Jump to content

PSA videos and other excitement

Recommended Posts

  • Replies 68
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

Share something that you think changes the way you can see, understand, or experience the world. Help distribute a little more positive future with a curated video or other content, one item per post

Well, you did say "...something that you think changes the way you can see, understand, at or experience the world."  Scripters deal with rotations every time we have to open a door or make a vehicle

  • 2 weeks later...
  • 2 weeks later...
  • 2 weeks later...

Carl Schoonover and Andrew Fink are confused. As neuroscientists, they know that the brain must be flexible but not too flexible. It must rewire itself in the face of new experiences, but must also consistently represent the features of the external world. How? The relatively simple explanation found in neuroscience textbooks is that specific groups of neurons reliably fire when their owner smells a rose, sees a sunset, or hears a bell. These representations—these patterns of neural firing—presumably stay the same from one moment to the next. But as Schoonover, Fink, and others have found, they sometimes don’t. They change—and to a confusing and unexpected extent.

Schoonover, Fink, and their colleagues from Columbia University allowed mice to sniff the same odors over several days and weeks, and recorded the activity of neurons in the rodents’ piriform cortex—a brain region involved in identifying smells. At a given moment, each odor caused a distinctive group of neurons in this region to fire. But as time went on, the makeup of these groups slowly changed. Some neurons stopped responding to the smells; others started. After a month, each group was almost completely different. Put it this way: The neurons that represented the smell of an apple in May and those that represented the same smell in June were as different from each other as those that represent the smells of apples and grass at any one time.

This is, of course, just one study, of one brain region, in mice. But other scientists have shown that the same phenomenon, called representational drift, occurs in a variety of brain regions besides the piriform cortex. Its existence is clear; everything else is a mystery. 

(from https://www.theatlantic.com/science/archive/2021/06/the-brain-isnt-supposed-to-change-this-much/619145/)

Link to post
Share on other sites



Physicists Study How Universes Might Bubble Up and Collide

Charlie Wood, Contributing Writer

Quanta Magazine, January 25, 2021

The researchers realized that while space may have stopped inflating here (in our bubble universe) and there (in other bubbles), quantum effects should continue to inflate most of space, an idea known as eternal inflation.

The difference between bubble universes and their surroundings comes down to the energy of space itself. When space is as empty as possible and can’t possibly lose more energy, it exists in what physicists call a “true” vacuum state. Think of a ball lying on the floor — it can’t fall any further. But systems can also have “false” vacuum states. Imagine a ball in a bowl on a table. The ball can roll around a bit while more or less staying put. But a large enough jolt will land it on the floor — in the true vacuum.

In the cosmological context, space can get similarly stuck in a false vacuum state. A speck of false vacuum will occasionally relax into true vacuum (likely through a random quantum event), and this true vacuum will balloon outward as a swelling bubble, feasting on the false vacuum’s excess energy, in a process called false vacuum decay. It’s this process that may have started our cosmos with a bang. “A vacuum bubble could have been the first event in the history of our universe,” said Hiranya Peiris, a cosmologist at University College London.

But physicists struggle mightily to predict how vacuum bubbles behave. A bubble’s future depends on countless minute details that add up. Bubbles also change rapidly — their walls approach the speed of light as they fly outward — and feature quantum mechanical randomness and waviness. Different assumptions about these processes give conflicting predictions, with no way to tell which ones might resemble reality. It’s as though “you’ve taken a lot of things that are just very hard for physicists to deal with and mushed them all together and said, ‘Go ahead and figure out what’s going on,’” Braden said.

(from https://www.quantamagazine.org/physicists-study-how-our-universe-might-have-bubbled-up-in-the-multiverse-20210125/)




Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...