The Science of Reality

the-science-llama: Wave at SaturnWho wants to be in the world’s...

Wed, 19 Jun 2013 00:15:01 -0400

Wave at Saturn
Who wants to be in the world’s biggest class picture?
On July 19, NASA’s Cassini spacecraft will take a picture of Earth from nearly 900 million miles away.

Cassini will start obtaining the Earth part of the mosaic at 2:27 p.m. PDT (5:27 p.m. EDT or 21:27 UTC) and end about 15 minutes later, all while Saturn is eclipsing the sun from Cassini’s point of view.

A simulated view from the Cassini spacecraft when it will take the photo

alittlecoconuttart: [Article excerpt] New Study Shows Hillary...

Wed, 19 Jun 2013 00:00:51 -0400

alittlecoconuttart:

[Article excerpt]
New Study Shows Hillary Clinton’s Face Makes Women More Confident
Tess VandenDolder Apr 25th at 1:07 pm

In the study individual men and women were asked to give a speech in front of a panel of six strangers. For some there was a picture of Bill Clinton on the back wall and for others there was a picture of Hillary. Overall the men spoke longer and were judged as better speakers than the women, except for the group of ladies who spoke while looking into Hillary’s baby blues. That group blew the men out of the water as far as the length of their speeches and overall confidence and success in conveying their ideas publicly.

The conclusion researchers drew from this study was that when women are exposed to powerful female role models in leadership positions they gained instant boosts in confidence and the ability to achieve at high levels. ”Female political role models can inspire women and help them cope with stressful situations that they encounter in their careers, such as public speaking,” the authors of the study wrote. ”A lack of female powerful role models leads to a vicious circle, because if women fail to take leadership positions, they also fail to provide role models for junior women to follow.”

“They go on to recommend that ‘active steps should be taken in order to increase the number of women in leadership positions, which would consequently increase their visibility and empower other women on their path to leadership.’ ” via POPSCI

supraspectra: Top: Space Shuttle Atlantis docked with Mir on 4...

Tue, 18 Jun 2013 21:26:17 -0400

supraspectra:

Top: Space Shuttle Atlantis docked with Mir on 4 July 1995. Cosmonauts Anatoliy Y. Solovyev and Nikolai M. Budarin, who had arrive onboard Atlantis five days earlier, took Soyuz TM-21 for a fly-around photo survey prior to Atlantis undocking for her return to Earth. This was the first time a shuttle had docked with Mir.

Bottom: Two shots of the Space Shuttle Endeavour docked with the ISS, as photographed by the departing Soyuz TMA-20 spacecraft on 23 May 2011, during the STS-134 mission. (There are a lot more from this fly-around here)

jtotheizzoe: A “RoboBee” and a synthetic insect eye reported in...

Tue, 18 Jun 2013 19:51:46 -0400

jtotheizzoe:

A “RoboBee” and a synthetic insect eye reported in the same week? Sounds like a full-fledged man-made insect is just around the corner!

University of Illinois-UC researchers built a synthetic compound eye that, instead of focusing on the central field of view like our eyes, can discern depth and shape along its full scope. The resolution is only about that of a rather small ant, but there’s hope it could one day include as many facets as a bee or dragonfly eye. That research is reported in Nature.

And in this week’s Science, Harvard roboticists report the first controlled flight of a coin-size miniature aerial vehicle (MAV) based on the flight physics of insect wings. The construction is based on that used to make pop-up books, an odd advance in micro-building techniques that gave them the precision needed to get it off the ground. The wings aren’t as flexible or functional as real insect wings, but it’s the smallest piloted vehicle ever made. That research is reported in this week’s Science.

Now we just need to extend that compound eye camera’s sensitivity into the UV range, attach it to the RoboBee, and we’ll finally be able to see flowers like we imagined in this YouTube episode of It’s Okay To Be Smart (and maybe synthetically pollinate them!!)

I, for one, welcome our tiny, buzzing underlings.

science-junkie: Gene survival and death on the human Y...

Tue, 18 Jun 2013 18:18:00 -0400

science-junkie:

Gene survival and death on the human Y chromosome
By M. Wilson Sayres

In humans, genetic females have two X chromosomes and genetic males have one X chromosome and one Y chromosome:
You might have noticed from the cartoon above that the human Y is much smaller than the human X. But, it wasn’t always this way. Ancestrally, the human X and Y were the same size, and had the same genes. Over time, however, the Y has shrunk, but both the X and Y have also gained some genes. To better understand how the X and Y became so different, and how the evolution of the two sex chromosomes are correlated, we asked three main questions:

What has been lost from the Y?
To know which genes were lost, we first had to identify which genes were on the ancestral sex chromosome pair. By comparing the genes on the human X with the genes the X in other species, we identified a set of genes that were likely on the ancestral X chromosome: 600 in total. Then, by searching the Y chromosome for the relics of all of these genes, we identified three classes of sex-linked genes. We should think of each of the 600 ancestral genes as a pair (with one copy on the X, and one on the Y). All of these pairs have a working copy on the human X. Some pairs have a working (functional) copy on the Y, some have a broken copy on the Y (degraded), and some are missing their Y-copy.

Many genes have been lost from the ancestral Y, but a few persist. So, while some Y-linked genes have survived (I have another paper discussing this), and there have been some unique additions to the Y chromosome, we can see that the Y has lost functional capabilities for 96.83% of the genes that it once shared with the X. Wow!

Are there indicators of whether a Y-linked gene will be retained?
We can learn about the evolution of the sex chromosomes by studying differences between classes of sex-linked genes defined above. Specifically we asked, do features of X-linked genes suggest whether their Y-linked partner are retained or lost? In some cases, yes, they do.

First, we found that human X-linked genes with very few changes across mammals were more likely to have a working Y copy. So, if a gene is important enough to survive over long evolutionary time in roughly the same condition across very different species, then it might be very useful to the organism, so it would be important to have that gene in a working form in both males and females in the same species (human).

Second, we looked at expression. Genes can sometimes be “on” (which we would call expressed) or “off” (not expressed), but more often they can fall within a range. It’s like a light with a dimmer switch. The light can be turned on very brightly, but can also dimmed to a very low level without being “off”. We found that X-linked genes that were highly expressed (bright) were more likely to have a working Y copy. This might mean that, for these genes, the level of “brightness” or expression is important, so that it is highly beneficial for these genes to be working very hard in both females and in males.

Does gene loss on the Y affect the evolution the X?
Okay, so some features of the X-linked partner might predict whether it’s Y-linked partner will survive, but is there any feedback from the Y back to the X chromosome? Yes!

Let’s think back to that first picture: females have two “big” X chromosomes, while males have one “big” X and one “little” Y. And, I’ve shown you that the Y chromosome has lost (either because of broken copies, or completely lost) almost 97% of the genes that it once shared with the X. This might lead you to believe that there are more genes expressed in females than in males. But, in many mammals, females silence most of the genes on one of their X chromosomes (X-inactivation), to equalize the dosage of genes expressed between males and females.

Although it has been hypothesized, we showed that the pattern of genes subject to silencing in females among the three classes above is consistent with a process whereby silencing evolves in response to gene loss on the Y chromosome. Moreover, this pattern suggests that some amount of time must pass to allow the signal (that the Y-linked partner is no longer working) to reach the X-chromosome before silencing can occur.

The paper is open access, so if you are curious, you can read it on Molecular Biology and Evolution.

Source: pandasthumb.org

ikenbot: International Space Station in Color Copyright:...

Tue, 18 Jun 2013 16:43:29 -0400

ikenbot:

International Space Station in Color

Copyright: Francesco di Biase - Italy - Private Observatory

I know I’m always saying this but it never gets old; Chris Hadfield is in there!

Cassini Probe to Take Photo of Earth From Deep Space [Image...

Tue, 18 Jun 2013 15:50:18 -0400

Cassini Probe to Take Photo of Earth From Deep Space

[Image credit: NASA/JPL-Caltech]

“NASA’s Cassini spacecraft, now exploring Saturn, will take a picture of our home planet from a distance of hundreds of millions of miles on July 19. NASA is inviting the public to help acknowledge the historic interplanetary portrait as it is being taken.

Earth will appear as a small, pale blue dot between the rings of Saturn in the image, which will be part of a mosaic, or multi-image portrait, of the Saturn system Cassini is composing.

“While Earth will be only about a pixel in size from Cassini’s vantage point 898 million [1.44 billion kilometers] away, the team is looking forward to giving the world a chance to see what their home looks like from Saturn,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We hope you’ll join us in waving at Saturn from Earth, so we can commemorate this special opportunity.”

Cassini will start obtaining the Earth part of the mosaic at 2:27 p.m. PDT (5:27 p.m. EDT or 21:27 UTC) and end about 15 minutes later, all while Saturn is eclipsing the sun from Cassini’s point of view. The spacecraft’s unique vantage point in Saturn’s shadow will provide a special scientific opportunity to look at the planet’s rings. At the time of the photo, North America and part of the Atlantic Ocean will be in sunlight.

Unlike two previous Cassini eclipse mosaics of the Saturn system in 2006, which captured Earth, and another in 2012, the July 19 image will be the first to capture the Saturn system with Earth in natural color, as human eyes would see it. It also will be the first to capture Earth and its moon with Cassini’s highest-resolution camera. The probe’s position will allow it to turn its cameras in the direction of the sun, where Earth will be, without damaging the spacecraft’s sensitive detectors.”

To learn more about the public outreach activities associated with the taking of the image, visit:http://saturn.jpl.nasa.gov/waveatsaturn .

For more information about Cassini, visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

laboratoryequipment: Antibacterial Soap Has Never Been Studied...

Tue, 18 Jun 2013 15:09:09 -0400

laboratoryequipment:

Antibacterial Soap Has Never Been Studied by FDA

It’s a chemical that’s been in U.S. households for more than 40 years, from the body wash in your bathroom shower to the knives on your kitchen counter to the bedding in your baby’s basinet.

But federal health regulators are just now deciding whether triclosan — the germ-killing ingredient found in an estimated 75 percent of antibacterial liquid soaps and body washes sold in the U.S. — is ineffective, or worse, harmful.

Read more: http://www.laboratoryequipment.com/news/2013/05/antibacterial-soap-has-never-been-studied-fda

abcstarstuff: Feynman’s double-slit experiment brought to...

Tue, 18 Jun 2013 13:34:40 -0400

abcstarstuff:

Feynman’s double-slit experiment brought to life

The precise methodology of Richard Feynman’s famous double-slit thought-experiment – a cornerstone of quantum mechanics that showed how electrons behave as both a particle and a wave – has been followed in full for the very first time.

Although the particle-wave duality of electrons has been demonstrated in a number of different ways since Feynman popularised the idea in 1965, none of the experiments have managed to fully replicate the methodology set out in Volume 3 of Feynman’s famous Lectures on Physics.

“The technology to do this experiment has been around for about two decades; however, to do a nice data recording of electrons takes some serious effort and has taken us three years,” said lead author of the study Professor Herman Batelaan from the University of Nebraska-Lincoln.

“Previous double-slit experiments have successfully demonstrated the mysterious properties of electrons, but none have done so using Feynman’s methodology, specifically the opening and closing of both slits at will and the ability to detect electrons one at a time.

“Akira Tonomura’s brilliant experiment used a thin, charged wire to split electrons and bring them back together again, instead of two slits in a wall which was proposed by Feynman. To the best of my knowledge, the experiments by Guilio Pozzi were the first to use nano-fabricated slits in a wall; however, the slits were covered up by stuffing them with material so could not be open and closed automatically.”

In their experiments, which have been published today, Thursday 14 March, in the Institute of Physics and German Physical Society’s New Journal of Physics, Batelaan and his team, along with colleagues at the Perimeter Institute of Theoretical Physics, created a modern representation of Feynman’s experiment by directing an electron beam, capable of firing individual electrons, at a wall made of a gold-coated silicon membrane.

The wall had two 62-nm-wide slits in it with a centre-to-centre separation of 272 nm. A 4.5 µm wide and 10 µm tall moveable mask, controlled by a piezoelectric actuator, was placed behind the wall and slid back and forth to cover the slits.

“We’ve created an experiment where both slits can be mechanically opened and closed at will and, most importantly, combined this with the capability of detecting one electron at a time.

“It is our task to turn every stone when it comes to the most fundamental experiments that one can do. We have done exactly that with Feynman’s famous thought-experiment and have been able to illustrate the key feature of quantum mechanics,” continued Batelaan.

Feynman’s double-slit experiment

In Feynman’s double-slit thought-experiment, a specific material is randomly directed at a wall which has two small slits that can be opened and closed at will – some of the material gets blocked and some passes through the slits, depending on which ones are open.

Based on the pattern that is detected beyond the wall on a backstop – which is fitted with a detector – one can discern whether the material coming through behaves as either a wave or particle.

When particles are fired at the wall with both slits open, they are more likely to hit the backstop in one particular area, whereas waves interfere with each other and hit the backstop at a number of different points with differing strength, creating what is known as an interference pattern.

In 1965, Feynman popularised that electrons – historically thought to be particles – would actually produce the pattern of a wave in the double-split experiment.

Unlike sound waves and water waves, Feynman highlighted that when electrons are fired at the wall one at a time, an interference pattern is still produced. He went on to say that this phenomenon “has in it the heart of quantum physics [but] in reality, it contains the only mystery.”

Now You Can Buy 3D Printers From Staples

Mon, 17 Jun 2013 21:26:04 -0400

Now You Can Buy 3D Printers From Staples:

futurist-foresight:

Staples to sell 3D Printers soon. Superb news and another indication of the emergence of this technology.

“Image via Getty, Emmanuel Dunand”

“Staples, which announced in November that it planned to bring the devices to its European stores, will be selling the Cube 3D Printer from 3D Systems for $1,299. The printer has built-in WiFi and comes with more than two dozen 3D design templates, with more available to download online. Staples will also sell accessories for the 3D printers like plastic cartridge refills.” - Mashable

"The Louisiana Science Education Act does more than harm the potential of Louisiana’s students. It is..."

Mon, 17 Jun 2013 19:52:01 -0400

“The Louisiana Science Education Act does more than harm the potential of Louisiana’s students. It is already directly impacting the state’s economy. Louisiana State University’s former graduate dean of science, Kevin Carman, testified before the state legislature in 2012 that top scientists had left the university citing the Louisiana Science Education Act as a reason. Other scientists chose to accept jobs elsewhere, because they didn’t want to come to a state with a creationism law. Carman said: “teaching pseudo-science drives scientists away.”

Louisiana’s third largest industry is tourism, and the state generates millions of dollars each year from conventions. After the Louisiana Science Education Act was passed, the Society for Integrative and Comparative Biology cancelled a scheduled convention in New Orleans in 2011, costing the city an estimated $2.9m. The society launched a boycott of Louisiana, and the state has become less competitive at attracting certain conventions because of its anti-science stance.

Thankfully, the boycott of New Orleans has ended, because the New Orleans city council has endorsed a repeal of the Louisiana Science Education Act and the Orleans Parish School Board banned the teaching of creationism in its schools. The boycott on the rest of the state still remains, however.”

- Louisiana counts the cost of teaching creationism – in reputation and dollars | Zack Kopplin | Comment is free | guardian.co.uk (via robot-heart-politics)

spaceplasma: Exploding star remnants found in fossilized...

Mon, 17 Jun 2013 18:17:47 -0400

Example of a magnetotactic bacterium containing a chain of magnetosomes

spaceplasma:

Exploding star remnants found in fossilized bacteria

Thousands of metres below the sea, trapped in the fossilized remains of ancient bacteria, exists the iron remnants of a supernova explosion that happened millions of years ago. An imprint, here on Earth, of a dying star.

Iron-60, an isotope of iron created only in supernovae, has been found in fossilised seabed bacteria. The preliminary findings, announced by Shawn Bishop of the Technical University of Munich at a 14 April meeting of the American Physical Society in Colorado, may be the first time that a specific star’s debris has been found in our fossil record.

Iron-60’s half-life is relatively short when compared to the age of our solar system, so traces of the isotope on Earth suggests a direct interaction with a supernova in the planet’s history. The researchers searched for the isotope in fossils from seabed samples between 1.7 million to 3.3 million years old. They likely found traces of the isotope in fossils around 2.2 million years old.

The bacteria containing the Iron-60 are magnetotactic; they are strange organisms live in the seabed and align themselves with the Earth’s magnetic field. They extract iron from the water and sediment around them and create iron oxide crystals that are then preserved in the fossil record.

“For me, philosophically, the charm is that this is sitting in the fossil record of our planet,” said Bishop in a Nature.com report. The isotope had previously been discovered in seabed samples, but not in the fossil record.

“We are all, as Carl Sagan put it, stardust,” Bishop told Wired.co.uk. “[We have now] likely discovered, within crystal nano-fossils left behind by primitive bacteria, […] still-live radioactive atoms that can only have been synthesized within the same kind of nuclear furnace — an exploding star — that forged the elements from which all live on Earth is made. The cycle comes full-circle.”

It has been estimated that the supernova happened around 2.2 million years ago, and that the stream of cosmic rays would have had an effect on the Earth’s atmosphere by increasing cloud cover. The supernova responsible for depositing the iron-60 has not yet been found, but possible suspects have been identified in the nearby Scorpius-Centarus association.

This isn’t the first time that distant astronomical events have made an impact on Earth. In 2012, researchers found a surplus of radioactive atoms in Japanese trees, hinting at a violent cosmic event around 1,200 years ago.

Dim Star Becomes 7 Times Hotter in 160 Seconds Image...

Mon, 17 Jun 2013 17:17:24 -0400

Dim Star Becomes 7 Times Hotter in 160 Seconds

Image Credit: Casey Reed/NASA.

“Talk about a celestial mood swing: Scientists using the SCORPIO camera of the Byurakan Astrophysical Observatory recently watched as a low luminosity star suddenly burst to life in an extraordinarily short amount of time — becoming 15 times brighter in less than three minutes.

Star WX UMa, which is relatively close-by in the Ursa-major constellation, is about 15.6 light-years from Earth and is part of a binary system. It’s a flare star — a normally subdued low luminosity object that occassionally and unpredicably boosts its brightness and heat in a matter of seconds. But it’s an effect that doesn’t last long. The stars return back to their normal state in about 10 minutes.

Fascinatingly, the effect is so dramatic that the classification of the star literally changes within a few seconds. In this case, WX UMa temporarily transformed from spectral type M to B. Its temperature went from about 2,800 kelvin (K) to six or seven times that — somewhere between 10,000 to 33,000 K.

These flares happen when instability within the plasma of the star causes turbulence in its magnetic field.

“A magnetic reconnection then occurs, a conversion of energy from the magnetic field into kinetic energy, in order to recover the stability of the flow, much like what happens in an electric discharge,” said a researcher when speaking to SINC. This kinetic energy transforms into thermal energy in the upper layers of the atmosphere and the star’s corona, driving up its temperature and brightness.”

Read the entire study at Astrophysics: Spectral observations of flare stars in the neighborhood of the sun.

deconversionmovement: He Helped Discover Evolution, And Then...

Mon, 17 Jun 2013 16:43:19 -0400

deconversionmovement:

He Helped Discover Evolution, And Then Became Extinct

Ask most folks who came up with the theory of evolution, and they’ll tell you it was Charles Darwin.

In fact, Alfred Russel Wallace, another British naturalist, was a co-discoverer of the theory — though Darwin has gotten most of the credit. Wallace died 100 years ago this day.

Continue Reading

spaceplasma: The Whirlpool Galaxy Like You’ve Never Seen it...

Mon, 17 Jun 2013 15:09:01 -0400

In an interferometer, each pair of antennas makes a set of interference fringes on the sky which are proportional to the resolution of the telescope

spaceplasma:

The Whirlpool Galaxy Like You’ve Never Seen it Before

Where do we come from? This is the sort of big question that keeps people up at night, and NASA funded. If you are a star, however, the answer is easy: you come from a big cloud of gas. As astronomers, if we want to understand what controls properties of stars — what makes them big, small, clustered, or isolated– we can start by looking at the gas that will make them.

This paper presents a detailed study of the gas in M51, the Whirlpool galaxy. This system is actually two galaxies, but this paper focuses on the larger, main spiral (NGC 5194) in this interacting pair. This galaxy is relatively close by (20 million light years away), massive (~150 billion solar masses), and quite well-studied: astronomers have looked at it in wavelengths from radio to near-infrared, optical and ultraviolet. The combined resolution and sensitivity of these new millimeter observations (the J=1-0 rotational transition of the carbon monoxide molecule) allow the authors to detect for the first time individual molecular clouds in this galaxy, the objects from which stars and star clusters are born. Below is an image of M51 from this study showing the gas surface density (the amount of gas along our line of sight) from small amounts (dark blue) to large amounts (bright pink), all representing the fuel required to make the next generation of stars in this galaxy.

So what does it take to make an image like this? ALMA? Not quite. M51, with a declination of +47 degrees, is a galaxy that ALMA (the Atacama Large Millimeter Array, located in Chile at a latitude of 23 degrees South) will find very difficult to observe. Instead, the authors used the Plateau de Bure Interferometer (PdBI) and the IRAM 30m radio telescope to detect gas clouds as small as 40 parsecs across. The image above is a mosaic combining 60 pointings of PdBI with IRAM observations over the same region. But isn’t one telescope enough for the job of observing M51? Why take the time to observe it twice?

The answer is that interferometers (arrays of two or more telescopes which work together to act like a telescope with a diameter equal to the separation between antennas) by themselves have a big problem for big objects like M51. Although interferometers give us the advantage of higher resolution, that is not whole story– not only does the antenna separation determine the resolution, it also sets the size scales that you are sensitive to, acting like a high-pass filter for spatial frequencies. As shown in the figure below, a pair of antennas in an interferometer resolve ‘fringes‘ on the sky representing the resolution of that antenna pair (a function of the frequency of the observations and the spacing of the antennas). Different spacings and orientations from the combinations of many antenna-pair fringes contribute to making your beam– the tiny white dot in the bottom left corner of the above image, and the interferometric equivalent of the point-spread function (PSF). The problem is that flux from structures larger than the largest fringe that goes into making this beam will be lost. Since the shortest antenna spacing yields the largest fringe, and the antenna spacing cannot be smaller than the size of the telescope (get too close and the antennas will start bumping into and blocking each other), there is a maximum size scale that you can detect flux from.

How can we get that flux back? Use a single dish telescope! These telescopes are sensitive to the flux on all size scales larger than the resolution of their dish. By combining the data from an interferometer with single dish data, you can recover all of the flux from an object, and still observe it at high resolution. This synergy is why the most effective radio and millimeter interferometers all have a single-dish buddy: the Very Large Array (VLA) has the Green Bank Telescope (GBT), the PdBI (which took these images) has IRAM, and ALMA will have both a compact array and several ‘total power’ single dishes.

So now that you have a high-resolution picture of almost all of the gas clouds in M51, what do you do with it? This paper focuses on comparing (correlating) the location and amount of this gas with other tracers of galaxy properties. This includes tracers of different phases of the interstellar medium (the ISM, or gas in a galaxy at all temperatures, from plasma to neutral to molecular), tracers of star formation, and tracers of the existing stellar populations.

The PdBI Arcsecond Whirlpool Survey (PAWS). I. A Cloud-Scale/Multi-Wavelength View of the Interstellar Medium in a Grand-Design Spiral Galaxy →

sagansense: The Curious Channel 37 — Must-see TV For Radio...

Mon, 17 Jun 2013 13:34:52 -0400

sagansense:

The Curious Channel 37 — Must-see TV For Radio Astronomy

Thanks to Channel 37, radio astronomers keep tabs on everything from the Sun to pulsars to the lonely spaces between the stars. This particular frequency, squarely in the middle of the UHF TV broadcast band, has been reserved for radio astronomy since 1963, when astronomers successfully lobbied the FCC to keep it TV-free.

Back then UHF TV stations were few and far between. Now there are hundreds, and I’m sure a few would love to soak up that last sliver of spectrum. Sorry Charley, the moratorium is still in effect to this day. Not only that, but it’s observed in most countries across the world.

So what’s so important about Channel 37? Well, it’s smack in the middle of two other important bands already allocated to radio astronomy – 410 Megahertz (MHz) and 1.4 Gigahertz (Gz). Without it, radio astronomers would lose a key window in an otherwise continuous radio view of the sky. Imagine a 3-panel bay window with the middle pane painted black. Who wants THAT?

Channel 37 occupies a band spanning from 608-614 MHz. A word about Hertz. Radio waves are a form of light just like the colors we see in the rainbow or the X-rays doctors use to probe our bones. Only difference is, our eyes aren’t sensitive to them. But we can build instruments like X-ray machines and radio telescopes to “see” them for us.

Every color of light has a characteristic wavelength and frequency. Wavelength is the distance between successive crests in a light wave which you can visualize as a wave moving across a pond. Waves of visible light range from one-millionth to one-billionth of a meter, comparable to the size of a virus or DNA molecule.

X-rays crests are jammed together even more tightly – one X-ray is only as big as an small atom. Radio waves fill out the opposite end of the spectrum with wavelengths ranging from baseball-sized to more than 600 miles (1000 km) long.

The frequency of a light wave is measured by how many crests pass a given point over a given time. If only one crest passes that point every second, the light beam has a frequency of 1 cycle per second or 1 Hertz. Blue light has a wavelength of 462 billionths of a meter and frequency of 645 trillion Hertz (645 Terahertz).

The higher the frequency, the greater the energy the light carries. X-rays have frequencies starting around 30 quadrillion Hertz (30 petahertz or 30 PHz), enough juice to damage body cells if you get too much exposure. Even ultraviolet light has power to burn skin as many of us who’ve spent time outdoors in summer without sunscreen are aware.

Radio waves are the gentle giants of the electromagnetic spectrum. Their enormous wavelengths mean low frequencies. Channel 37 radio waves have more modest frequencies of around 600 million Hertz (MHz), while the longest radio waves deliver crests almost twice the width of Lake Superior at a rate of 3 to 300 Hertz.

If Channel 37 were ever lost to TV, the gap would mean a loss of information about the distribution of cosmic rays in the Milky Way galaxy and rapidly rotating stars called pulsars created in the wake of supernovae. Closer to home, observations in the 608-614 MHz band allow astronomers track bursts of radio energy produced by particles blasted out by solar flares traveling through the sun’s outer atmosphere. Some of these can have powerful effects on Earth. No wonder astronomers want to keep this slice of the electromagnetic spectrum quiet. For more details on how useful this sliver is to radio astronomy, click HERE.

Just as optical astronomers seek the darkest sites for their telescopes to probe the most remote corners of the universe, so too does radio astronomy need slices of silence to listen to the faintest whispers of the cosmos.

image 1: The Very Large Array, one of the world’s premier astronomical radio observatories, consists of 27 radio antennas in a Y-shaped configuration 50 miles west of Socorro, New Mexico. Each antenna is 82 feet (25 m) in diameter. The data from the antennas is combined electronically to give the resolution of an antenna 22 miles (36 km) across. credit: NRAO/AUI and NRAO

image 2: Channel 37, a slice of the radio spectrum from 608 and 614 Megahertz (MHz) reserved for radio astronomy, sits in the middle of the UHF TV band. Click to see the full spectrum. credit: US Dept. of Commerce

image 3: The visible colors, infrared, radio, X-rays and gamma rays are all forms of light and comprise the electromagnetic spectrum. Here you can compare their wavelengths with familiar objects and see how their frequencies (bottom numbers) increase with decreasing wavelength. credit: ESA

image 4: Diagram showing what how Earth’s atmosphere allows visible light, a portion of infrared and radio light to reach the ground from outer space but filters shorter-wavelength, more dangerous forms of light like X-rays and gamma rays. To study the cosmos in these varieties of light, orbiting telescopes are required.

image 5: If our eyes could see radio light, this is what the sky would look like. What appear to be stars are actually distant galaxies glowing brightly with energy radiated as matter gets sucked down black holes in the cores. The wispy arcs and shells are the remnants of exploding supernovae. Since air molecules don’t scatter radio waves like they do visible light to create a blue sky, the sky would be dark even on a sunny day. credit: National Science Foundation

image 6: The sun as it would look in the radio portion of the spectrum at a frequency of 1.4 gigahertz (GHz). credit: National Radio Astronomy Observatory (NRAO/AUI)

Stay Curious! Watch: First Contact: Carl Sagan On Radio Astronomy

sci-fact: It is frequently pointed out that the magnetic...

Sun, 16 Jun 2013 21:26:16 -0400

sci-fact:

It is frequently pointed out that the magnetic north pole lies slightly outside the geographic North Pole. This is not technically correct. In fact, the opposite is true. The Earth’s magnetic south pole lies just outside the geographic North Pole. In geography, North is defined by the direction that attracts the north end of a compass, but in physics, the north end of any magnet will always be pulled toward the southern direction of an external magnetic field. What this means is that the magnetic pole that lies in what we call the Northern Hemisphere is actually a magnetic south pole. In precise scientific terms, the “north magnetic pole” and the “magnetic north pole” are exact opposites. Thankfully, these needlessly confusing semantics are usually ignored in favor of the colloquial understanding.

yaleuniversity: How do new arteries form after heart attacks,...

Sun, 16 Jun 2013 19:51:46 -0400

yaleuniversity:

How do new arteries form after heart attacks, strokes and other acute illnesses?

Scientific collaborators from Yale School of Medicine and University College London (UCL) might have the answer. Learn more →

alaskamuseum: SIZING ALASKA’S MASKED SHREWS - Lathrop High...

Sun, 16 Jun 2013 18:17:43 -0400

alaskamuseum:

SIZING ALASKA’S MASKED SHREWS - Lathrop High School Senior Kelly May is headed to the National Junior Science & Humanities Symposium in Ohio this month with a research project refuting an earlier study on the effects of climate change on Alaska’s shrews. For this year’s Alaska Statewide High School Science Symposium (ASHSSS), May repeated a study published in 2005 using masked shrew specimens housed at the University of Alaska Museum of the North.

The original study, which concluded that shrews in Alaska are getting larger, was based entirely on data downloaded from the museum’s online database. The authors were not able to inspect each specimen. May believed that not accounting for age in the original research may have biased the results, so he tracked down each of the 650 specimens used in the original study.

Each shrew species has a unique tooth pattern. Since Alaska’s shrews can be difficult to identify, May first confirmed the specimens were the correct species (Sorex cinereus). Determining the age involved looking at the degree of wear on their teeth. Shrews do not hibernate and are active year round but they rarely live more than 15 months. Adults that survive a winter show significant tooth wear, while shrews born in the spring do not.

May learned that young shrews are significantly smaller than overwintered adults and that overwintered females are bigger than overwintered males. In contrast to previously published claims, this means that age and sex both need to be accounted for in studies of body size in shrews, according to the museum’s curator of mammals, Link Olson.

By analyzing juvenile and adult specimens separately and accounting for sex, May found that individual shrews are actually getting smaller but that more are surviving the winter, meaning that the proportion of (larger-bodied) adults in a given population is increasing. So although the two studies reached seemingly similar conclusions, May’s results shed new light on the underlying mechanism: shrews aren’t growing to a larger body size, they’re just surviving winters better.

In June, May will travel to Philadelphia to present his research at the annual meeting of the American Society of Mammalogists. May plans to attend UAF in the fall.

What Happens To Women When They’re Denied Abortions? A...

Sun, 16 Jun 2013 17:43:21 -0400

What Happens To Women When They’re Denied Abortions?

A first-of-its-kind study tracks the health of women who are denied abortions.

[Image via The New York Times.]

“Plenty of research has examined how getting an abortion affects women’s mental health. (In short,it doesn’t, though individual circumstances vary enough that universal statements about women’s reactions can be misleading.)

But what about those who want an abortion, but can’t get one? Like S., a woman the New York Times Magazine interviewed. S. was 24 when she first found she was pregnant and decided to get an abortion. Click the link to read about her attempts to get the procedure, including one unwitting visit to a clinic where a nurse gave her an ultrasound and told her, “Look! Your baby is smiling at you.”

Ultimately, as is the case with most women who are turned away from abortion clinics, S.’s 20-week-old pregnancy was too far along. The opening sequence ends with S. set on a certain road:

She was out of gas money, hadn’t eaten a decent meal in weeks and resigned herself to the fact that, no matter what she wanted or how it would affect her life, she was going to have a baby.

Strangely, researchers have never followed American women who, like S., couldn’t get the abortions they wanted, the New York Times Magazine reported. That’s about to change. The magazine reported on a study, led by Diana Greene Foster, a demographer and professor of ob-gyn at the University of California, San Francisco. Foster’s study is the first to track American women like this over a longer period of time—and the first in the world to compare those women with peers who successfully received abortions.

Although her study is ongoing, Foster already has some answers. Compared to their peers who received abortions, women who can’t get the abortions they want have poorer health and are more likely to live in poverty two years on, even though they qualified for government assistance programs as new moms. Meanwhile, everybody in the study, whether they got abortions or not, generally had the same levels of depression and anxiety.

With time, Foster’s study will be able to assess how well mothers like S. bond with their children, how well those babies fare, and how well their mothers fare financially in the long term.

Whether Foster’s results will budge the beliefs of those on either side of the abortion debate remains to be seen. There’s nothing in the study to address the concerns of people who find abortion immoral—in fact, that’s a question science simply can’t answer.” [via POPSCI.]

Read the full New York Times Magazine article here.