anaglyph, it’s stunning. (HiRISE, ESP_047185_1560/ESP_047119_1560, NASA/JPL/Univ. of Arizona)

Windblown: ancient and recent

Cosmic Diary by Lori Fenton - October 03, 2016


A Piece of Mars: HiRISE is celebrating 10 years of success by showcasing its first high resolution image, taken back in 2006. Here is a portion of it, shown at 1/4 the full resolution (the scene is 2.5×2.5 km across). I highly recommend downloading the HiRISE image viewer and looking at the whole thing, it’s an amazing landscape. The portion shown here has many different ripple-like features, formed by a wind blowing from left to right. Notice that those in the middle and middle-left are a bit fainter: these are ripple-like features that were carved into the bedrock by the wind, and they may be much older than the sharper-edged ones nearby. (HiRISE TRA_000823_1720, NASA/JPL/Univ. of Arizona)

What the Hack

ENCORE  A computer virus that bombards you with pop-up ads is one thing. A computer virus that shuts down a city’s electric grid is another. Welcome to the new generation of cybercrime. Discover what it will take to protect our power, communication and transportation systems as scientists try to stay ahead of hackers in an ever-escalating game of cat and mouse.

The expert who helped decipher the centrifuge-destroying Stuxnet virus tells us what he thinks is next. Also convenience vs. vulnerability as we connect to the Internet of Everything. And, the journalist who wrote that Google was “making us stupid,” says automation is extracting an even higher toll: we’re losing basic skills. Such as how to fly airplanes.

Guests:

•   Ray Sims – Computer Technician, Computer Courage, Berkeley, California

•   Eric Chien – Technical Director of Security Technology and Response, Symantec

•   Paul Jacobs – Chairman and CEO of Qualcomm

•   Shankar Sastry – Dean of the College of Engineering, University of California, Berkeley, director of TRUST

v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} 0 0 1 255 1455 SETI Institute 12 3 1707 14.0 Normal 0 false false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;}

•   Nicholas Carr – Author of The Shallows: What the Internet Is Doing to Our Brains and the forthcoming “The Glass Cage”. His article, “The Great Forgetting,” is in the November 2013 issue of The Atlantic.

 

First released November 11, 2013.

Skeptic Check: Evolutionary Arms Race

ENCORE It’s hard to imagine the twists and turns of evolution that gave rise to Homo Sapiens. After all, it required geologic time, and the existence of many long-gone species that were once close relatives. That may be one reason why – according to a recent poll – one-third of all Americans reject the theory of evolution. They prefer to believe that humans and other living organisms have existed in their current form since the beginning of time.

v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} 0 0 1 348 1985 SETI Institute 16 4 2329 14.0

 

Normal 0 false false false false EN-US JA X-NONE

 

/* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;}

 

But if you’ve ever been sick, you’ve been the victim of evolution on a very observable time scale. Nasty viruses and bacteria take full advantage of evolutionary forces to adapt to new hosts. And they can do it quickly.

Discover how comparing the deadly 1918 flu virus with variants today may help us prevent the next pandemic. Also, while antibiotic resistance is threatening to become a major health crisis, better understanding of how bacteria evolve their defenses against our drugs may help us out.

And the geneticist who sequenced the Neanderthal genome says yes, our hirsute neighbors co-mingled with humans.

It’s Skeptic Check … but don’t take our word for it!

Guests:

•   Svante Pääbo – Evolutionary geneticist, Max Planck Institute for Evolutionary Anthropology, author of Neanderthal Man: In Search of Lost Genomes

•   Ann Reid – – Molecular biologist, executive director of the National Center for Science Education, Oakland, California

•   Martin Blaser – Microbiologist, New York University School of Medicine, member of the National Academy of Sciences, author of Missing Microbes: How the Overuse of Antibiotics Is Fueling Our Modern Plagues

•   Gautam Dantas – Pathologist, immunologist, Center for Genome Sciences and Systems Biology, Washington University, Saint Louis

First released March 31, 2014.

It's All Relative

A century ago, Albert Einstein rewrote our understanding of physics with his Theory of General Relativity. Our intuitive ideas about space, time, mass, and gravity turned out to be wrong.

Find out how this masterwork changed our understanding of how the universe works and why you can thank Einstein whenever you turn on your GPS.

Also, high-profile experiments looking for gravitational waves and for black holes will put the theories of the German genius to the test – will they pass?

And why the story of a box, a Geiger counter, and a zombie cat made Einstein and his friend Erwin Schrödinger uneasy about the quantum physics revolution.

Guests:

•   Jeffrey Bennett – Astronomer, author of What Is Relativity?: An Intuitive Introduction to Einstein’s Ideas, and Why They Matter

•   Beverly Berger – Theoretical physicist and the Secretary for the International Society on General Relativity and Gravitation

•   Hiawatha Bray – Technology reporter, Boston Globe, author of You Are Here: From the Compass to GPS, the History and Future of How We Find Ourselves

v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} 0 0 1 298 1705 SETI Institute 14 3 2000 14.0 Normal 0 false false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;}

•  Paul Halpern – Physicist at the University of the Sciences in Philadelphia, author of Einstein’s Dice and Schrödinger’s Cat: How Two Great Minds Battled Quantum Randomness to Create a Unified Theory of Physics

And To Space We Return

Earth may be the cradle of life, but our bodies are filled with materials cooked up billions of years ago in the scorching centers of stars. As Carl Sagan said, “We are all stardust.” We came from space, and some say it is to space we will return.

Discover an astronomer’s quest to track down remains of these ancient chemical kitchens. Plus, a scientist who says that it’s in our DNA to explore – and not just the nearby worlds of the solar system, but perhaps far beyond.

But would be still be human when we arrive? Hear what biological and cultural changes we might undergo in a multi-generational interstellar voyage.

Guests:

 •   Timothy Beers – Astronomer, University of Notre Dame

•   Chris Impey – Astronomer, University of Arizona, author of Beyond: Our Future in Space

v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} 0 0 1 181 1034 SETI Institute 8 2 1213 14.0 Normal 0 false false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;}

•   Cameron Smith – Archaeologist, Portland State University

Math's Days Are Numbered

ENCORE  Imagine a world without algebra. We can hear the sound of school children applauding. What practical use are parametric equations and polynomials, anyway? Even some scholars argue that algebra is the Latin of today, and should be dropped from the mandatory curriculum.

But why stop there? Maybe we should do away with math classes altogether.

An astronomer says he’d be out of work: we can all forget about understanding the origins of the universe, the cycles of the moon and how to communicate with alien life. Also, no math = no cybersecurity + hackers (who have taken math) will have the upper hand.

Also, without mathematics, you’ll laugh < you do now. The Simpsons creator Matt Groening has peppered his animated show with hidden math jokes.

And why mathematics = love.

Guests:

•   Andrew Hacker – Professor of political science and mathematics at Queens College, City University of New York. His article, “Is Algebra Necessary?”, appeared in The New York Times in 2012.

•   Bob Berman – Astronomy editor of The Old Farmer’s Almanac, the author of The Sun’s Heartbeat: And Other Stories from the Life of the Star That Powers Our Planet , and columnist for Astronomy Magazine. His article, “How Math Drives the Universe” is the cover story in the December 2013 issue.

•   Simon Singh – Science writer, author of The Simpsons and Their Mathematical Secrets

•   Rob ManningFlight system chief engineer at the Jet Propulsion Lab, responsible for NASA’s Curiosity rover

v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} 0 0 1 408 2329 SETI Institute 19 5 2732 14.0 Normal 0 false false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;}

•   Edward Frenkel – Professor of mathematics at the University of California, Berkeley, author of Love and Math: The Heart of Hidden Reality . His article, “The Perils of Hacking Math,” is found on the online magazine, Slate.

 

First released December 2, 2015.

Skeptic Check: After the Hereafter

There are few enduring truths, but one is that no one gets out of life alive. What’s less certain is what comes next. Does everything stop with death, or are we transported to another plane of existence? First-hand accounts of people who claim to have visited heaven are offered as proof of an afterlife. Now the author of one bestseller admits that his story was fabricated.

We’ll look at the genre of “heaven tourism” to see if it has anything to say about the possible existence of the hereafter, and why the idea of an afterlife seriously influences how we live our lives on Earth.

Also, a neurologist describes what is going on in the brain during near-death and other out-of-body experiences.

It’s Skeptic Check, our monthly look at critical thinking … but don’t take our word for it!

Guests:

•   Ben Radford – Paranormal investigator, research fellow at the Committee for Skeptical Inquiry and deputy editor of the Skeptical Inquirer, and author of the Discovery News article, “Why People Believed Boy’s ‘Visit to Heaven’ Story”

•   Greg Garrett – Professor of English at Baylor University, writer on books, culture and religion for the Huffington Post, and author of Entertaining Judgment: The Afterlife in Popular Imagination

v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} 0 0 1 274 1564 SETI Institute 13 3 1835 14.0 Normal 0 false false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;}

•   Steven Novella – Professor of neurology at Yale University School of Medicine and host of the “Skeptic’s Guide to the Universe” podcast

Pages


Subscribe to SETI Institute aggregator