This image hurts my brain more than the original debate ever did. Brains are dumb.
I am not going to tag the name of the bird, because I’m pretty sure I would get tagged as NSFW if I did, but I assure you their beaks are getting longer and it’s probably because of the UK’s obsession with bird feeders.
A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter. Galaxies range in size from dwarfs with just a few hundred million (108) stars to giants with one hundred trillion (1014) stars, each orbiting its galaxy’s center of mass.
Galaxies come in three main types: ellipticals, spirals, and irregulars. A slightly more extensive description of galaxy types based on their appearance is given by the Hubble sequence.
Since the Hubble sequence is entirely based upon visual morphological type (shape), it may miss certain important characteristics of galaxies such as star formation rate in starburst galaxies and activity in the cores of active galaxies.
The Hubble classification system rates elliptical galaxies on the basis of their ellipticity, ranging from E0, being nearly spherical, up to E7, which is highly elongated. These galaxies have an ellipsoidal profile, giving them an elliptical appearance regardless of the viewing angle. Their appearance shows little structure and they typically have relatively little interstellar matter. Consequently, these galaxies also have a low portion of open clusters and a reduced rate of new star formation. Instead they are dominated by generally older, more evolved stars that are orbiting the common center of gravity in random directions.
Spiral galaxies resemble spiraling pinwheels. Though the stars and other visible material contained in such a galaxy lie mostly on a plane, the majority of mass in spiral galaxies exists in a roughly spherical halo of dark matter that extends beyond the visible component, as demonstrated by the universal rotation curve concept.
Spiral galaxies consist of a rotating disk of stars and interstellar medium, along with a central bulge of generally older stars. Extending outward from the bulge are relatively bright arms. In the Hubble classification scheme, spiral galaxies are listed as type S, followed by a letter (a, b, or c) that indicates the degree of tightness of the spiral arms and the size of the central bulge.
A majority of spiral galaxies, including our own Milky Way galaxy, have a linear, bar-shaped band of stars that extends outward to either side of the core, then merges into the spiral arm structure. In the Hubble classification scheme, these are designated by an SB, followed by a lower-case letter (a, b or c) that indicates the form of the spiral arms (in the same manner as the categorization of normal spiral galaxies).
A ring galaxy is a galaxy with a circle-like appearance. Hoag’s Object, discovered by Art Hoag in 1950, is an example of a ring galaxy. The ring contains many massive, relatively young blue stars, which are extremely bright. The central region contains relatively little luminous matter. Some astronomers believe that ring galaxies are formed when a smaller galaxy passes through the center of a larger galaxy. Because most of a galaxy consists of empty space, this “collision” rarely results in any actual collisions between stars.
A lenticular galaxy (denoted S0) is a type of galaxy intermediate between an elliptical (denoted E) and a spiral galaxy in galaxy morphological classification schemes. They contain large-scale discs but they do not have large-scale spiral arms. Lenticular galaxies are disc galaxies that have used up or lost most of their interstellar matter and therefore have very little ongoing star formation. They may, however, retain significant dust in their disks.
An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure.
Despite the prominence of large elliptical and spiral galaxies, most galaxies in the Universe are dwarf galaxies. These galaxies are relatively small when compared with other galactic formations, being about one hundredth the size of the Milky Way, containing only a few billion stars. Ultra-compact dwarf galaxies have recently been discovered that are only 100 parsecs across.
Interactions between galaxies are relatively frequent, and they can play an important role in galactic evolution. Near misses between galaxies result in warping distortions due to tidal interactions, and may cause some exchange of gas and dust. Collisions occur when two galaxies pass directly through each other and have sufficient relative momentum not to merge.
Stars are created within galaxies from a reserve of cold gas that forms into giant molecular clouds. Some galaxies have been observed to form stars at an exceptional rate, which is known as a starburst. If they continue to do so, then they would consume their reserve of gas in a time span less than the lifespan of the galaxy. Hence starburst activity usually lasts for only about ten million years, a relatively brief period in the history of a galaxy.
A portion of the observable galaxies are classified as active galaxies if the galaxy contains an active galactic nucleus (AGN). A significant portion of the total energy output from the galaxy is emitted by the active galactic nucleus, instead of the stars, dust and interstellar medium of the galaxy.
The standard model for an active galactic nucleus is based upon an accretion disc that forms around a supermassive black hole (SMBH) at the core region of the galaxy. The radiation from an active galactic nucleus results from the gravitational energy of matter as it falls toward the black hole from the disc. In about 10% of these galaxies, a diametrically opposed pair of energetic jets ejects particles from the galaxy core at velocities close to the speed of light. The mechanism for producing these jets is not well understood.
The main known types are: Seyfert galaxies, quasars, Blazars, LINERS and Radio galaxy.
source
images: NASA/ESA, Hubble (via wikipedia)
Redrawing the brain’s motor map
Neuroscientists at Emory have refined a map showing which parts of the brain are activated during head rotation, resolving a decades-old puzzle. Their findings may help in the study of movement disorders affecting the head and neck, such as cervical dystonia and head tremor.
The results were published in Journal of Neuroscience.
In landmark experiments published in the 1940s and 50s, Canadian neurosurgeon Wilder Penfield and colleagues determined which parts of the motor cortex controlled the movements of which parts of the body.
Penfield stimulated the brain with electricity in patients undergoing epilepsy surgery, and used the results to draw a “motor homunculus”: a distorted representation of the human body within the brain. Penfield assigned control of the neck muscles to a region between those that control the fingers and face, a finding inconsistent with some studies that came later.
Using modern functional MRI (magnetic resonance imaging), researchers at Emory University School of Medicine have shown that the neck’s motor control region in the brain is actually between the shoulders and trunk, a location that more closely matches the arrangement of the body itself.
“We can’t be that hard on Penfield, because the number of cases where he was able to study head movement was quite limited, and studying head motion as he did, by applying an electrode directly to the brain, creates some challenges,” says lead author Buz Jinnah, MD, professor of neurology, human genetics and pediatrics at Emory University School of Medicine.
The new location for the neck muscles makes more sense, because it corresponds to a similar map Penfield established of the sense of touch (the somatosensory cortex), Jinnah says.
Participants in brain imaging studies need to keep their heads still to provide accurate data, so volunteers were asked to perform isometric muscle contraction. They attempted to rotate their heads to the left or the right, even though head movement was restricted by foam padding and restraining straps.
First author Cecilia Prudente, a graduate student in neuroscience who is now a postdoctoral associate at the University of Minnesota, developed the isometric head movement task and obtained internal funding that allowed the study to proceed.
She and Jinnah knew that isometric exercises for the wrist activated the same regions of the motor cortex as wrist movements, and used that as a reference point in their study. During brain imaging, they were able to check that particular muscles were being tensed by directly monitoring volunteers’ muscles electronically.
When volunteers contracted their neck muscles, researchers were able to detect activation in other parts of the brain too, such as the cerebellum and the basal ganglia, which are known to be involved in movement control. This comes as no surprise, Jinnah says, since these regions also control movements of the hands and other body parts.
Prudente, Jinnah and colleagues have conducted a similar study with cervical dystonia patients, with the goal of comparing the patterns of brain activation between healthy volunteers and the patients. Cervical dystonia is a painful condition in which the neck muscles contract involuntarily and the head posture is distorted.
“These results may help guide future studies in humans and animals, as well as medical or surgical interventions for cervical dystonia and other disorders involving abnormal head movements,” Prudente says.
Article by Chris Weller, Tech Insider & Business Insider
If you’re ever in a car with Graham, then don’t bother telling him to buckle his seat belt. His body is already designed to withstand high-speed impacts.
Designed by a trauma surgeon, an artist, and a crash investigator, Graham is a hypothetical scenario come to life. Supported by Australia’s Transport Accident Commission, the project is meant to highlight how vulnerable humans are to injury.
Graham, however, is not.
Keep reading
My kid is playing a paper piano. I think I might be more wowed than anyone else in my house.
Besides the nerdy factor of circuit completion and conductivity of graphite… It’s just kind of kickass that a paper piano that I drew can work just like a real one with minimal effort AND my kids can play it way easier than a real piano.
A new species is evolving before scientists’ eyes in the eastern United States.
Wolves faced with a diminishing number of potential mates are lowering their standards and mating with other, similar species, reported The Economist.
The interbreeding began up to 200 years ago, as European settlers pushed into southern Ontario and cleared the animal’s habitat for farming and killed a large number of the wolves that lived there.
That also allowed coyotes to spread from the prairies, and the white farmers brought dogs into the region.
Over time, wolves began mating with their new, genetically similar neighbors.
The resulting offspring — which has been called the eastern coyote or, to some, the “coywolf” — now number in the millions, according to researchers at North Carolina State University.
Interspecies-bred animals are typically less vigorous than their parents, The Economist reported — if the offspring survive at all.
At about 55 pounds, the hybrid animal is about twice as heavy as a standard coyote, and her large jaws, faster legs and muscular body allow her to take down small deer and even hunt moose in packs, and the animal is skilled at hunting in both open terrain and dense woodland.
An analysis of 437 hybrid animals found that coyote DNA dominates her genetic makeup, with about one-tenth of its DNA from dogs, usually larger dogs such as Doberman pinschers and German shepherds, and a quarter from wolves.
The coywolves have spread into some of the nation’s largest cities — including New York, Boston and Washington — using railway corridors.
The interbreeding allows the animal to diversify her diet and eat discarded food, along with rodents and smaller mammals — including cats, which coywolves eat skull and all — and they have evolved to become nocturnal to avoid humans.
The animals are also smart enough to learn to look both ways before crossing roads.
Not all researchers agree the animal is a distinct species, arguing that one species does not interbreed with another — although the hybrid’s existence raises the question of whether wolves and coyotes are distinct species in the first place.
But scientists who have studied the animal say the mixing of genes has been much faster, extensive and transformational than anyone had noticed until fairly recently.
“(This) amazing contemporary evolution story (is) happening right underneath our nose,” said Roland Kays, a researcher at North Carolina State.
Watch this report on coywolves.