![Quasar
In the image:Artist’s rendering of ULAS J1120+0641, a very distant quasar powered by a black hole with a mass two billion times that of the Sun.[1] Credit: ESO/M. Kornmesser
A quasi-stellar radio source (“quasar”) is a very energetic and distant active galactic nucleus. Quasars are extremely luminous and were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars, rather than extended sources similar togalaxies.
While the nature of these objects was controversial until as recently as the early 1980s, there is now a scientific consensus that a quasar is a compact region in the center of a massive galaxy surrounding its central supermassive black hole. Its size is 10–10,000 times the Schwarzschild radius of the black hole. The quasar is powered by an accretion disc around the black hole.](http://25.media.tumblr.com/tumblr_m3a8pnJ2CA1qbkzabo1_500.jpg)
Quasar
In the image:Artist’s rendering of ULAS J1120+0641, a very distant quasar powered by a black hole with a mass two billion times that of the Sun.[1] Credit: ESO/M. Kornmesser
A quasi-stellar radio source (“quasar”) is a very energetic and distant active galactic nucleus. Quasars are extremely luminous and were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars, rather than extended sources similar togalaxies.
While the nature of these objects was controversial until as recently as the early 1980s, there is now a scientific consensus that a quasar is a compact region in the center of a massive galaxy surrounding its central supermassive black hole. Its size is 10–10,000 times the Schwarzschild radius of the black hole. The quasar is powered by an accretion disc around the black hole.
Michael Faraday
Michael Faraday (1791–1867) delivering the 1856 Christmas Lecture at the Royal Institution
The Cognitive Benefits Of Chewing Gum
Why do people chew gum?
If an anthropologist from Mars ever visited a typical supermarket, they’d be confounded by those shelves near the checkout aisle that display dozens of flavored gum options. Chewing without eating seems like such a ridiculous habit, the oral equivalent of running on a treadmill. And yet, people have been chewing gum for thousands of years, ever since the ancient Greeks began popping wads of mastic tree resin in their mouth to sweeten the breath. Socrates probably chewed gum.
It turns out there’s an excellent rationale for this long-standing cultural habit: Gum is an effective booster of mental performance, conferring all sorts of benefits without any side effects.
While previous studies achieved similar results — chewing gum is often a better test aid than caffeine — this latest research investigated the time course of the gum advantage. It turns out to be rather short lived, as gum chewers only showed an increase in performance during the first 20 minutes of testing. After that, they performed identically to non-chewers.
What’s responsible for this mental boost? Nobody really knows. It doesn’t appear to depend on glucose, since sugar-free gum generated the same benefits. Instead, the researchers propose that gum enhances performance due to “mastication-induced arousal.” The act of chewing, in other words, wakes us up, ensuring that we are fully focused on the task at hand. Unfortunately, this boost is fleeting. The takeaway of this research is straightforward: When taking a test, save the gum for the hardest part, or for those questions when you feel your focus flagging. The gum will help you concentrate, but the help won’t last long.
Last month, scientists at Coventry University found that people chewing mint gum showed a dramatic decrease in feelings of sleepiness. The subjects also looked less exhausted when assessed with the Pupillographic Sleepiness Test (PST), which uses the oscillations of the pupils as a metric of tiredness. When we chew gum, we gain alertness and attention, but without the jitters.
And then there’s this paper, from a researcher at Cardiff University. 133 volunteers were given cognitive tests with and without chewing gum. After each testing session, the volunteers rated their mood and underwent a number of physiological measurements, including heart rate and salivary cortisol levels. As expected, gum chewers were more attentive than non-chewers, with elevated heart rates and cortisol levels. They also had much faster reaction times, especially on more difficult reaction tests. They even appeared to be in a better mood.
A recent review of the gum-chewing literature summarizes the science: “Gum appears to be a functional food with function but no food.”
Photo: Flickr/world of jan
Mitosis
Prophase: The two round objects above the nucleus are the centrosomes. The chromatin is condensing into chromosomes.
Prometaphase: The nuclear membrane disintegrates, and microtubules have invaded the nuclear space. These microtubules can attach to kinetochores or they can interact with opposing microtubules.
Metaphase: The chromosomes align at the metaphase plate.
Anaphase: The chromosomes split and the kinetochore microtubules shorten.
Telophase: The decondensing chromosomes are surrounded by nuclear membranes. Cytokinesis has already begun; the pinched area is known as the cleavage furrow.
Earth’s First
1. First Full-View Photo of Earth
Photograph courtesy NASA Johnson Space Center
This famous “Blue Marble” shot represents the first photograph in which Earth is in full view. The picture was taken on December 7, 1972, as the Apollo 17 crew left Earth’s orbit for the moon. With the sun at their backs, the crew had a perfectly lit view of the blue planet.
2. New Blue Marble
Image courtesy Norman Kuring, Suomi NPP/NASA/NOAA
North and Central America star in a new “blue marble” picture of Earth. The high-resolution composite was made with data collected January 4 by a NASA satellite.
The National Polar-orbiting Operational Environmental Satellite System Preparatory Project, or NPP, launched on October 28, 2011, to become NASA’s next-generation Earth-monitoring probe. The satellite was designed to help improve short-term weather forecasts and increase our understanding of long-term climate change.
The 2012 blue marble was released this week to mark the announcement of the probe’s new name—Suomi NPP—in honor of the late Verner E. Suomi of the University of Wisconsin, a pioneer in satellite meteorology.
No one can escape friction, not even in a vacuum.
On earth, we’re slowed down by the muck of the everyday world. Matter slows us down, rubbing against us and taking away our speed and power. Gravel, air, even slip-n-slides, exert some friction on us. This frictional force runs counter to our motion, and it can’t be escaped anywhere on earth. Eventually, inevitably, it will slow us to a stop.
Ah, but in space all the rules are different. In a vacuum, with no matter to rub up against like a strangers on the bus, we could move forever. If we started in a spin, we’d never stop unless we had a collision with some kind of asteroid. It turns out, that even in the vacuum of space, we’d get dragged back. The vacuum isn’t as entirely devoid of matter as most people make it out to be. It’s only devoid of permanent matter. In a vacuum, tiny, temporary, particles pop in and out of existence all the time.
These particles, at first glance, shouldn’t drag down a spinning object. Since they are popping up on all sides, hitting it from every direction, their cumulative effect should be zero. At least two physicists at the Spanish National Research Council say this isn’t the case. If a particle hits a spinning object in the direction of its spin, a part of its momentum may be transfered to the object. If, however, a particle hits a spinning object counter to its direction, more of its momentum will be transferred to the spinning object. If particles moving counter to the object’s motion hit with more force than particles moving with the object, the object will eventually stop moving. Not even in space is motion preservered.
Via New Scientist.
Three Smart Things About Lasers
- The power of the first laser was measured in Gillettes. In 1960, before there was a precise scientific measurement, Theodore Maiman defined the strength of a beam by the number of Gillette razor blades it could cut through. A Gillette equals about 1.5 joules; today’s strongest laser produces about 1.8 million joules, or 1.2 million Gillettes.
- NASA will use them for hi-def broadcasts. We currently send messages through space with radio waves, which is like using dialup—it takes 90 minutes to beam a stinkin’ photo down from Mars. NASA plans to have a laser-based system ready for testing by 2016. If it works, astronauts won’t need to worry about missing an episode of Community while on the Red Planet.
- Generally, you shouldn’t look to sci-fi for a vision of future technology. But a lot of the laser tech in Star Wars is actually feasible: Scientists seem to be making progress toward real, functioning tractor beams, laser weapons, and 3-D holograms. All well and good, but where’s my damn lightsaber?
Source: Transportation Security Administration
Image by Wiki
Light’s in
98% water.
Developing Frog
Dr. Mike Klymkowsky, MCD Biology, University of Colorado — Boulder
![Meet 55 Cancri e — the “oozing” exoplanet
When you combine a compound like water with intense heat, said water evaporates. No mystery there. But when you throw extreme pressure into the mix, something funny happens. The compound can actually achieve what is called a “supercritical” fluid state, taking on properties of liquid and gas alike.
Now, astronomers at MIT have revealed that exoplanet 55 Cancri e — once thought to be a dry, rocky world — may be literally oozing with supercritical fluids.
The discovery is a strange one, to be sure. Supercritical fluids, which are commonly described as “liquid-like gasses” are pretty wacky, and posses some totally bizarre properties (there is, for example, no surface tension in a supercritical fluid… yeah, wrap your head around that, why don’t you). But this drastic revision in our understanding of the planet’s surface characteristics also calls attention the incredibly mysterious nature of exoplanets in general.
55 Cancri e (an artist’s rendition is pictured up top, situated beside Earth) is an old-school exoplanetary discovery; identified all the way back in 2004, 55 Cancri e belongs to the relatively small collection of extrasolar planets discovered prior to the planet-hunting days of NASA’s highly productive Kepler telescope. That means we’ve had more time than usual to get familiar with it.
And we’ve learned quite a bit over the course of eight years. Since its initial discovery, several characteristics of the Neptune-Mass planet have come under revision. Its orbital period, for example (the time it takes to make one trip around its star) was changed from 2.8 days to less than 18 hours. Once thought to be the densest known planet in the galaxy, another team of astronomers soon showed that this was not the case.
Now, using data from NASA’s Spitzer space telescope, atmospheric scientist Brice-Olivier Demory and his colleagues at MIT may have the proof they need (their findings are still in the peer-review stage) for one of the most mysterious revisions to date; “[The team’s] observations,” writes NASA’s Tony Phillips, “suggest that 55 Cancri e may be wetter and weirder than anyone imagined.” With newly identified exoplanets tallying up faster than ever before, there’s no telling what strange, wonderful worlds await our discovery (and rediscovery) here in our galaxy.
Via NASA. Top image via Wikimedia Commons](http://24.media.tumblr.com/tumblr_lxybx0NxYF1qbkzabo1_500.jpg)
Meet 55 Cancri e — the “oozing” exoplanet
When you combine a compound like water with intense heat, said water evaporates. No mystery there. But when you throw extreme pressure into the mix, something funny happens. The compound can actually achieve what is called a “supercritical” fluid state, taking on properties of liquid and gas alike.
Now, astronomers at MIT have revealed that exoplanet 55 Cancri e — once thought to be a dry, rocky world — may be literally oozing with supercritical fluids.
The discovery is a strange one, to be sure. Supercritical fluids, which are commonly described as “liquid-like gasses” are pretty wacky, and posses some totally bizarre properties (there is, for example, no surface tension in a supercritical fluid… yeah, wrap your head around that, why don’t you). But this drastic revision in our understanding of the planet’s surface characteristics also calls attention the incredibly mysterious nature of exoplanets in general.
55 Cancri e (an artist’s rendition is pictured up top, situated beside Earth) is an old-school exoplanetary discovery; identified all the way back in 2004, 55 Cancri e belongs to the relatively small collection of extrasolar planets discovered prior to the planet-hunting days of NASA’s highly productive Kepler telescope. That means we’ve had more time than usual to get familiar with it.
And we’ve learned quite a bit over the course of eight years. Since its initial discovery, several characteristics of the Neptune-Mass planet have come under revision. Its orbital period, for example (the time it takes to make one trip around its star) was changed from 2.8 days to less than 18 hours. Once thought to be the densest known planet in the galaxy, another team of astronomers soon showed that this was not the case.
Now, using data from NASA’s Spitzer space telescope, atmospheric scientist Brice-Olivier Demory and his colleagues at MIT may have the proof they need (their findings are still in the peer-review stage) for one of the most mysterious revisions to date; “[The team’s] observations,” writes NASA’s Tony Phillips, “suggest that 55 Cancri e may be wetter and weirder than anyone imagined.” With newly identified exoplanets tallying up faster than ever before, there’s no telling what strange, wonderful worlds await our discovery (and rediscovery) here in our galaxy.
Via NASA. Top image via Wikimedia Commons
