Cosmic ‘web’ seen for first time
The hidden tendrils of dark matter that underlie the visible Universe may have been traced out for the first time.
Cosmology theory predicts that galaxies are embedded in a cosmic web of “stuff”, most of which is dark matter.
Astronomers obtained the first direct images of a part of this network, by exploiting the fact that a luminous object called a quasar can act as a natural “cosmic flashlight”.
The universe is mostly hydrogen and ignorance
John Dobson, telescope designer, former monk and open source astronomy advocate, dies at 98
All Of The Asteroids That Could Potentially End The World
Here’s the path of the nearly 1,400 asteroids that would cause “major devastation” if they hit our planet.
It’s no surprise that NASA is keeping track of all potentially hazardous objects, or PHOs, that surround our planet. If it’s closer than 4.6 million miles away and larger than about 350 feet in diameter, NASA’s watching it. And if a comet or asteroid’s orbit comes close enough to ours that there’s some potential for it to collide with our planet, NASA classifies it as a PHO. If something that size smacked Earth, it’d cause a major tsunami (if it hit water) or major regional destruction (if it hit land).
There are 1,397 known potentially hazardous asteroids (PHAs) at the moment, which you can see in this list. (The other PHOs are comets.) But why look at a list when you can look at a massive gorgeous picture? The image above, taken from NASA/JPL’s Photojournal, shows all 1,397 of those PHAs as represented by their orbits. Kind of amazing that we haven’t been hit by one, isn’t it?
The GRAIL mission was launched by NASA on September 10, 2011 and consisted of two small spacecraft, GRAIL A and GRAIL B. The acronym GRAIL stands for Gravity Recovery and Interior Laboratory and aimed to measure in very high quality the gravitational field of the moon. The two spacecraft, nicknamed Ebb and Flow, orbited the Moon for almost a year, starting on 31 December 2011, and ending on December 17, 2012 when they both impacted the surface of the moon. In the images generated, see above, the red zones are areas of above average gravitational pull, while blue areas are below the average gravitational attraction. The data gathered by Ebb and Flow will be used to help create much more accurate fuel consumption models for future missions to and around the moon.
Images 1 and 2: Living pluteus larva of the sea biscuit Clypeaster subdepressus under polarized light microscopy. Only the skeleton remains visible. Photos by Bruno C. Vellutini (Wikimedia; Flickr); cc-by-sa
Image 3: Pluteus larva via ccNeLaS
Image 4: Developing pluteus larva. Via Wikimedia. Public domain
Image 5: Sea urchin development tattoo via The Loom
Caption: “Greetings! Here’s a pic of my science tat. I studied sea urchin development for my dissertation. Upon completion 2 yrs ago, I awarded myself this tat for my academic achievement. The tat is of a sea urchin egg, 2 cell embryo, blastula, gastrula, prism stage and pluteus larval stage. Or as my friend’s say, an orange developing into an Alien face-grabber.”
Ross Lovegrove for Lasvit: Nodules
Using glass as an optical reservoir, the Nodules are handmade spherical lenses fused together in the making process to harness the natural physics of the material. A fiber optic light source delivers an intense white light from a remote point so that the relationship between the stem and Nodule is minimized and mysterious. The unique installations rise from the floor in clusters.
In the ocean, many forces compete in driving convection, including the temperature and salinity of the water. In the laboratory, it’s possible to mimic these characteristics of oceanic circulation using two different fluids driven by temperature and concentration differences. Recently, researchers were exploring this problem—with the added twist of tilting the fluids ~1 degree—when they discovered a surprising result. After an extended time, the convection self-organized into alternating parallel columns of ascending (dark) and descending (light) fluid. The researchers nicknamed this behavior super-highway convection. Read more about it here or in their paper. (Video credit: F. Croccolo et al; submitted by A. Vailati)
Helicopter rotor wake simulation from
Black Hawk Rotor Vortex Wake
“Aft view of the UH-60 helicopter rotor detatched eddy simulation showing the 3D nature of the vortex wake. Note the separated flow leaving the centerbody in the middle of the image, and the uneven wake separation due to the blade motion.
Investigator: Neal Chaderjian, NASA Ames Research Center, Moffett Field, Ca
Visualization: Tim Sandstrom, NASA/ Ames
More info available here: www.nas.nasa.gov/SC12/demos/demo1.html
Follow us on Twitter: www.twitter.com/NASA_Supercomp ”
Animated top view here
Mushroom vortices in round jet
From the Gallery of Fluid Motion (probably somewhere deep in the archives?)
Spherulites of lead chromate (Crocoite) on the surface of a decorative glaze (60x)
Image 1: ”A dish of millipedes under UV light. Most of the ones fluorescing in blue are Semionellus placidus, while the two fluorescing red are Pseudopolydesmus serratus. Red fluorescence under UV hasn’t been reported before in arthropods, to my knowledge.”
Photos by Derek Hennen. Check out his blog post for more field notes and details on identification!
Image 2: Semionellus placidus, photo by Derek Hennen (source)
Orsima ichneumon (Salticidae): a mimic of mutillid wasps
Gunung Leuser National Park, Sumatra
Photo by Arthur Anker:
“Jewel tortoise beetle sleeping”
Photo by Arthur Anker, Brazilian Amazon, 2012:
Diagram by Edward Ott, Scholarpedia:
Figure 1: (a) Double well potential V(x) , and (b) the resulting basins of attraction.