Stars are colossal fusion reactors, burning hydrogen into helium. As the nuclei fuse lighter elements into heavier elements, massive amounts of energy are released. A new game sets you the task of nucleosynthesis, building hydrogen into iron, and it’s surprisingly fun.
"The game is a stellar variant of 2048, where you fuse elements together along the reaction pathways that power stars." (Read: you’ll never get another thing done)
Play it here: http://newbrict.github.io/Fe26/
This is wonderfully addictive.
I’m a fan!
Astronomers have discovered a unique triple star system that could reveal gravity’s true nature and resolve difficulties with Einstein’s Theory of General Relativity. The system contains a pulsar with two white dwarfs all packed in a space smaller than Earth’s orbit of the Sun. These unusually close orbits allows precise measurements of gravity. via ScienceAlert/fb
Massive Star Makes Waves
The giant star Zeta Ophiuchi is having a “shocking” effect on the surrounding dust clouds in this infrared image from NASA’s Spitzer Space Telescope. Stellar winds flowing out from this fast-moving star are making ripples in the dust as it approaches, creating a bow shock seen as glowing gossamer threads, which, for this star, are only seen in infrared light.
Zeta Ophiuchi is a young, large and hot star located around 370 light-years away. It dwarfs our own sun in many ways — it is about six times hotter, eight times wider, 20 times more massive, and about 80,000 times as bright. Even at its great distance, it would be one of the brightest stars in the sky were it not largely obscured by foreground dust clouds.
This massive star is travelling at a snappy pace of about 54,000 mph (24 kilometers per second), fast enough to break the sound barrier in the surrounding interstellar material. Because of this motion, it creates a spectacular bow shock ahead of its direction of travel (to the left). The structure is analogous to the ripples that precede the bow of a ship as it moves through the water, or the sonic boom of an airplane hitting supersonic speeds.
“I went to take a starry sky in Uyuni salt lake !”
I understand that the air force has been through budget cuts but damn
i know, they can’t even afford the new Firebolts
3D Printing Cancerous Cells Can be Used to Further Cancer Research
"This is a microscopic photo of a butterfly egg. Most butterflies deposit a cluster of tiny eggs, sometimes hundreds of them, on the underside of a leaf, fastening them there with a glue-like substance. The leaves provide protection—and later, food—for the young caterpillars. Filmmaker Louie Schwartzberg reveals spectacular natural beauty imperceptible to the human eye."
Kepler Telescope Discovers Most Earth-Like Planet Yet: A nearly Earth-size planet orbits in a star’s habitable zone, detected by NASA astronomers.
Red sunshine, seas, and maybe aliens? Scientists analyzing data from NASA’s Kepler Space Telescope today report the closest thing yet to another Earth, a world in a habitable orbit around a red dwarf star some 493 light-years away.
Here’s a short video (with sweet music) showing how molecular docking works. Molecular docking uses computational tools to determine the affinity of a ligand for a target. This is generally done using a crystal structure, or occassionally an NMR structure, of the target protein. Assuming the crystal structure has been determined, it has likely been deposited in the Protein Data Bank, where it can be accessed for free. Once the target structure has been inputted to the docking program and the binding area defined, one can screen large libraries of molecules for target binding affinity. Programs such as AutoDock Vina determine the affinity of a ligand for the target (in kcal/mole) based on favorable and unfavorable thermodynamic interactions. So, a ligand that fits favorably in the binding area and has favorable interactions such as hydrogen bonding, pi-stacking, or van der Waals contacts will give a good binding constant. Meanwhile, a ligand that has steric clashes or unfavorable interactions such as charge repulsions will give a poor binding constant.
Computational screening allows one to test large numbers of molecules in a short period of time, in a much cheaper manner than using biological assays. Although successful binders identified by computational screening won’t necessarily show success in experimental assays, they are often a good starting point, especially for research groups with limited resources.
The first part of the video shows a number of molecules being screened. Once a good lead compound with a favorable binding constant has been identified, it is systematically modified to increase its binding affinity for the target. This is analogous to how medicinal chemists make systematic changes to lead compounds to increase their potency.
The myth that the Earth was flat persisted far longer than it should have. Philosophers and scientists suggested the Earth was round as far back as Pythagoras, or perhaps even further, and Eratosthenes even calculated its circumference with decent accuracy in the second century BC. It went on for centuries more, ultimately culminating in that most basic satisfying piece of evidence: the photos of the Earth as seen from space. Not even the most scientifically illiterate person could now doubt the facts. Earth is a sphere.
But why is the Earth, like all other planets, a sphere? Not to be evasive, but the simplest answer is: because they’re planets. When trying to come up with a mass threshold to differentiate planets from smaller bodies like asteroids, one of the primary rubrics is whether the body is massive enough to hold a spherical shape. So, there’s a giveaway: the answer is related to mass - and the most obvious force related to mass is, of course, gravity.
The reason planets are spherical is because the mass of the whole body creates a gravity well that is theoretically centered on the mass-center of the body itself. An irregularly shaped protoplanet, say with a lobe of heavy material sticking out in one direction, might have its gravitational center pulled away from the physical center of the shape. Over millions and billions of years, though, the strong pull down in all directions evens out those bumps.
The constituents of Earth might seem solid, but they are malleable under so much strain, and can flow like putty. In essence, gravity slowly deforms a planet to turn the gravitational center into the physical center. On a long enough timeline, the slow, even pull down the gravity well compresses a planet down to the most compact distribution around the center - in other words, a sphere.
Asteroids are often very oddly shaped with multiple lobes or jutting arms. This is because they are too small to create enough gravity to compress themselves down into a ball. Compared with the internal forces that hold matter together, gravity is very weak. A body must grow very large to exert enough gravity to overcome those forces. Many comets are much closer to spherical, however, because it takes so much less force to change the shape of ice than of rock.
Five hundred light years away, the fifth planet orbiting a small dim star called Kepler-186 has caught scientists’ eyes as being not only roughly Earth-sized, but also within what’s called the “habitable zone” that could support liquid water on the planet’s surface.
The planet, called Kepler-186f, was discovered using NASA’s Kepler spacecraft, which, like the Earth, is orbiting our sun. It stares out at distant stars and looks for planets orbiting them by detecting the way those stars dim when a planet passes between that star and Kepler’s eye.
Kepler has observed this particular planet multiple times as it has transited in front of its star, and this has allowed scientists to measure its size and its orbital period, which is 130 days. The planet is just 10 percent bigger than the Earth itself is.
“The significance of this result is that even though Kepler has previously discovered planets the size of the Earth, and it’s previously discovered planets that are in the habitable zone, this is the first time we’ve put the two of those together,” Stephen Kane, a professor of astrophysics at San Francisco University and one of the researchers on this project, tells Newsweek. He’s a co-author of a new paper in the journal Science announcing the results.
The planet is likely rocky, and not made of gas, says Kane. While it isn’t possible to literally see that there is water on the planet’s surface, the conditions imply that it is “likely to have the properties required to maintain reservoirs of liquid water,” as the Science article concludes. More good news in the search for planets where the conditions are right for having liquid water is the fact that the kind of star this Earth-sized planet is orbiting, an M-dwarf star, is “the most common type of star in the universe—far more common than the sun,” says Kane. “That’s really great news for habitability.”
The implication is that if there can be an Earth-sized planet orbiting such a common kind of star and within the habitable zone, there might be more of these planets where the conditions are right for water.
Ravi Kopparapu, a planetary scientist at The Pennsylvania State University, is an expert on the habitable zone and notes that Kepler-186f is similar to, but smaller than, a planet outside of our solar system called Kepler-62f, which is also terrestrial and in the habitable zone.
But this new find is closer to Earth size’s than that planet. (After a planet gets to be about 1.5 times the size of Earth is, its gravity attracts hydrogen and helium and makes it unlikely to have liquid water on its surface.) “I think it’s pretty pretty cool that they found this planet,” he says. “This shows that potential habitable planets are more common than our estimates.”
Wise words from GE
For the first time, scientists have discovered an Earth-size alien planet in the habitable zone of its host star, an “Earth cousin” that just might have liquid water and the right conditions for life.
Image 1: This artist illustration shows what it might be like to stand on the surface of the planet Kepler-186f, the first-ever Earth-size planet to be found in the habitable zone of its star. Credit: Danielle Futselaa
Image 2: This artist illustration shows the planet Kepler-186f, the first Earth-size alien planet discovered in the habitable zone of its star. Credit: NASA Ames/SETI Institute/JPL-CalTech
The newfound planet, called Kepler-186f, was first spotted by NASA’s Kepler space telescope and circles a dim red dwarf star about 490 light-years from Earth. While the host star is dimmer than Earth’s sun and the planet is slightly bigger than Earth, the positioning of the alien world coupled with its size suggests that Kepler-186f could have water on its surface, scientists say. You can learn more about the amazing alien planet find in a video produced by Space.com.
"One of the things we’ve been looking for is maybe an Earth twin, which is an Earth-size planet in the habitable zone of a sunlike star," Tom Barclay, Kepler scientist and co-author of the new exoplanet research, told Space.com. "This [Kepler-186f] is an Earth-size planet in the habitable zone of a cooler star. So, while it’s not an Earth twin, it is perhaps an Earth cousin. It has similar characteristics, but a different parent."
Scientists think that Kepler-186f — the outermost of five planets found to be orbiting the star Kepler-186 — orbits at a distance of 32.5 million miles (52.4 million kilometers), theoretically within the habitable zone for a red dwarf.
Earth orbits the sun from an average distance of about 93 million miles (150 million km), but the sun is larger and brighter than the Kepler-186 star, meaning that the sun’s habitable zone begins farther out from the star by comparison to Kepler-186.
"This is the first definitive Earth-sized planet found in the habitable zone around another star," Elisa Quintana, of the SETI Institute and NASA’s Ames Research Center and the lead author of a new study detailing the findings, said in a statement.
Other planets of various sizes have been found in the habitable zones of their stars. However, Kepler-186f is the first alien planet this close to Earth in size found orbiting in that potentially life-supporting area of an extrasolar system, according to exoplanet scientists.