Dragon Snake (Xenodermus javanicus)
How nerve cells within the brain communicate with each other over long distances has puzzled scientists for decades. The way networks of neurons connect and how individual cells react to incoming pulses in principle makes communication over large distances impossible. Scientists from Germany and France provide now a possible answer how the brain can function nonetheless: by exploiting the powers of resonance.
As Gerald Hahn, Alejandro F. Bujan and colleagues describe in the journal PLoS Computational Biology, the ability of networks of neurons to resonate can amplify oscillations in the activity of nerve cells, allowing signals to travel much farther than in the absence of resonance. The team from the cluster of excellence BrainLinks-BrainTools and the Bernstein Center at the University of Freiburg and the UNIC department of the French Centre national de la recherche scientifique in Gif-sur-Yvette created a computer model of networks of nerve cells and analyzed its properties for signal propagation.
Gerald Hahn, Alejandro F. Bujan, Yves Frégnac, Ad Aertsen, Arvind Kumar. Communication through Resonance in Spiking Neuronal Networks. PLoS Computational Biology, 2014; 10 (8): e1003811 DOI: 10.1371/journal.pcbi.1003811
Resonance in the activity of nerve cells (left) allows activity within the brain to travel over large distances, e.g. from the back of the head to the front during the processing of visual stimuli. Credit: Gunnar Grah/BrainLinks-BrainTools
Scientists have discovered the largest black holes yet, and they’re far bigger than researchers expected based on the galaxies in which they were found. The discovery suggests we have much to learn about how monster black holes grow, scientists said.
All large galaxies are thought to harbor super-massive black holes at their hearts that contain millions to billions of times the mass of our sun. Until now, the largest black hole known was a mammoth dwelling in the giant elliptical galaxy Messier 87. This black hole has a mass 6.3 billion times that of the sun.
Now research suggests black holes in two nearby galaxies are even bigger. The scientists used the Gemini and Keck observatories in Hawaii and the McDonald Observatory in Texas to monitor the velocities of stars orbiting around the centers of a pair of galaxies. These velocities reveal the strength of the gravitational pull on those stars, which in turn is linked with the masses of the black holes lurking there.
The new findings suggest that one galaxy, known as NGC 3842, the brightest galaxy in the Leo cluster of galaxies nearly 320 million light years distant, has a central black hole 9.7 billion solar masses large. The other, named NGC 4889, the brightest galaxy in the Coma cluster more than 335 million light years away, has a black hole of comparable or larger mass. Both encompass regions or “event horizons” about five times the distance from the sun to Pluto.
"For comparison, these black holes are 2,500 times as massive as the black hole at the center of the Milky Way galaxy, whose event horizon is one-fifth the orbit of Mercury," said study lead author Nicholas McConnell at the University of California, Berkeley. Astronomers had suspected that black holes more than 10 billion solar masses large exist, based on light from quasars, cosmic objects from the early universe that are no more than a light year or two across but are thousands of times brighter than our entire galaxy.
The light of quasars is thought to come from matter driven to incandescent brightness as it spirals at high speeds into supermassive black holes. This is the first time scientists have detected black holes approaching such theorized giants in size.
"These two new supermassive black holes are similar in mass to young quasars, and may be the missing link between quasars and the supermassive black holes we see today," said study co-author Chung-Pei Ma, an astrophysicist at the University of California, Berkeley.
The geometry of diatoms, desmids and other algae.
It’s time for the most intense nights of Perseid meteor shower (August 10–13; Tuesday night with as many as 100 ‘shooting stars’ per hour), here are some tips:
- Give your eyes 20 minutes to adjust to the dark. Avoid looking at the moon, your phone or any device that shows light – any exposure to bright lights will instantly ruin your eye’s acclimatization to the dark
- If possible go outside the city, or search for good local stargazing places
- For the best chances of spotting a shooting star, scan the whole sky repeatedly
- Be prepared to spend a few hours sitting outside. Meteor showers can be seen as soon as it gets dark, but better viewing begins about 11 pm
- If you have binoculars or a telescope, take them with you. While you’re there, you can also look for constellations, stars, and planets
(Gif: Exploding Perseid Meteor filmed by
if you aren’t hyped about synthetic life and colonizing space then get out of my face
Perseid Meteor Shower
Not as great as last year but still worthy of watching. The Full Moon will compete with the shower this year, lowering the peak-rates to around 40 or 60 meteors per hour at best, even in the darkest of skies. The peak time is Aug 10-13 but you can see meteors for about a week before and after, so start watching now! The earlier you watch, the less the moon will be in the way, so watching a few days before the peak might actually be better if not the same. For more stargazing events this month, see What’s Up for August. Also, Semi-Relevant/Informative post from last year