Why cutting-edge braneworld theories say our universe began in a white hole
Cosmologists behind braneworld theories see our universe as being a part of a complex inter-dimensional world.
Of all the theories in cosmology about how our universe was created, the braneworld theory presents perhaps one of the most exotic, hard-to-prove and yet potentially elegant solutions to how all this came to be.
The main idea here is that our three-dimensional universe is located on a brane (short for "membrane), which is a multi-dimensional object from string-theory. This brane of ours, say the scientists, is inside a hyper-dimensional space called the “bulk” or “hyperspace”. Interaction with extra dimensions and other moving branes can have an impact on our brane, with effects other cosmological models don’t account for.
In 1999, physicists Lisa Randall and Raman Sundry introduced a braneworld theory that received considerable attention. Under their theory, there can be other universes just a microscopic distance away from ours. But this distance “is measured in some fourth spatial dimension of which we are not aware,” explains Lisa Randall in her blog post explaining the ideas. Essentially, the visible universe is embedded in a larger universe.
“Because we are imprisoned in our three dimensions we can't directly detect these other universes,” continues Randall. “It's rather like a whole lot of bugs crawling around on a big, two-dimensional sheet of paper, who would be unaware of another set of bugs that might be crawling around on another sheet of paper that could be only a short distance away in the third dimension.”
A 2013 paper by physicists Razieh Pourhasan, Niayesh Afshordi, and Robert B. Mann, called “Out of the White Hole: A Holographic Origin for the Big Bang,” proposed that our universe is like a hologram, which exists on a 3D brane that was formed as a result of the collapse of a 4D black hole in the bulk universe. The process would be similar to how stars in our universe explode in supernovas, while their inner layers collapse and form black holes. Only in this case, a universe-creating "white hole" is generated. A whole hole is a hypothetical region of spacetime that you can't enter from the outside, but matter and light can escape it.
If you notice, this model doesn't require there being being a Big Bang to start off the universe's expansion.
“Astronomers measured that expansion and extrapolated back that the Universe must have begun with a Big Bang — but that is just a mirage,” said Afshordi, who led the study.
A similarly fascinating way of looking at white holes comes from physicist Nikodem Poplawski, who in 2010, while at Indiana University, proposed that when a dying star produces a black hole upon its collapse, at that same time a universe is born from a white hole on the other side of a wormhole.
This approach regards black holes and white holes as mouths of a wormhole also known as an Einstein-Rosen bridge.
In his paper, Poplawski showed through equations of the spiraling motion of matter falling into a black hole that wormholes were viable as an alternative explanation to the formation of “space-time singularities” (infinitely small points of infinite density), also predicted by Albert Einstein.
What does this mean for our own universe? It could have ”itself formed from inside a black hole existing inside another universe," explained Poplawski.
Check out this great explanation of the braneworld theory from the Caltech physicist Kip Thorne:
What can 3D printing do for medicine? The "sky is the limit," says Northwell Health researcher Dr. Todd Goldstein.
- Medical professionals are currently using 3D printers to create prosthetics and patient-specific organ models that doctors can use to prepare for surgery.
- Eventually, scientists hope to print patient-specific organs that can be transplanted safely into the human body.
- Northwell Health, New York State's largest health care provider, is pioneering 3D printing in medicine in three key ways.
Technology may soon grant us immortality, in a sense. Here's how.
- Through the Connectome Project we may soon be able to map the pathways of the entire human brain, including memories, and create computer programs that evoke the person the digitization is stemmed from.
- We age because errors build up in our cells — mitochondria to be exact.
- With CRISPR technology we may soon be able to edit out errors that build up as we age, and extend the human lifespan.
The controversial herbicide is everywhere, apparently.
- U.S. PIRG tested 20 beers and wines, including organics, and found Roundup's active ingredient in almost all of them.
- A jury on August 2018 awarded a non-Hodgkin's lymphoma victim $289 million in Roundup damages.
- Bayer/Monsanto says Roundup is totally safe. Others disagree.
The pizza giant Domino's partners with a Silicon Valley startup to start delivering pizza by robots.
- Domino's partnered with the Silicon Valley startup Nuro to have robot cars deliver pizza.
- The trial run will begin in Houston later this year.
- The robots will be half a regular car and will need to be unlocked by a PIN code.
Would you have to tip robots? You might be answering that question sooner than you think as Domino's is about to start using robots for delivering pizza. Later this year a fleet of self-driving robotic vehicles will be spreading the joy of pizza throughout the Houston area for the famous pizza manufacturer, using delivery cars made by the Silicon Valley startup Nuro.
The startup, founded by Google veterans, raised $940 million in February and has already been delivering groceries for Kroger around Houston. Partnering with the pizza juggernaut Domino's, which delivers close to 3 million pizzas a day, is another logical step for the expanding drone car business.
Kevin Vasconi of Domino's explained in a press release that they see these specially-designed robots as "a valuable partner in our autonomous vehicle journey," adding "The opportunity to bring our customers the choice of an unmanned delivery experience, and our operators an additional delivery solution during a busy store rush, is an important part of our autonomous vehicle testing."
How will they work exactly? Nuro explained in its own press release that this "opportunity to use Nuro's autonomous delivery" will be available for some of the customers who order online. Once they opt in, they'll be able to track the car via an app. When the vehicle gets to them, the customers will use a special PIN code to unlock the pizza compartment.
Nuro and its competitors Udelv and Robomart have been focusing specifically on developing such "last-mile product delivery" machines, reports Arstechnica. Their specially-made R1 vehicle is about half the size of a regular passenger car and doesn't offer any room for a driver. This makes it safer and lighter too, with less potential to cause harm in case of an accident. It also sticks to a fairly low speed of under 25 miles an hour and slams on the breaks at the first sign of trouble.
What also helps such robot cars is "geofencing" technology which confines them to a limited area surrounding the store.
For now, the cars are still tracked around the neighborhoods by human-driven vehicles, with monitors to make sure nothing goes haywire. But these "chase cars" should be phased out eventually, an important milestone in the evolution of your robot pizza drivers.
Check out how Nuro's vehicles work:
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