As her new book on the origins of the universe is published, the Albanian-American scientist explains how her work on multiverse theory influenced Stephen Hawking.
Category: cosmology – Page 220
Then a mere scientist pulled it off. Otto von Guericke invented a pump to suck the air from within a hollow copper sphere, establishing perhaps the first high-quality vacuum on Earth. In a theatrical demonstration in 1,654, he showed that not even two teams of horses straining to rip apart the watermelon-size ball could overcome the suction of nothing.
Since then, the vacuum has become a bedrock concept in physics, the foundation of any theory of something. Von Guericke’s vacuum was an absence of air. The electromagnetic vacuum is the absence of a medium that can slow down light. And a gravitational vacuum lacks any matter or energy capable of bending space. In each case the specific variety of nothing depends on what sort of something physicists intend to describe. “Sometimes, it’s the way we define a theory,” said Patrick Draper, a theoretical physicist at the University of Illinois.
As modern physicists have grappled with more sophisticated candidates for the ultimate theory of nature, they have encountered a growing multitude of types of nothing. Each has its own behavior, as if it’s a different phase of a substance. Increasingly, it seems that the key to understanding the origin and fate of the universe may be a careful accounting of these proliferating varieties of absence.
On the other side of a black hole is the other side. It’s not two dimensional like the artists renderings. The question is… what’s inside of it?
Experiments from Artemis I are headed to the moon an asteroid and beyond. See this mission overview which delves into the ten cubesat secondary payloads and the manikin experiments flying on Artemis I.
Worm-hole generators by the pound mass: https://greengregs.com/
For gardening in your Lunar habitat Galactic Gregs has teamed up with True Leaf Market to bring you a great selection of seed for your planting. Check it out: http://www.pntrac.com/t/TUJGRklGSkJGTU1IS0hCRkpIRk1K
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Did the Big Bang happen?
Posted in cosmology, mathematics, open access, physics
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Physicists have many theories for the beginning of our universe: A big bang, a big bounce, a black hole, a network, a collision of membranes, a gas of strings, and the list goes on. What does this mean? It means we don’t know how the universe began. And the reason isn’t just that we’re lacking data, the reason is that science is reaching its limits when we try to understand the initial condition of the entire universe.
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The Poplawski paper about how the universe might have been born from a black hole is here: https://link.springer.com/article/10.1007/s10714-021-02790-7
00:00 Intro.
00:25 The Big Bang Theory.
03:47 Why So Many Other Theories?
04:53 The Problem With Cosmology.
07:30 The Importance of Simplicity.
10:57 Stories of Creation.
15:35 Sponsor Message
This isn’t what we see. What we observe is that more distant galaxies have a dimmer surface brightness than closer ones. The amount of dimming is proportional to the amount of redshift the galaxy has. You might think this proves that all those distant galaxies are speeding away from us, but it actually doesn’t. If those distant galaxies were speeding away, you’d have two dimming effects. The red shift and the ever-increasing distance. The Tolman test predicts that in a simple expanding universe, the surface brightness of galaxies should diminish proportional to both redshift and distance. We only see the effects of redshift.
This fact has led some to propose a static universe where light spontaneously loses energy over time. It’s the so-called tired light hypothesis, and it’s very popular among big bang opponents. If the universe is static and light is tired, then the Tolman test predicts exactly what we observe. Hence no big bang.
Back in 2014, Eric Lerner et al. published a paper making exactly this point. It caused a flurry of “Big Bang Dead!” articles in the popular media. The latest claims about Webb killing the big bang began with a popular article by the same Eric Lerner. So here we are. In fairness, back in 2014, the Hubble observations supported Lerner’s claim, and so do the latest Webb observations. But what Lerner conveniently omitted from his paper is that the Hubble and Webb observations also support the LCDM model.
A mathematical shortcut for analyzing black hole collisions works even in cases where it shouldn’t. As astronomers use it to search for new classes of hidden black holes, others wonder: Why?
The oldest radio galaxy yet discovered is hidden in a cluster.
Astronomers claim to have found the oldest fossil radio galaxy yet discovered, hiding in a cluster. The brightest galaxy in the cluster erupted as a result of supermassive black hole activity, blowing massive bubbles of radio light into space, according to a report published by ScienceAlert.
“These newly discovered bubbles — known as radio lobes, or a radio galaxy — are the oldest of their kind we’ve ever seen,” claimed the astronomers’ team led by Surajit Paul and Savitribai Phule from Pune University in India.
A second team of astronomers led by Gopal Krishna of the University of Mumbai also discovered a pair of younger lobes that are linked to the same parent galaxy.
If we had been around and able to see into the heart of galaxy cluster Abell 980 around 260 million years ago, we may have seen something very spectacular indeed.
The brightest galaxy in the cluster erupted, the result of activity from its supermassive black hole, an event that would go on to blow massive bubbles emitting radio light out into space.
What is a wormhole?
Posted in cosmology
Are you curious?
Imagine two towns on two opposite sides of a mountain. People from these towns would probably have to travel all the way around the mountain to visit one another. But, if they wanted to get there faster, they could dig a tunnel straight through the mountain to create a shortcut. That’s the idea behind a wormhole.
A wormhole is like a tunnel between two distant points in our universe that cuts the travel time from one point to the other. Instead of traveling for many millions of years from one galaxy to another, under the right conditions, one could theoretically use a wormhole to cut the travel time down to hours or minutes.
You’ll often see wormholes in science fiction as a way to travel across the Galaxy.
Imagine two towns on two opposite sides of a mountain. People from these towns would probably have to travel all the way around the mountain to visit one another. But, if they wanted to get there faster, they could dig a tunnel straight through the mountain to create a shortcut. That’s the idea behind a wormhole.
A wormhole is like a tunnel between two distant points in our universe that cuts the travel time from one point to the other. Instead of traveling for many millions of years from one galaxy to another, under the right conditions, one could theoretically use a wormhole to cut the travel time down to hours or minutes.
Because wormholes represent shortcuts through space-time, they could even act like time machines. You might emerge from one end of a wormhole at a time earlier than when you entered its other end.