This Liquid Is Boiling And Freezing Simultaneously Because It’s Reaching Its ‘triple Point,’ Which

Eggs Submerged Deep Under Water

The first egg imploded at around 416 feet below sea level. Eggs are porous, which means that air and moisture can pass through the shell. So in this experiment, diver Jim Varnum spray-painted the right egg to seal it. The left egg wasn’t sealed so it survived longer and didn’t implode until it was 1,706 feet below the surface (or 0.3 of a mile). (Source: Jim Varnum / Via vimeo.com)

Shown above are a trio of microscale rockets, each about 10 microns in length. These tiny rockets are roughly cylindrical in shape, with a narrower diameter at the front than the back. Like their space-faring brethren, these microrockets are chemically propelled. They draw in fuel from their surroundings, which reacts with the catalysts coating the interior of the microrocket to produce gases. Those gases bubble out the back end of the microrocket, creating thrust capable of propelling the rockets more than 1000 body lengths/second. Researchers have already demonstrated that these tiny rockets can haul cargo along with them. Scientists hope one day to use these self-propelled microrockets to help deliver drugs or isolate cancer cells. (Image credit: J. Li et al., source)

Wind from the Stars

The Sun’s outermost layer is called the corona, and even though it’s the coolest part of the Sun, it still reaches temperatures of 1.1 million degrees Celsius. Because it’s so hot, its charged particles (plasma) are moving so fast that the Sun’s gravity can’t hold onto them, and they stream away into space in great, constant gusts of solar wind.

Though released in all directions around the Sun, the solar wind isn’t uniform. It’s released at different speeds and temperatures. When released from coronal holes at the poles of the Sun, where temperature is low and the magnetic field is weak, the solar wind can reach speeds of up to 800 kilometres per second. When released from the coronal streamer belt around the Sun’s equator, the solar wind is twice as hot but travels more slowly, at 300 kilometres per second. These variations of solar wind can interact with each other, contributing to the complexity of solar weather.

So what happens when this fast, hot radiation sweeps over the planets?

The Earth is protected from the brunt of charged particles by our magnetic field. Produced by convection in the Earth’s core, our magnetic field casts a huge “shield” into space, deflecting most of the radiation. The force of the wind is actuslly so strong that the field has been bent out of shape. Instead of surrounding us in a sphere, it’s been forced into an octopus shape: squashed up on the side of the Sun, and streaming out like tentacles on the other wise.

However, some charged particles do make it through to Earth. As the different wind speeds buffer us, particles with particularly high energies stream down to the weakest parts of our magnetic field—the poles—and collide with gas particles in the atmosphere, causing them to release bursts of light we know as aurorae.

During solar maximums, when the Sun is at its most active, it will sometimes eject huge bursts of plasma called Coronal mass Ejections. These are stronger than the normal solar wind and can create magnificent aurorae all over the world.

Other planets and moons aren’t as lucky as Earth. Our Moon, for example, has no magnetic field to protect it and so is hit directly by the solar winds. Mercury has a magnetic field but because it’s closest to the Sun, it’s hit the hardest by Coronal Mass Ejections. Mars has no magnetic field either, so if we were ever to send humans to the Red Planet, the effects of solar radiation would be incredibly important to protect against.

Image Credit: Wikimedia Commons

This is what happens when you cut a water droplet using a super hydrophobic knife on a surface that doesn’t get wet. 

Juno captured the thick atmosphere (hydrogen, helium, small amounts of ammonium hydrosulfide) of Jupiter.

The World of Everyday Experience, In One Equation

A galaxy on the edge

This spectacular image was captured by the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys (ACS). The bright streak slicing across the frame is an edge-on view of galaxy NGC 4762, and a number of other distant galaxies can be seen scattered in the background.

NGC 4762 lies about 58 million light-years away in the constellation of Virgo (The Virgin). It is part of the Virgo Cluster, hence its alternative designation of VCC 2095 for Virgo Cluster Catalogue entry. This catalogue is a listing of just over 2000 galaxies in the area of the Virgo Cluster. The Virgo Cluster is actually prominently situated, and lies at the centre of the larger Virgo supercluster, of which our galaxy group, the Local Group, is a member.

Previously thought to be a barred spiral galaxy, NGC 4762 has since been found to be a lenticular galaxy, a kind of intermediate step between an elliptical and a spiral. The edge-on view that we have of this particular galaxy makes it difficult to determine its true shape, but astronomers have found the galaxy to consist of four main components — a central bulge, a bar, a thick disc and an outer ring.

The galaxy’s disc is asymmetric and warped, which could potentially be explained by NGC 4762 violently cannibalising a smaller galaxy in the past. The remains of this former companion may then have settled within NGC 4762’s disc, redistributing the gas and stars and so changing the disc’s morphology.

NGC 4762 also contains a Liner-type Active Galactic Nucleus, a highly energetic central region. This nucleus is detectable due to its particular spectral line emission, which acts as a type of “atomic fingerprint”, allowing astronomers to measure the composition of the region.

Image credit: ESA/Hubble & NASA

NASA’s Fermi Satellite Celebrates 10 Years of Discoveries

On June 11, NASA’s Fermi Gamma-ray Space Telescope celebrates a decade of using gamma rays, the highest-energy form of light in the cosmos, to study black holes, neutron stars, and other extreme cosmic objects and events.

Left: A STEREO B image of the far side of the sun during the Sept. 1, 2014, solar eruption. Right: The Earth-facing side of the sun at the same time as seen by NASA’s Solar Dynamics Observatory. The view includes the area from which NASA’s Fermi detected high-energy gamma rays. Includes animated gif. Credit: NASA/STEREO and NASA/SDO

A rupture in the crust of a highly magnetized neutron star, shown here in an artist’s rendering, can trigger high-energy eruptions. Fermi observations of these blasts include information on how the star’s surface twists and vibrates, providing new insights into what lies beneath. Credits: NASA’s Goddard Space Flight Center/S. Wiessinger 

Fermi finds the first extragalactic gamma-ray pulsar. NASA’s Fermi Gamma-ray Space Telescope has detected the first extragalactic gamma-ray pulsar, PSR J0540-6919, near the Tarantula Nebula (top center) star-forming region in the Large Magellanic Cloud, a satellite galaxy that orbits our own Milky Way. Fermi detects a second pulsar (right) as well but not its pulses. PSR J0540-6919 now holds the record as the highest-luminosity gamma-ray pulsar. The angular distance between the pulsars corresponds to about half the apparent size of a full moon. Background: An image of the Tarantula Nebula and its surroundings in visible light. Credit: NASA’s Goddard Space Flight Center; background: ESO/R. Fosbury (ST-ECF)

These maps, both centered on the north galactic pole, show how the sky looks at gamma-ray energies above 100 million electron volts (MeV). Left: The sky during a three-hour interval prior to the detection of GRB 130427A. Right: A three-hour interval starting 2.5 hours before the burst and ending 30 minutes into the event, illustrating its brightness relative to the rest of the gamma-ray sky. GRB 130427A was located in the constellation Leo near its border with Ursa Major, whose brightest stars form the familiar Big Dipper. For reference, this image includes the stars and outlines of both constellations. Labeled. Credit: NASA/DOE/Fermi LAT Collaboration.

Novae typically originate in binary systems containing sun-like stars, as shown in this artist’s rendering. A nova in a system like this likely produces gamma rays (magenta) through collisions among multiple shock waves in the rapidly expanding shell of debris. Credit: NASA’s Goddard Space Flight Center/S. Wiessinger

Gamma Rays in Active Galactic Nuclei. 

Gamma-ray Burst Photon Delay as Expected by Quantum Gravity. Print resolution still. In this illustration, one photon (purple) carries a million times the energy of another (yellow). Some theorists predict travel delays for higher-energy photons, which interact more strongly with the proposed frothy nature of space-time. Yet Fermi data on two photons from a gamma-ray burst fail to show this effect, eliminating some approaches to a new theory of gravity. Credit: NASA/Sonoma State University/Aurore Simonnet

“Fermi’s first 10 years have produced numerous scientific discoveries that have revolutionized our understanding of the gamma-ray universe,” said Paul Hertz, Astrophysics Division director at NASA Headquarters in Washington. 

By scanning the sky every three hours, Fermi’s main instrument, the Large Area Telescope (LAT), has observed more than 5,000 individual gamma-ray sources, including an explosion called GRB 130427A, the most powerful gamma-ray burst scientists have detected.

In 1949, Enrico Fermi — an Italian-American pioneer in high-energy physics and Nobel laureate for whom the mission was named — suggested that cosmic rays, particles traveling at nearly the speed of light, could be propelled by supernova shock waves. In 2013, Fermi’s LAT used gamma rays to prove these stellar remnants are at least one source of the speedy particles.

Fermi’s all-sky map, produced by the LAT, has revealed two massive structures extending above and below the plane of the Milky Way. These two “bubbles” span 50,000 light-years and were probably produced by the supermassive black hole at the center of the galaxy only a few million years ago.

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'We've now seen the unseeable': Black hole photographed for the first time

Black holes have been mysterious and elusive — until now. Astronomers using the Event Horizon Telescope (EHT) have, for the first time, photographed one.

Black holes have been mysterious and elusive — until now. Astronomers using the Event Horizon Telescope (EHT) have, for the first time, photographed one.

“We’ve now seen the unseeable,” said Avery Broderick, a physicist at the University of Waterloo and the Perimeter Institute who was part of the international EHT research team. “Black holes are made real — they’re not just the scribblings on theorists’ chalkboards anymore, but they really are out there in the night.”

The image, which shows an orange ring around a round, black silhouette, is of the black hole at the centre of Messier 87 (M87), a galaxy 50 million light-years from Earth. This black hole is one of the most massive known: it’s six billion times more massive than our sun.

Black holes are so dense and have such strong gravity that anything that crosses their threshold — known as the event horizon — gets pulled into them, never to return. That includes both matter and light, making them black and invisible — and therefore very difficult to see and photograph.

An international team of more than 200 people spent more than a decade working to capture the image released today.

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Gas pillars inside the Orion Nebula