Clipmarks | Aribeth's 'science' clips

Could Jupiter wreck the solar system?

Sun, 04 May 2008 12:13:24 GMT

clipped by: Aribeth
clipper's remarks: "So what's the likelihood Mercury could crash into the Earth? If it did, the asteroid that most likely wiped out the dinosaurs will seem like a drop in the ocean compared with a planet 4880 km in diameter slamming into us. There will be very little left after this wrecking ball impact.

But here's the kicker: There is only a 1% chance that these gravitational instabilities of the inner Solar System are likely to cause any kind of chaos before the Sun turns into a Red Giant and swallows Mercury, Venus, Earth and Mars in 7 billion years time. So, no need to look out for death-wish Mercury quite yet… there's a very low chance that any of this will happen. But some good news for Mars; the researchers have also found that if the chaos does ensue, the Red Planet may be flung out of the Solar System, possibly escaping our expanding Sun. So, let's get those Mars colonies started! Well, within the next few billions of years anyhow…"

Good stuff for the next science-fiction movie

Clip Source: www.universetoday.com

Could Jupiter Wreck the Solar System?

Happily orbiting the Sun, the eight planets (plus Pluto and other minor planets) appear to have a high degree of long-term gravitational stability. But Jupiter has a huge gravitational influence over its siblings, especially the smaller planets.

The huge gravitational pull of Jupiter seems to be bullying Mercury into an increasingly eccentric death-orbit, possibly flinging the cosmic lightweight into the path of Venus. To make things worse, there might be dire consequences for Earth…

The researchers

Jacques Laskar

Konstantin Batygin

and Gregory Laughlin

formulate four possible scenarios as to what may happen as Mercury gets disturbed:

Mercury will crash into the Sun
Mercury will be ejected from the solar system altogether
Mercury will crash into Venus
Mercury will crash into Earth

The last option is obviously the worst case scenario for us, but all will be bad news for Mercury, the small planet's fate appears to be sealed.

Tags: science, space, astronomy

The man who invented Mars

Mon, 28 Apr 2008 18:02:29 GMT

clipped by: Aribeth
clipper's remarks: It is Lowell's vision of Mars that has enthralled and inspired earthlings ever since.In 1895, Lowell published a book about what he believed he saw.He became famous and immensely popular.Lowell was born at 131 Tremont Street in Boston on March 13,1855,into a family at the pinnacle of what passed for American aristocracy.

The appearance of Lowell's book about Mars in 1895 came at a time of canal-building on earth. The Suez had recently been constructed; the Panama was in the works. For both Lowell and his adoring public, the prospect of canals on a neighboring planet was too captivating to dismiss.

He published his second book about the Red Planet, Mars and Its Canals, in 1906.In 1908, he published his third and final book on the planet, Mars as the Abode of Life.

Back at his observatory on Mars Hill, Lowell renewed his attention to another matter: the possibility of a ninth planet beyond Neptune, which he called "Planet X."

Clip Source: www.boston.com

The Man Who Invented Mars

Long before the space race and space shuttle, a brilliant, wealthy, charming Boston Brahmin named Percival Lowell popularized the idea that we are not alone in the universe.

At left, a colorized version of a 1905 drawing of Mars by Lowell; at right, an artist’s concept of the Phoenix Mars lander.

AT 7:36 P.M. ON May 25, if all goes well, a stranger from Earth will land near the north pole of Mars. It is called Phoenix.

Somewhere, a 19th century Boston Brahmin named Percival Lowell will be smiling.

Long before NASA was established in 1958

Percival Lowell devoted much of his career and considerable fortune to trying to prove that Mars hosted intelligent life. Viewed through his telescopes, the ancient, baleful Red Planet was about the size of a dime.

Lowell believed he was seeing a network of canals on its surface. Therefore, he declared, Mars holds intelligent life. It is not necessarily like human life, he emphasized, but it is intelligent enough to build canals.

Tags: science, space, astronomy

Robin Hanson on the "Great Filter"

Mon, 28 Apr 2008 07:37:50 GMT

clipped by: Aribeth
clipper's remarks: there is a "Great Filter" along the path between simple dead stuff and explosive life. The vast vast majority of stuff that starts along this path never makes it. In fact, so far nothing among the billion trillion stars in our whole past universe has made it all the way along this path.... [O]ne or more of these steps is much more improbable than it otherwise looks. If it is one of our past steps, such as the development of single-cell life, then we shouldn't expect to see such independently evolved life anywhere within billions of light years from us. But if it is a step between here and a choice to explode that is very improbable, we should fear for our future.... Optimism (as defined here) regarding our future is directly pitted against optimism regarding the ease of previous evolutionary steps. To the extent those successes were easy, our future failure to explode is almost certain...

Clip Source: econ161.berkeley.edu

The Great Filter - Are We Almost Past It?

Robin Hanson argues that either (a) our emergence as intelligent humans on the earth was very, very, very improbable and unlikely, but that our future (at least in terms of expansion of human-settled habitats throughout the universe) is bright, or (b) emergence as intelligent humans on the earth was relatively easy, but that our future is dim (and perhaps that our extinction is all but guaranteed).

The Great Filter: Consider our best-guess evolutionary path to an explosion which leads to visible colonization of most of the visible universe:

1. The right star system (including organics)
2. Reproductive something (e.g. RNA)
3. Simple (prokaryotic) single-cell life
4. Complex (archaeatic & eukaryotic) single-cell life
5. Sexual reproduction
6. Multi-cell life
7. Tool-using animals with big brains
8. Where we are now
9. [Interstellar] Colonization explosion

The Great Silence implies that one or more of these steps are very improbable;

Tags: theory, science, space colonization, biology, evolution

Crew Earth Observations 'Top Ten' Photos

Sat, 26 Apr 2008 11:09:10 GMT

clipped by: Aribeth

Clip Source: www.nasa.gov

Crew Earth Observations 'Top Ten' Photos

From the International Space Station Astronaut Photography Collection

Eruption of Cleveland Volcano, Aleutian Islands, Alaska

acquired shortly after the beginning of the eruption, captures the ash plume moving west-southwest from the summit vent

this image shows the limb of the Earth at the bottom transitioning into the orange-colored troposphere, the lowest and most dense portion of the Earth's atmosphere

nighttime view of Los Angeles, California

Aurora Borealis and lights in Finland, Russia, Estonia and Latvia

is a glimpse of the barren moon through the Earth’s limb

Mt. Everest and Makalu

green aurora dancing over the night side of the Earth just after sunset on February 16, 2003

Bernese Alps, Switzerland

Nukuoro Atoll, Federated States of Micronesia

Harrat Khaybar, Saudi Arabia

The western half of the Arabian peninsula contains

extensive lava fields known as haraat

One such field is the 14,000-square kilometer Harrat Khaybar

Tags: images, science, space

Strange things happen at full moon

Tue, 22 Apr 2008 18:09:25 GMT

clipped by: Aribeth
clipper's remarks: On the moon's dayside this effect is counteracted somewhat by sunlight: Photons knock electrons back off the surface, lessening the negative charge. But on the night side, electrons accumulate and the charge can climb to thousands of volts.

The extreme differences in charge might cause dust to fly from the negative night side to the less-negative day side, becoming strongest along the regions where the sun is rising or setting.

Astronauts walking on the charged terrain might get electrified like sock from a hot dryer. "Touching another astronaut, a doorknob, a piece of sensitive electronics — any of these simple actions could produce an unwelcome zap."

Clip Source: www.space.com

Strange Things Happen at Full Moon

At full moon, our favorite satellite is whipped by Earth's magnetotail, causing lunar dust storms and discharges of static electricity.

The effect on the moon was first noticed in 1968, when NASA's Surveyor 7 lander photographed a strange glow on the horizon after dark. Nobody knew what it was. Now scientists think it was sunlight scattered by electrically charged moon dust floating just above the surface.

Clip Source: www.space.com

How it works

Our entire planet is enveloped in a bubble of magnetism generated by the rotating core. The solar wind, a stream of charged particles, pushes the bubble away from the sun and creates a long tail of magnetized material downstream.

At full moon, the moon passes through a huge "plasma sheet" — hot charged particles trapped in the tail. The lightest and most mobile of these particles, electrons, pepper the moon's surface and give the moon a negative charge, the researchers explained.

Clip Source: www.space.com

Tags: science, space

Life on the edge

Sun, 27 Apr 2008 07:27:37 GMT

clipped by: Aribeth
clipper's remarks: That throws up a tricky problem for engineers sending space craft to explore these alien worlds. What if the craft were to carry its own cargo of Earth microbes which set up home there?One major problem for any accidental interplanetary microbe would be how to survive the punishing radiation bombardment in space. Most would be rapidly frazzled en route. Most, but not all.

Deinococcus radiodurans, nicknamed "Conan the Bacterium", is listed by the Guinness Book of World Records as the "world's toughest bacterium". By rapidly replacing its DNA, it can survive cold, dehydration, vacuum, acid and a hefty radiation dose. Its Latin name means "terrifying berry that withstands radiation".

Clip Source: www.guardian.co.uk

Life on the edge

Even in the world's harshest environments there are creatures that cling to life equipped with extraordinary survival capabilities.

Welcome to the bizarre and uncomfortable (for us) world of the extremophiles - hardy organisms that thrive under the most punishing conditions.

Apart from cold-loving species there are organisms adapted to extreme heat, dryness, saltiness and even high radioactivity.

The most impressive hyperthermophile is the recently discovered Strain 121. It is able to keep dividing even at water temperatures of 121C (hence its name). At this depth, due to the extreme pressure, water does not boil.

halophiles or salt-lovers, have adapted to thrive in salt concentrations 10 times those in sea water, or even higher - for example in Utah's Great Salt Lake

With so many super-hardy creatures on our doorstep here on Earth, the possibility that simple life-forms exist somewhere in the solar system or beyond looks much more likely.

Tags: science, biology

Raindrops on roses

Sat, 26 Apr 2008 12:55:50 GMT

clipped by: Aribeth
clipper's remarks: The team tried to replicate the effect.They put some polyvinyl alcohol onto rose petals and allowed it to set, then peeled off a thin plastic cast of the petal surface.This film had the same properties as the rose petal:the film could hold droplets of between 3-5 microlitres even when held upside down.

It seems that the physical shape of the surface is much more important than any chemical properties of the material in creating 'stickiness',says Ronald Fearing, a biomimetic engineer at the University of California at Berkeley.

For a rose, this stickiness might come in handy as reflective water drops that glisten in the Sun might attract pollinating insects. In the lab, such materials might be useful for 'lab on a chip' devices that need to hold and shunt around tiny quantities of liquid without leaking or being contaminated by nearby materials. "These findings present many interesting applications in microfluid handling," says Fearing.

Clip Source: www.nature.com

Raindrops on roses

Behind the natural beauty of a rosebud covered in dew drops lies a decades-old mystery: why don't the tiny droplets fall off, even when the flower is turned upside down?

The beading of water droplets on natural materials is not a rare thing.

But on many flowers and leaves the droplets slide off with the slightest tremble

because the surfaces are very rough and spiky at the microscopic scale, and the tips of the spikes are covered in wax.

The water molecules therefore come into contact with only a tiny fraction of the surface, and then only to water-repelling wax.

Lin Feng and her colleagues at Tsinghua University in Beijing found that although rose petals are coated with similar projections, they have wide, gentle-sloping troughs between the spikes, and no wax. The spikes keep the dew drops in a spherical shape, but the water 'leaks' into the troughs between spike-covered bumps, giving a bit of 'stick' and stopping a small droplet from rolling around (see diagram).

Tags: science

What planet is this?

Sun, 20 Apr 2008 19:19:51 GMT

clipped by: Aribeth

Clip Source: www.ironicsans.com

Waterworld

What planet is this?

It’s Earth, of course, viewed from around 9900 miles above a small island called Tetiaora, one of the few bits of land on this half of the planet.

It’s weird that there’s a view of earth that’s almost entirely water.

Tags: photo, image, french polynesia, atoll, science

Earth could seed Titan with life

Sat, 19 Apr 2008 20:24:29 GMT

clipped by: Aribeth
clipper's remarks: Dr Gladman's team calculated that up to 20 terrestrial rocks from a large impact on Earth would reach Titan. These would strike Titan's upper atmosphere at 10-15 km/s. At this velocity, the cruise down to the surface might be comfortable enough for microbes to survive the journey.But the news was more bleak for Europa. By contrast with the handful that hit Titan, about 100 terrestrial meteoroids hit the icy moon.

"It's frustrating if you're a microbe that's been wandering the Universe for a million years to then die striking the surface of Europa," Dr Gladman mused.Asked after his presentation by one scientist whether he thought microbes would be able to survive Titan's freezing temperatures, Dr Gladman answered: "That's for you people to decide, I'm just the pizza delivery boy."

Clip Source: news.bbc.co.uk

Terrestrial rocks blown into space by asteroid impacts on Earth could have taken life to Saturn's moon Titan, scientists have announced.

Earth microbes in these meteorites could have seeded the organic-rich world with life, researchers believe.

the impact on Earth that killed off the dinosaurs could have ejected enough material for some to reach far-off moons such as Titan

The theory of panspermia holds that life on planets like Earth and Mars was seeded from space, perhaps hitching a ride on meteorites and comets.

To get terrestrial, life-bearing rocks to escape the Earth's atmosphere and reach space requires an impact by an asteroid or comet between 10 and 50km across.

Million-year journey

One of them is the asteroid strike 65 million years ago, which punched a crater between 160 and 240km wide in what is today the Yucatan Peninsula, Mexico.

targets

Titan and Europa

Titan is rich in organic compounds

potential energy source for primitive life forms

Europa

thought to harbour a liquid water ocean

Tags: science, space

Why we may overlook extra-terrestrial life

Thu, 17 Apr 2008 10:59:58 GMT

clipped by: Aribeth
clipper's remarks: Ammonia, for example, has many of the same properties as water. An ammonia or ammonia-water mixture, stays liquid at much colder temperatures than plain water.Hydrogen fluoride methanol, hydrogen sulfide, hydrogen chloride, and formamide have all been suggested as suitable solvents that could theoretically support alternative biochemistry. All of these “water replacements” have pros and cons when considered in our terrestrial environment. What needs to be considered is that with a radically different environment, comes radically different reactions. Water and carbon might be the very last things capable of supporting life in some extreme planetary conditions. In any case, it is not beyond the realm of feasibility that our first encounter with extra-terrestrial life will not be a solely carbon-based occasion.

Clip Source: www.dailygalaxy.com

Non-Carbon Lifeforms -Why We May Overlook Extra-terrestrial Life

Carbon is great molecular glue—there’s not doubt about it. Just add water and you’ve got life. Well, maybe it’s not quite that simple, but carbon and water do seem to be a winning combo, at least on planet Earth. That may be why we’ve been limiting ourselves in our search for . The carbon/water combo has worked so well for our own conditions, that we simply can’t imagine anything else supporting life.

other options do exist besides water and carbon

there are several atoms and solvents that could potentially spawn life

Various elements become more stable and capable of forming complex molecules when under strange (from a human perspective) thermal and atmospheric conditions.

silicone-based chemicals would be more stable than equivalent hydrocarbons in a sulphuric-acid-rich setting

counter-intuitive elements such as arsenic

Chlorine and sulfur

Nitrogen and phosphorus

Isn’t at least water essential to life? Not necessarily.

Tags: science, chemistry, biochemistry

Pluto lovers,don't despair

Fri, 11 Apr 2008 08:13:29 GMT

clipped by: Aribeth

Clip Source: www.sciam.com

Is Rekindling the Pluto Planet Debate a Good Idea?

Pluto lovers, don't despair: Researchers have not given up the fight for the former ninth planet. Many of them put up a fuss two years ago when the International Astronomical Union (IAU) downgraded Pluto and other smaller bodies in the solar system to the status of mere dwarf planets. Now they plan to revive the debate, this time under the banner of public understanding of science.

Researchers on both sides of the issue are set to gather in August at Johns Hopkins University Applied Physics Laboratory in Laurel, Md., for what's being called "The Great Planet Debate: Science as Process."

Pluto has always stood out from the other planets. At roughly a fifth the mass of the moon, it is the largest of the icy bodies that make up the Kuiper belt beyond Neptune's orbit. Unlike the four inner (terrestrial) planets, it has a tenuous atmosphere at best.

Tags: astronomy, science

The Ancient Mechanics and How They Thought

Wed, 02 Apr 2008 11:12:51 GMT

clipped by: Aribeth
clipper's remarks: He also majored in astronomy as an undergraduate, and about nine years ago, feeling science-deprived, he joined a multinational research endeavor called the Archimedes Project, based at the Max Planck Institute for the History of Science in Berlin.

The Archimedes team studies the history of mechanics, how people thought about simple machines like the lever, the wheel and axle, the balance, the pulley, the wedge and the screw and how they turned their thoughts into theories and principles.

The textual record begins with “Mechanical Problems,” moves to Rome and then through the medieval Islamic world to the Renaissance. It ends, finally, with Newton, who described many of the basic laws of mechanics in the 18th century.

By following the historical record, the Archimedes researchers have discovered that the evolution of physics — or, at least, mechanics — is based on an interplay between practice and theory.

Clip Source: www.nytimes.com

LAW OF THE LEVER On triremes, the end oarsmen were the most effective.

“Think of the oar as a lever,” Prof. Mark Schiefsky of the Harvard classics department said. “Think of the oarlock as a fulcrum, and think of the sea as the weight.”

The longer the lever arm on the rower’s side of the fulcrum, the easier to move the weight. In the middle of the ship, as the rowers knew, the distance from hands to oarlock was longest.

This explanation is given in Problem 4 of the classical Greek treatise “Mechanical Problems,” from the third century B.C., the first known text on the science of mechanics and the first to explain how a lever works. It preceded, by at least a generation, Archimedes’ “On the Equilibrium of Plane Figures,” which presented the first formal proof of the law of the lever.

EARTHMOVER Archimedes said he could move the Earth if given a place to stand.

Dr. Schiefsky teaches Greek and Latin as his day job and reads Thucydides and Sophocles in ancient Greek for fun.

Tags: physics, ancient mechanics, science, classics, research, archimedes project

A New Kind of Rainbow : The Brainbow

Sun, 11 Nov 2007 12:55:13 GMT

clipped by: Aribeth

Clip Source: www.medgadget.com

A team of Harvard scientists implanted genes into mice that coded for three color fluorescing proteins in their brains, and had them randomly express themselves, producing up to 90 different color shades.

Clip Source: www.cbc.ca

"Brainbow should help us much better map out the brain and nervous system's complex tangle of neurons," said researcher Jeff Lichtman.

It could also see interactions among neighbouring non-neural cells and neurons and even help scientists identify how brain wiring reacts in many different diseases.

Clip Source: www.guardian.co.uk

Tags: science, neuroscience

Ancient Blueprints of Calculus Uncovered in Archimedes Text

Sat, 06 Oct 2007 19:20:11 GMT

clipped by: Kore7
clipper's remarks: Details have been released from the nine-year-long reconstruction project to recover the Greek mathematician's writings from this one-of-a-kind find and the results are fascinating.

Buried beneath the surface of this gilded palimpsest, researchers discovered more extensive demonstrations of concepts such as infinite series, approximations, limits, and integral calculus than had been known to exist in ancient times.

Archimedes wrote The Method almost two thousand years before Isaac Newton and Gottfried Wilhelm von Leibniz developed calculus in the 1700s. Reviel Netz, an historian of mathematics at Stanford University who transcribed the text, says that the examination of Archimedes' work has revealed "a new twist on the entire trajectory of Western mathematics."

Clip Source: www.sciencenews.org

A long-lost text by the ancient Greek mathematician shows that he had begun to discover the principles of calculus.

The top layer of writing in this 700-year-old book describes Christian prayers. But underneath, almost obliterated, are the only surviving copies of many of the works of the ancient Greek mathematician Archimedes.

The picture on the left is an ordinary photograph, with the Archimedes text barely visible. The picture on the right is a multi-spectral image, and the Archimedes text and diagrams are mostly legible.

Sometime after Johan Heiberg examined the book in 1906, someone painted gold-leaf images over four of the pages (left). Multispectral imaging couldn't peer beneath the reflective metal paint, but x-ray fluorescence imaging revealed the underlying text (right).

Archimedes computed the area of the curved figure (left) by enclosing it in a bigger one with straight edges (right). He then examined random slices to compute the volume—using the concept of actual infinity.

Tags: math, science, archimedes, calculus, infinity, greek, ancient, history, x-ray, book

Brain Can Only Pay Attention for 40 MInutes

Sat, 20 Oct 2007 04:26:33 GMT

clipped by: AndreaJoRush
clipper's remarks: And I thought I must have ADD (I probably do) because I could not pay attention in graduate math classes for more than about 45 minutes. It seems like I was doing a lot better than I thought!

Clip Source: www.sciencedaily.com

Psychologists are finding out that even when people try to focus on a task they tend to lose concentration within 40 minutes, and sometimes as little as 10 minutes. The studies are based on a new technique, called transcranial Doppler sonography, that uses ultrasound to monitor blood flow velocity in the brain. The technique could be turned into a warning system for workers who perform critical tasks -- such as pilots or air traffic controllers -- or even for drivers.

Distractions can break anyone's concentration, but new research shows what happens in your brain can, too.

The phenomenon is such that the more you look, the less you see

transcranial Doppler sonography (TDS). The device measures blood flow velocity in the brain

researchers saw a decrease in blood-flow velocity over time, and, therefore, a decrease in attention

Warm believes the study results can be helpful for the military, security workers, air traffic controllers and many others

Tags: attention, brain, science