Dark Energy & Dark Matter via Chandra X-ray Observatory (Illustration: NASA/CXC/M.Weiss)
“The two largest pieces of the Universe that we know the least about, yet nothing less than the ultimate fate of the Universe will be determined by them.”
(via astrotastic)
Source: thescienceofreality
Science and Space Posters by Ron Guyatt
Part of a series for spacevidcast.com to help inspire and spread the Good Word of Science! Prints available at etsy.
(via itsfullofstars)
Source: ianbrooks
Maxwell’s Equations in Differential and Integral form, probably the extreme expression of mathematical beauty of Physics.
Source (The Physics Education Research group at the University of Colorado Boulder)
The mauve stinger produces bioluminescent light shows, which are often admired from passing boats, but it also has a reputation as a ferocious stinger. As well as having eight stinging tentacles, this jellyfish is covered in tiny red spots that are bundles of stinging cells. The sting is painful but not dangerous. The mauve stinger glows by producing luminous mucus from surface cells when it is knocked or disturbed by waves. Hanging down from the underside of the mushroom-shaped bell are four long, frilly mouth lobes, which are sometimes called oral arms. These also have stinging cells that paralyze and entangle small planktonic animals. Sticky mucus holds the prey, which is then passed up grooves in the arms and into the mouth.
Unlike most jellyfish, the life cycle of the mauve stinger does not involve a fixed stage. Eggs and sperm are shed into the water, where the eggs are fertilized and develop into tiny, oval planula larvae covered in hairlike cilia. The planula larva changes directly into a tiny, lobed, saucer-shaped medusa called an ephyra, which gradually develops into an adult mauve stinger.
via: Oceana
(via we-are-star-stuff)
Source: underthevastblueseas
When birds ingest the chili pepper seeds, it goes right through their digestion tract and is passed out. Thus, they help in germination of the seeds.
But, mammals do not do this. Their teeth crush the seeds long before it can pass through their stomach. This prevents germination of the seeds and is a big no-no for the chili peppers.
So, they have developed a cunning strategy to combat this. You would probably know that chili pepper contain a molecule called capsaicin, which is present in the placental tissue around the seeds. This is the molecule that gives us that hot feeling when we eat peppers.
Capsaicin acts by binding to the TRPV1 heat receptor. But, the important point is that, it does so ONLY in mammals and not in birds. Thus, mammals feel a very hot sensation when eating chili-peppers and will generally avoid it after that. But, birds do not feel a thing. Thus, capsaicin stops mammals from destroying their seeds, while still allowing birds to germinate them.
So, natural selection has selected those chili peppers that produce more capsaicin, so they can better protect themselves. This is a beautiful demonstration of Darwin’s stuff.
Of course, mother nature did not count on us Homo sapiens, who like to torture themselves with heat !
Source - http://www.nature.com/nature/journal/v412/n6845/full/412403a0.html via http://en.wikipedia.org/wiki/Capsaicin#cite_note-20
You’re gonna want to click this.
Trust me.
That’s far. (Dunno if it works on mobile)
(via we-are-star-stuff)
Source: jtotheizzoe
These vegetated surfaces don’t just look pretty. They have other benefits as well, including cooling city blocks, reducing loud noises, and improving a building’s energy efficiency.What’s more, a recent modeling study shows that green walls can potentially reduce large amounts of air pollution in what’s called a “street canyon,” or the corridor between tall buildings.
For the study, Thomas Pugh, a biogeochemist at the Karlsruhe Institute of Technology in Germany, and his colleagues created a computer model of a green wall with generic vegetation in a Western European city. Then they recorded chemical reactions based on a variety of factors, such as wind speed and building placement.
The simulation revealed a clear pattern: A green wall in a street canyon trapped or absorbed large amounts of nitrogen dioxide and particulate matter—both pollutants harmful to people, said Pugh. Compared with reducing emissions from cars, little attention has been focused on how to trap or take up more of the pollutants, added Pugh, whose study was published last year in the journal Environmental Science & Technology.
That’s why the green-wall study is “putting forward an alternative solution that might allow [governments] to improve air quality in these problem hot spots,” he said.Compared with reducing emissions from cars, little attention has been focused on how to trap or take up more of the pollutants, added Pugh, whose study was published last year in the journal Environmental Science & Technology.
That’s why the green-wall study is “putting forward an alternative solution that might allow [governments] to improve air quality in these problem hot spots,” he said.This should seriously be done… everywhere. Well not everywhere. But LOTS of places.
Exceptionally rad. I’d love to see this being done in my city.
(via sleepingamajority)
Source: National Geographic
Singing Sand Dunes
But there is a marvellous thing related of this Desert, which is that when travellers are on the move by night, and one of them chances to lag behind or to fall asleep or the like, when he tries to gain his company again he will hear spirits talking, and will suppose them to be his comrades. Sometimes the spirits will call him by name; and thus shall a traveller ofttimes be led astray so that he never finds his party. And in this way many have perished. [Sometimes the stray travellers will hear as it were the tramp and hum of a great cavalcade of people away from the real line of road, and taking this to be their own company they will follow the sound; and when day breaks they find that a cheat has been put on them and that they are in an ill plight. Even in the day-time one hears those spirits talking. And sometimes you shall hear the sound of a variety of musical instruments, and still more commonly the sound of drums.
Travellers in the desert have long known that shifting sand can make an eerie noise, ranging from a bass boom to a baritone bark and a soprano whistle. The sound occurs when the ridge of a sand dune builds up and eventually topples. This shear effect causes a mini-avalanche of sand in which millions of grains rub against each other as they fall. But different materials and different conditions make different songs.Lab experiments show that synchronicity plays a vital role. Put simply, enough grains have to be flowing at the same rate in order to create and amplify the oscillation. In turn, the factors behind synchronicity are wind speed, humidity, the size of the sand grain and the smoothness of its coating, too.
Much of the scientific fascination surrounding booming dunes stems from the fact that their properties are so hard to pin down. Booming doesn’t occur on all desert dunes. And on those that do boom, the phenomenon doesn’t occur throughout the entire year or everywhere across the dune. The frequency can vary too – from roughly 65 to 120 Hertz – while the volume can reach 110 decibels — just 20 dB short of the pain threshold.
The sound is not related to the type of dune or its location. And while it’s mostly at a pitch akin to the drone of a low-flying aeroplane, its timbre ranges from a rough brass-like clamour of Oman’s dunes, on the Arabian Peninsula, to the pure vocal sound of Morocco’s. Scientists agree that the noise only arises from a dune’s upper slip face (the leeward side), never from the shallow, windward face. What’s more, booming only happens when conditions are hot and dry and when the sand grains are clean, round and polished.
Despite these clues, the most fundamental question remains: what does make the dunes sing?
Sources: [x] [x] [x]
Image: [x]
Audio: Physicist Simon Dagois-Bohy and his fellow researchers at Paris Diderot University in France recorded two different dunes: one near Al-Askharah, a coastal town in southeastern Oman, and one near Tarfaya, a port town in southwestern Morocco.
(via we-are-star-stuff)
Source: science-junkie
After finding Mars was habitable, Curiosity keeps on roving
NASA recounts the 7-month history of its latest Mars rover.
(via itsfullofstars)
Source: mothernaturenetwork
Comet, Not Asteroid May Have Wiped Out Dinosaurs Study Suggests
The rocky object that wiped out the dinosaurs 65 million years ago may have been a comet, rather than an asteroid, scientists say.
The 112-mile (180 kilometers) Chicxulub crater in Mexico was made by the impact that caused the extinction of dinosaurs and about 70 percent of all species on Earth, many scientists believe. A new study suggests the crater was probably blasted out by a faster, smaller object than previously thought, according to research presented this week at the 44th Lunar and Planetary Science Conference in The Woodlands, Texas.
Evidence of the space rock’s impact comes from a worldwide layer of sediments containing high levels of the element iridium, dubbed the Cretaceous-Paleogene (K-Pg) boundary, which could not have occurred on Earth naturally.
The new research suggests the often-cited iridium values are incorrect, however. The scientists compared these values with levels of osmium, another element delivered by the impact.
Their calculations suggested the space rock generated less debris than previously thought, implying the space rock was a smaller object. In order for the smaller rock to have created the giant Chicxulub crater, it had to have been going exceedingly fast, the researchers concluded.
“How do we get something that has enough energy to generate that size of crater, but has much less rocky material? That brings us to comets,” study author Jason Moore, a paleoecologist at Dartmouth College in New Hampshire, told BBC News.
[Meteor Crater: Experience an Ancient Impact]
Images: Don Davis/David Hardy
(via we-are-star-stuff)
Source: electricspacekoolaid
A Science blog run by Nathan (iamvishnu).
Most posts are about physics and astronomy, but other areas of science are covered as well.
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