This seemed like a good day to post some rainbow laser modes!
Light in a circular cavity makes a variety of standing wave patterns, some of which look like flowers, wagon wheels, or even tie-fighter spaceships. These images are from my simulations of the light in the cavities of nanolasers - each pattern is called a mode, and the smaller the laser, the simpler the mode tends to be.
In our lasers, the modes that tend to do the best are the whispering gallery modes - for example, the mode at the upper center. Whispering gallery modes get their name from the whispering gallery phenomenon first noticed with sound waves in cathedral domes. People noticed that if they stood along the perimeter of some cathedral domes, the sound waves from a whisper would bounce along the walls of the dome, and could be clearly heard at certain other places along the dome’s perimeter. In the case of our lasers, it’s light that bounces around the laser cavity - wavelengths that make an integer number of oscillations in one round trip end up forming a sort of circular standing wave. Whispering gallery modes appear not just for light and sound, but for other kinds of waves as well, like matter waves and gravitational waves.
By NASA
NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission has identified the process that appears to have played a key role in the transition of the Martian climate from an early, warm and wet environment that might have supported surface life to the cold, arid planet Mars is today.
(excerpt - click the link for the complete article and cool video animation)
The finding suggests that quasars—the brilliant cores of active galaxies – may commonly host two central supermassive black holes, which fall into orbit about one another as a result of the merger between two galaxies. Like a pair of whirling skaters, the black-hole duo generates tremendous amounts of energy that makes the core of the host galaxy outshine the glow of its population of billions of stars, which scientists then identify as quasars.
Scientists looked at Hubble archival observations of ultraviolet radiation emitted from the center of Mrk 231 to discover what they describe as “extreme and surprising properties.”
If only one black hole were present in the center of the quasar, the whole accretion disk made of surrounding hot gas would glow in ultraviolet rays. Instead, the ultraviolet glow of the dusty disk abruptly drops off toward the center. This provides observational evidence that the disk has a big donut hole encircling the central black hole. The best explanation for the donut hole in the disk, based on dynamical models, is that the center of the disk is carved out by the action of two black holes orbiting each other. The second, smaller black hole orbits in the inner edge of the accretion disk, and has its own mini-disk with an ultraviolet glow.
Read more ~ NASA.gov
Image: This artistic illustration is of a binary black hole found in the center of the nearest quasar to Earth, Markarian 231. Credits: NASA, ESA, and G. Bacon (STScI)
Nanoparticles are particles between 1 and 100 nanometers in size. In nanotechnology, a particle is defined as a small object that behaves as a whole unit with respect to its transport and properties.Particles are further classified according to diameter.[1] Ultrafine particles are the same as nanoparticles and between 1 and 100 nanometers in size, fine particles are sized between 100 and 2,500 nanometers, and coarse particles cover a range between 2,500 and 10,000 nanometers. Nanoparticle research is currently an area of intense scientific interest due to a wide variety of potential applications in biomedical, optical and electronic fields.[2][3][4][5] TheNational Nanotechnology Initiative has led to generous public funding for nanoparticle research in the United States.
[Source]
Phroyd
On Wednesday, Oct. 28 and Friday, Nov. 6, Commander Scott Kelly and Flight Engineer Kjell Lindgren will perform spacewalks in support of space station assembly and maintenance. You can watch both of these events live on NASA Television. But, before you do, here are 7 things to know:
1. What’s the Point of a Spacewalk?
Spacewalks are important events where crew members repair, maintain and upgrade parts of the International Space Station. Spacewalks can also be referred to as an EVA – Extravehicular Activity. On Wednesday, Oct. 28, Commander Scott Kelly and Flight Engineer Kjell Lindgren will complete a spacewalk. During this time they will service the Canadarm2 robotic arm, route cables for a future docking port, and place a thermal cover over a dark matter detection experiment, which is a state-of-the-art particles physics detector that has been attached to the station since 2011.
2. What Do They Wear?
The Extravehicular Mobility Unit (EMU) spacewalking suit weighs around 350 pounds. It’s weightless in space, but mass is still very real. The EMU provides a crew member with life support and an enclosure that enables them to work outside the space station. The suit provides atmospheric containment, thermal insulation, cooling, solar radiation protection and micrometeoroid/orbital debris protection.
3. How Long Are Spacewalks?
Spacewalks typically last around 6 ½ hours, but can be extended to 7 or 8 hours, if necessary. The timeline is designed to accommodate as many tasks as possible, as spacewalks require an enormous amount of work to prepare.
4. What About Eating and Drinking?
Before a spacewalk astronauts eat light, usually something like a protein bar. The spacesuits also have a drink bag inside, and there is a bite valve that allows ready access to water.
5. What About Communication?
Spacewalkers wear a ‘comm’ cap that allows them to constantly communicate with astronauts inside the space station that are helping with the walk, and with mission control. Astronauts also wear a checklist on their left wrist called a “cuff checklist”. This list contains emergency procedures.
6. What About Light?
Something that most people don’t realize about spacewalks is that the crew will experience a sunrise/sunset every 45 minutes. Luckily, their spacesuits are equipped with lights that allow them to see in times of darkness.
7. How Do They Stay Safe?
When on a spacewalk, astronauts use safety tethers to stay close to their spacecraft. One end of the tether is hooked to the spacewalker, while the other end is connected to the vehicle. Another way astronauts stay safe is by wearing a SAFER, which is a Simplified Aid for EVA Rescue. This device is worn like a backpack and uses small jet thrusters to let an astronaut move around in space.
You can watch both of the upcoming spacewalks live on: NASA Television or the NASA App, or follow along on @Space_Station Twitter.
Wednesday, Oct. 28: Coverage begins at 6:30 a.m. EDT. Spacewalk begins at 8:10 a.m.
Friday, Nov. 6: Coverage begins at 5:45 a.m. EDT. Spacewalk begins at 7:15 a.m.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com
Looks like they could kill you but is actually a cinnamon roll: W Boson
Looks like a cinnamon roll but could actually kill you: Photon
Looks like they could kill you and can actually kill you: Z Boson
Looks like a cinnamon roll and is actually a cinnamon roll: Gluon
Spinnamon Roll: Higgs Boson
Scientists have developed a novel method to calculate the distances to stars, and it could be useful in helping map the size of galaxies. The study is published in the Monthly Notices of the Royal Astronomical Society.
The researchers from the University of Cambridge examined what are known as “stellar twins.” These are stars that are identical, with exactly the same chemical composition, which can be worked out from their spectra – the type of light they emit. If they were both placed at the same distance from Earth, they would shine with equal brightness.
So the team realized that if the distance to just one of the stars was known, the other could be calculated relatively easily based on how brightly it was shining. The dimmer it is, the further away it is, and vice versa. The method can be used to accurately measure the distance.
“It’s a remarkably simple idea – so simple that it’s hard to believe no one thought of it before,” said lead author Dr Paula Jofre Pfeil, from Cambridge’s Institute of Astronomy, in a statement. “The further away a star is, the fainter it appears in the sky, and so if two stars have identical spectra, we can use the difference in brightness to calculate the distance.”
Read more ~ IFL Science
Photo credit: RealCG Animation Studio. Shutterstock.
The Atom and Its Quantum Mirror Image: Physicists Experimentally Produces Quantum-Superpositions, Simply Using a Mirror (click thru for ScienceDaily article)
_________
“This uncertainty about the state of the atom does not mean that the measurement lacks precision,” Jörg Schmiedmayer (TU Vienna) emphasizes. “It is a fundamental property of quantum physics: The particle is in both of the two possible states simultaneousely, it is in a superposition.” In the experiment the two motional states of the atom – one moving towards the mirror and the other moving away from the mirror – are then combined using Bragg diffraction from a grating made of laser light. Observing interference it can be directly shown that the atom has indeed been traveling both paths at once…“
* (You look inside...) * (Inside the joke book is a quantum physics book.)
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