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The Science & Technology Thread

Postby Buc2 » Tue Feb 10, 2015 9:09 am

No Big Bang? Quantum equation predicts universe has no beginning

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This is an artist's concept of the metric expansion of space, where space (including hypothetical non-observable portions of the universe) is represented at each time by the circular sections. Note on the left the dramatic expansion (not to scale) occurring in the inflationary epoch, and at the center the expansion acceleration. The scheme is decorated with WMAP images on the left and with the representation of stars at the appropriate level of development. Credit: NASA

(Phys.org) —The universe may have existed forever, according to a new model that applies quantum correction terms to complement Einstein's theory of general relativity. The model may also account for dark matter and dark energy, resolving multiple problems at once.

The widely accepted age of the universe, as estimated by general relativity, is 13.8 billion years. In the beginning, everything in existence is thought to have occupied a single infinitely dense point, or singularity. Only after this point began to expand in a "Big Bang" did the universe officially begin.

Although the Big Bang singularity arises directly and unavoidably from the mathematics of general relativity, some scientists see it as problematic because the math can explain only what happened immediately after—not at or before—the singularity.

"The Big Bang singularity is the most serious problem of general relativity because the laws of physics appear to break down there," Ahmed Farag Ali at Benha University and the Zewail City of Science and Technology, both in Egypt, told Phys.org.

Ali and coauthor Saurya Das at the University of Lethbridge in Alberta, Canada, have shown in a paper published in Physics Letters B that the Big Bang singularity can be resolved by their new model in which the universe has no beginning and no end.

Old ideas revisited

The physicists emphasize that their quantum correction terms are not applied ad hoc in an attempt to specifically eliminate the Big Bang singularity. Their work is based on ideas by the theoretical physicist David Bohm, who is also known for his contributions to the philosophy of physics. Starting in the 1950s, Bohm explored replacing classical geodesics (the shortest path between two points on a curved surface) with quantum trajectories.

In their paper, Ali and Das applied these Bohmian trajectories to an equation developed in the 1950s by physicist Amal Kumar Raychaudhuri at Presidency University in Kolkata, India. Raychaudhuri was also Das's teacher when he was an undergraduate student of that institution in the '90s.

Using the quantum-corrected Raychaudhuri equation, Ali and Das derived quantum-corrected Friedmann equations, which describe the expansion and evolution of universe (including the Big Bang) within the context of general relativity. Although it's not a true theory of quantum gravity, the model does contain elements from both quantum theory and general relativity. Ali and Das also expect their results to hold even if and when a full theory of quantum gravity is formulated.

No singularities nor dark stuff

In addition to not predicting a Big Bang singularity, the new model does not predict a "big crunch" singularity, either. In general relativity, one possible fate of the universe is that it starts to shrink until it collapses in on itself in a big crunch and becomes an infinitely dense point once again.

Ali and Das explain in their paper that their model avoids singularities because of a key difference between classical geodesics and Bohmian trajectories. Classical geodesics eventually cross each other, and the points at which they converge are singularities. In contrast, Bohmian trajectories never cross each other, so singularities do not appear in the equations.

In cosmological terms, the scientists explain that the quantum corrections can be thought of as a cosmological constant term (without the need for dark energy) and a radiation term. These terms keep the universe at a finite size, and therefore give it an infinite age. The terms also make predictions that agree closely with current observations of the cosmological constant and density of the universe.

New gravity particle

In physical terms, the model describes the universe as being filled with a quantum fluid. The scientists propose that this fluid might be composed of gravitons—hypothetical massless particles that mediate the force of gravity. If they exist, gravitons are thought to play a key role in a theory of quantum gravity.

In a related paper, Das and another collaborator, Rajat Bhaduri of McMaster University, Canada, have lent further credence to this model. They show that gravitons can form a Bose-Einstein condensate (named after Einstein and another Indian physicist, Satyendranath Bose) at temperatures that were present in the universe at all epochs.

Motivated by the model's potential to resolve the Big Bang singularity and account for dark matter and dark energy, the physicists plan to analyze their model more rigorously in the future. Their future work includes redoing their study while taking into account small inhomogeneous and anisotropic perturbations, but they do not expect small perturbations to significantly affect the results.

"It is satisfying to note that such straightforward corrections can potentially resolve so many issues at once," Das said.
Last edited by Buc2 on Wed Jun 08, 2016 12:54 pm, edited 1 time in total.
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Re: The Science Thread

Postby Rocker » Tue Feb 10, 2015 10:01 am

I stopped at graviton. No way I can take a scientific paper seriously that includes carnival rides. Frikkin' noobs.
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Re: The Science Thread

Postby paco74 » Tue Feb 10, 2015 11:51 am

Love. This. Stuff.
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Re: The Science Thread

Postby Buc2 » Tue Feb 10, 2015 12:33 pm

Me too, paco. Between history & science, I'd have a hard time choosing my favorite subject. Science probably holds a slight edge.
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Re: The Science Thread

Postby Buc2 » Fri Feb 27, 2015 9:43 am

'Big Brain' Gene Found in Humans, Not Chimps

A single gene may have paved the way for the rise of human intelligence by dramatically increasing the number of brain cells found in a key brain region.

This gene seems to be uniquely human: It is found in modern-day humans, Neanderthals and another branch of extinct humans called Denisovans, but not in chimpanzees.

By allowing the brain region called the neocortex to contain many more neurons, the tiny snippet of DNA may have laid the foundation for the human brain's massive expansion.

Click on link above if you want to read the entire article.


All which leads to the next obvious step...

Then the team inserted and expressed (turned on) this DNA snippet in the brains of mice. Though mice normally have a tiny, smooth neocortex, the mice with the gene insertion grew what looked like larger neocortices; these amped-up brain regions contained loads of neurons and some even began forming the characteristic folds, or convolutions, found in the human brain, a geometry that packs a lot of dense brain tissue into a small amount of space. (The researchers did not check to see if the mice actually got smarter, though that is a potential avenue of future research, Florio said).
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Re: The Science Thread

Postby Mother Ayahuasca » Fri Feb 27, 2015 10:39 am

The widely accepted age of the universe, as estimated by general relativity, is 13.8 billion years


That's weird because I was always told that is was 6,000 year old....
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Re: The Science Thread

Postby Buc2 » Fri Feb 27, 2015 11:18 am

Next, they will try it on apes and then...

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Re: The Science Thread

Postby Deuce » Fri Feb 27, 2015 1:26 pm

I think the Big Bang is accepted just because it's easy for us to comprehend. I mean, the universe has existed forever? I can't fathom how that works.
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Re: The Science Thread

Postby Buc2 » Fri Feb 27, 2015 2:26 pm

Deuce wrote:I think the Big Bang is accepted just because it's easy for us to comprehend. I mean, the universe has existed forever? I can't fathom how that works.


So where did the ball of energy that burst into the Big Bang come from? Was it always just there? How's THAT possible? God, you say? So where did God come from? He was always there? How's THAT possible?
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Re: The Science Thread

Postby deltbucs » Fri Feb 27, 2015 3:09 pm

Buc2 wrote:
Deuce wrote:I think the Big Bang is accepted just because it's easy for us to comprehend. I mean, the universe has existed forever? I can't fathom how that works.


So where did the ball of energy that burst into the Big Bang come from? Was it always just there? How's THAT possible? God, you say? So where did God come from? He was always there? How's THAT possible?

I've heard 2 theories on the Big Bang that I found interesting. First of all, I don't think it was the beginning of the universe (or multiverse). 1) I've heard a theory that the universe just goes in a cycle of expanding and contracting back to a singularity that was pretty interesting. 2) This universe is like the other side of a black hole from another universe. Either way, I think a black hole is where the matter came/expanded from.

Love the thread, BTW.
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Re: The Science Thread

Postby Deuce » Fri Feb 27, 2015 3:22 pm

Buc2 wrote:
Deuce wrote:I think the Big Bang is accepted just because it's easy for us to comprehend. I mean, the universe has existed forever? I can't fathom how that works.


So where did the ball of energy that burst into the Big Bang come from? Was it always just there? How's THAT possible? God, you say? So where did God come from? He was always there? How's THAT possible?


You pretty much proved my point. It's also why religion is generally accepted. We can't comprehend not existing, so obviously something happens to our "soul" when we die.
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Re: The Science Thread

Postby Brazen331 » Fri Mar 06, 2015 5:07 am

Seems like this hearkens back to the steady-state theory which I thought all modern physicists rejected. I love how quantum theory relates to all this: how at the subatomic level relativity and Einstein are basically meaningless. One theory that I love postulates that the reason why particles like electrons never have any fixed location is because they are flitting in and out of a countless number of Universes, which may mean that there is a Universe out there where Winstonmagic makes intelligent posts, and another Universe where Bootz has less posts than me.
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Re: The Science Thread

Postby Buc2 » Fri Mar 06, 2015 8:33 am

Brazen331 wrote:Seems like this hearkens back to the steady-state theory which I thought all modern physicists rejected. I love how quantum theory relates to all this: how at the subatomic level relativity and Einstein are basically meaningless. One theory that I love postulates that the reason why particles like electrons never have any fixed location is because they are flitting in and out of a countless number of Universes, which may mean that there is a Universe out there where Winstonmagic makes intelligent posts, and another Universe where Bootz has less posts than me.


I was with you until your last sentence. No way, in ANY universe, would Winstonmagic be able to make intelligent posts. :D
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Re: The Science Thread

Postby deltbucs » Fri Mar 06, 2015 9:24 am

Brazen331 wrote:Seems like this hearkens back to the steady-state theory which I thought all modern physicists rejected. I love how quantum theory relates to all this: how at the subatomic level relativity and Einstein are basically meaningless. One theory that I love postulates that the reason why particles like electrons never have any fixed location is because they are flitting in and out of a countless number of Universes, which may mean that there is a Universe out there where Winstonmagic makes intelligent posts, and another Universe where Bootz has less posts than me.

What about quantum entanglement? Whenever WinstonMagic makes a post on this board, someone else makes the exact same posts over in Europe on the ManU board. Ever think of that?
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Re: The Science Thread

Postby Zarniwoop » Fri Mar 06, 2015 9:28 am

All anyone ever needs to know about science, the beginning of the universe and all the rest of this kind of stuff is written down in a set of holy books....everyone should be required to read and study them. They are divinely inspired.








































































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Re: The Science Thread

Postby The Outsider » Fri Mar 06, 2015 11:22 am

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Re: The Science Thread

Postby Wenchy » Fri Mar 06, 2015 3:48 pm

Outie has been blinded.
Keep on keeping on, science geeks. I love it.
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Re: The Science Thread

Postby BigIrv9 » Fri Mar 06, 2015 9:17 pm

A philosopher's take on Science v Religion:

https://m.youtube.com/watch?v=AJu0oYvi-cY&sns=em
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Re: The Science Thread

Postby NoAlibi » Sat Mar 07, 2015 11:45 pm

I feel a poem coming on.. I feel it from the bowels of pennsylvania..
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Re: The Science Thread

Postby Corsair » Sun Mar 08, 2015 10:50 pm

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Re: The Science Thread

Postby deltbucs » Fri Mar 13, 2015 3:02 pm

The LHC is finally set to fire back up this month!

http://www.iflscience.com/physics/what- ... n-collider
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Re: The Science Thread

Postby Buc2 » Fri Apr 03, 2015 12:01 pm

The experts think we're ready and the only thing that could stand in the way is politics. I would like to live long enough to see it happen.

Manned Mars Mission Plan: Astronauts Could Orbit by 2033, Land by 2039

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At a news conference this morning (April 2), representatives of The Planetary Society presented the results of a workshop organized to discuss the feasibility and cost of a crewed mission to orbit the Martian moon Phobos in 2033, leading up to a crewed landing on the Red Planet in 2039. They concluded that such a plan could indeed fit within NASA's human space exploration budget.

"We believe we now have an example of a long-term, cost-constrained, executable humans-to-Mars program," Scott Hubbard, a professor in the Stanford University Department of Aeronautics and Astronautics and a member of The Planetary Society's board of directors, said in a statement. [5 Manned Mission to Mars Ideas]

The Planetary Society is the largest nongovernmental space advocacy organization in the world, according to its website. In addition to Hubbard, two other science experts spoke at the event: Planetary Society CEO (and former TV "Science Guy") Bill Nye and John Logsdon, a professor emeritus at The George Washington University Space Policy Institute who is also a member of The Planetary Society's board of directors.

The "Humans Orbiting Mars" workshop took place from March 31 to April 1 in Washington, D.C. The workshop's 70 attendees discussed the technical feasibility, affordability and benefits of a proposed schedule to get humans into orbit around Mars and eventually onto the planet's surface. That detailed plan was not created by The Planetary Society, but rather was proposed in a separate report co-created by NASA's Jet Propulsion Laboratory.

In a statement, the society said the attendees of the workshop "reached a consensus" on a series of key points, including that an orbital mission would be required prior to a crewed mission to the surface of Mars, and an independent cost estimate showed that the program would fit into the NASA budget, assuming the agency "ends its lead role in the International Space Station."

The panel emphasized the 2033 orbital mission as the crucial first step of the plan, comparing it to NASA's Apollo 8 mission, which took astronauts into orbit around the moon before humans landed on the satellite's surface.

The Phobos orbital mission would last approximately 30 months, with nine months of travel each way and 12 months in orbit, the panelists said. Crewmembers would be able to study Phobos and Deimos, Mars' other moon, and potentially teleoperate rovers on the Martian surface. The panel said the current plan would use an Orion spacecraft to move crewmembers from Earth into orbit and back down.

When asked what potential roadblocks this Mars program might face, all of the panelists stated that the largest hurdles were political, not technical.

"I'm not saying the technical challenges aren't extraordinary and very, very difficult," Nye said. "And it's going to take a lot of thoughtful engineers and scientists giving it a lot of thought and science. But the real problem is politics — or the real opportunity is politics."

Logsdon said he thinks a decision on whether to adopt the plan is "an issue for the next president."

Hubbard said that, in the past, Mars missions may have been limited by technological or scientific challenges, but that no longer appears to be the case.

"In the past, when the question of humans to Mars came up, I would typically cite a number of major hurdles: biomedical, launch systems and so forth," he said. "And as of today, I think that those risks have either been reduced or you know how to minimize them, and so I am at the same place that John [Logsdon] and Bill [Nye] [are], that I think the issue now is […] political will."
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Re: The Science Thread

Postby Buc2 » Tue Apr 14, 2015 3:46 pm

Falcon 9 launched a few minutes ago on a mission to carry supplies and science to ISS. The hope of recovering, intact, the 1st stage rocket was, however, unsuccessful again. They have a bunch more launches scheduled this year and will keep trying to recover the stage on the floating ocean platform.

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UPDATE: The rocket is away! The next big step is attempting recovery of stage one of the Falcon 9 rocket.

UPDATE 2: Dragon has successfully separated from the second stage Falcon 9 rocket.

UPDATE 3: The webcast has ended, but we’re still awaiting word regarding the landing barge attempt of the reusable first-stage rocket.

UPDATE 4: SpaceX CEO Elon Musk shared the following, indicating that the attempted recovery of the reusable stage one rocket failed – the rocket landed on the autonomous barge, but it impacted too hard to survive to be used again. Still, the attempt will likely provide lots of useful data to inform the next try.
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Re: The Science Thread

Postby Buc2 » Wed Apr 15, 2015 9:40 am

A video of the rocket landing attempt is out...

No embed available.

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Re: The Science Thread

Postby Buc2 » Fri Apr 17, 2015 8:02 am

New footage supposedly taken from a GoPro camera mounted on the landing barge.



Tuesday saw SpaceX come agonizingly close to landing its reusable Falcon 9 rocket on a barge at sea, and the released footage (below) made the failed attempt seem somehow serene; the rocket drifts into view and floats onto its target like a sycamore seed before toppling over in slow motion.

But in this unverified new video (above), which appeared on Reddit and allegedly came from a GoPro camera mounted on the barge itself, the explosive reality of the events are thrown into sharp relief. You can see how the rocket overcompensates for its off-balance approach before meeting a fiery end as it comes down on the barge. SpaceX is making big advances with its Falcon 9 rocket, but this video gives a better idea of just how complex the physics are that Elon Musk and company have to wrestle with.

Gwynne Shotwell, SpaceX's president and COO, told DefenseNews Wednesday that the company's next attempt is likely to occur on land in order to give the target extra stability.

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Re: The Science Thread

Postby paco74 » Fri Apr 17, 2015 8:26 am

I'm curious about something with this approach on recovery. Why is it necessary to "land" the damned thing? Why not have it come down just as it did but instead of a pad, have it land inside a large floating circle which is supporting a large net well below the surface of the water. Cut the engines and have it gently caught from underneath. Sure the system might get water penetration but I'm sure these engineerings are savvy enough to protect the vital electronics. Worst case, they have to replace electrical parts but they still have a fully intact rocket.

Am I nuts or is the solution just that simple they can't see it?
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Re: The Science Thread

Postby Buc2 » Fri Apr 17, 2015 8:30 am

Good question. I have no idea. If they could let it just land in the ocean, then simply using parachutes would be the answer, wouldn't it? I'm not sure why there is a need to "save it" from the water. If water is the problem, then why not just parachute it down over the desert then?
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Re: The Science Thread

Postby paco74 » Fri Apr 17, 2015 8:45 am

Exactly. It sounds like they are out thinking themselves. Sure it would look cool to do what they are trying to do, but is it practical or even necessary? I can imagine not.

To me, their problem came when the rocket got close to the pad. The pad is not stable because of the rolling waters. Any tilt on the barge will cause equal and opposite forces to be developed in the x and y axes causing the rocket, which is trying to land directly down the z-axis, to tilt.
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Re: The Science Thread

Postby Buc2 » Fri Apr 17, 2015 11:40 am

I tried to find something explaining why they want to do the recovery on an ocean barge instead of land, but haven't found anything. The only thing I can think of, land isn't a good option due to proximity issues.
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Re: The Science Thread

Postby Shadowhawk » Fri Apr 17, 2015 1:21 pm

I think they are planning on landing on land. I think they need to test the concept first:


SpaceX signed a five-year lease for Launch Complex 13 on 10 February 2015, in order to use the area to land reusable launch vehicles at the pad.[1][1][7] It intends to convert the old Atlas launch pad into a set of five discrete landing pads, one large primary pad with four smaller alternate pads surrounding it.[1][8][9]

As of March 2, 2015, the Air Force's sign for LC-13 was replaced with a sign identifying it as Landing Complex 1.[10][11][12][13]

SpaceX has also signed a lease for a west coast landing pad at Vandenberg AFB Space Launch Complex 4.[14]
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