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Astronomers Have Found a Test to Narrow Down What Existed Before The Big Bang

Today our middle-aged Universe looks eerily smooth. Too smooth, in fact.

While a rapid growth spurt in space-time would explain what we see, science needs more than nice ideas. It needs evidence that whittles away contending arguments. We might finally know where to look for some.

A team of physicists from the Centre for Astrophysics | Harvard & Smithsonian (CfA) and Harvard University went back to the drawing board on the early Universe’s evolution to give us a way to help those inflation models stand out from the crowd.

“The current situation for inflation is that it’s such a flexible idea, it cannot be falsified experimentally,” says theoretical physicist Avi Loeb from the CfA.

“No matter what value people measure for some observable attribute, there are always some models of inflation that can explain it.”

We’ve been convinced for some time that our Universe is expanding – its fabric slowly stretching out under the influence of some kind of strange ‘dark’ energy.

If we press rewind on the Universe until it was barely 10-43 seconds old, we arrive at the limit of what our knowledge of physics can handle. Before that moment? Geometry is so nuts, we just don’t know where to start.

Running the calculations backward, we also find the Universe would have had a radius of 10-10 metres at this crucial moment. That sounds tiny, sure, but it’s not tiny enough.

The light echo of the Universe’s first moments are still visible in the form of a cosmic microwave background. Oddly, this background radiation looks surprisingly uniform today.

Thermodynamics makes this observation hard to swallow. Such uniformity means radiation was zipping from one edge of the Universe to the other, balancing out temperature fluctuations. Yet space was expanding too fast for light to keep up.

For such a balancing act to be remotely feasible, the radius of the newborn Universe at that critical moment had to be magnitudes smaller.

This itty-bitty cosmos would have shot through early childhood at an exponential rate, blowing up to the size of a grain of sand in a few ten-thousandths of a second.

The story neatly fits what we observe, but so would other explanations where the Universe didn’t quickly blow apart at the seams.

“In some alternative theories, the size of the Universe contracts. Some do it very slowly, while others do it very fast,” says Harvard physicist Zhong-Zhi Xianyu.

“The attributes people have proposed so far to measure usually have trouble distinguishing between the different theories because they are not directly related to the evolution of the size of the primordial Universe.”

Did time even exist before the Big Bang? Was there some kind of reverse Universe? Everybody is welcome to their pet theory on how our Universe came to look as it does, but only one can be a winner.

To help decide which ones stay and which ones go, the researchers proposed using observable attributes that we can link with discriminating features of inflation-based models.

The challenge is knowing how to interpret such observations as a sequence of events. What’s needed is some sort of standardised cosmic time stamp to tease out relevant steps, some of which could potentially rule out inflation altogether.

“If we imagine all of the information we learned so far about what happened before the Big Bang is in a roll of film frames, then the standard clock tells us how these frames should be played,” says CfA’s Xingang Chen.

The team suggests a mechanism by which quantum fluctuations can hint at sequences of events that are reflected in the patterns of vast cosmic structures.

“These signals will be very subtle to detect,” says Chen.

“The cosmic microwave background radiation is one such place, and the distribution of galaxies is another. We have already started to search for these signals and there are some interesting candidates already, but we need more data.”

Other cosmologists have also suggested searching for hints of our Universe’s hidden past in the swirls of light and matter in the sky.

Some point to possible ‘scars’ left by a previous universe’s black holes on our cosmic microwave background. Others predict we might find signs that the physics-breaking boundary we call the Big Bang never happened.

There are a lot of interesting ideas out there explaining how our Universe evolved. Now we just need to work out which ones we can throw into the ‘nice idea, shame about the facts’ file.

This research has been accepted for publication by Physical Review Letters.

MIKE MCRAE
ScienceAlert

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Science & Technology

NTP nuclear rocket engine will take humans to Mars in just three months

Although the romance of the peaceful atom has subsided since the mid-1960s, the idea of ​​using nuclear reactors for “civilian” purposes is still regularly returned. The new nuclear rocket engine (NRM) will deliver a man to Mars much faster than is possible now.

The danger of cosmic radiation is much more serious than the risk of infection from an accident with such an engine. The most dangerous of all the constraining vectors for projects of sending people to other bodies in the solar system is cosmic radiation. Radiation from our star and galactic rays can seriously damage the health of the mission crew. Therefore, when planning flights to Mars, engineers and scientists try to reduce travel time as much as possible.

One promising way to get to the Red Planet in just three months could be a new NTP engine. Its concept was developed and submitted to NASA by Ultra Safe Nuclear Technologies ( USNC-Tech ) from Seattle, USA. The name of the unit is simply deciphered – Nuclear Thermal Propulsion ( NTP ), that is, “thermal nuclear power plant”. The novelty differs from its previously created or invented counterparts in the most secure design.

A key component of USNC’s development is mid – grade uranium fuel “pellets”. They contain 5% to 20% of the highly reactive isotope U- 235 coated with zirconium carbide ceramics. This degree of enrichment lies roughly halfway between the “civilian” nuclear power plants and the military. The proprietary ceramic coating technology makes the tablets incredibly resistant to mechanical damage and extreme temperatures.

Schematic diagram of a thermal nuclear rocket engine / © Wikipedia |  Tokono
Schematic diagram of a thermal nuclear rocket engine / © Wikipedia | Tokono

The company promises that their fuel elements are significantly superior in these parameters to those currently used at nuclear power plants. As a result, the engine will have a higher specific impulse with a lower degree of uranium enrichment than in earlier versions of NRE. In addition to the flight to Mars, among the goals of the ambitious project are other missions within the solar system. The perspectives of the concept will soon be considered by specialists from NASA and the US Department of Defense ( DoD ). Perhaps departments will even allow its commercial use by private companies.

Theoretically, NRE based on modern technologies can have a specific impulse (SR) seven times higher than that of chemical jet engines. And this is one of the key performance parameters. At the same time, unlike electric and plasma ones, the ID of a nuclear rocket engine is combined with high thrust. One of the limiting factors in the use of NRE, in addition to safety issues, are extremely high temperatures in the reactor core.

The higher the temperature of the gases flowing out of the engine, the more energy they have. And accordingly, they create traction. However, mankind has not yet come up with relatively inexpensive and safe materials that can withstand more than three thousand degrees Celsius without destruction. The solution created by USNC will operate at the limit of modern materials science (3000 ° C) and have a specific impulse twice that of the best liquid-propellant engines.

Tests of the first nuclear jet engine in 1967 / © NASA
Tests of the first nuclear jet engine in 1967 / © NASA

The official press release does not specify which working body will be used in NTP . Usually, in all NRE projects, the reactor core heats hydrogen, less often ammonia. But, since we are talking about a long-term mission, the creators could have chosen some other gas. Keeping liquid hydrogen on board for three months is no easy task. But you still need to invent something for the way back.

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Science & Technology

Scientist Peter Scott-Morgan is set to become “the world’s first complete cyborg”

Scientist and roboticist Peter Scott Morgan, who is using an advanced version of Stephen Hawking's communication system, built by Intel. INTEL

Two years ago scientist Peter Scott-Morgan was diagnosed with motor neuron disease, also known as Lou Gehrig’s disease, and today he is still fighting for a new life, not just for survival.

This October, Dr. Scott-Morgan is on track to become the world’s first full-fledged cyborg, potentially giving him more years of life.

The world’s first complete cyborg

It was in 2017 that Dr. Peter Scott-Morgan (a brilliant robotics writer, scientific writer, and talented speaker) was diagnosed with degenerative motor neuron disease that ultimately paralyzed his entire body except his eyes.

The diagnosis is understandably grim, especially considering that he has only two years to live, but he has not given up the fight.

Teaming up with world-class organizations with expertise in artificial intelligence, Dr. Scott-Morgan is transforming himself into what he calls “the world’s first fully fledged cyborg.”

“And when I say ‘Cyborg’, I mean not just that some kind of payment will be implanted in me, I mean that I will become the most advanced human cybernetic organism ever created on Earth for 13.8 billion years. My body and brain will be irreversibly changed, ”says Dr. Scott-Morgan.

What does it mean to be human

According to Dr. Scott-Morgan, he will become part robot and part living organism. Moreover, the change will not be one-time, but with subsequent updates.

“I have more updates in the process than Microsoft ,” says Dr. Scott-Morgan.

AI-powered creative expression

The cyborg artist is a great example of the power of human-AI collaboration. AI uses the data that make up Peter’s digital portrait ( articles, videos, images, and social media ) and is trained to recognize key ideas, experiences, and images.

Peter will introduce a theme, AI will suggest composition, and Peter will apply images to suggest style and mood. Peter will direct the AI ​​to render a new digital image that none of them could create alone.

A unique blend of AI and human, reflects Peter’s creative and emotional self – a critical aspect of what it means to be human.

Peter 2.0

This October, Dr. Scott-Morgan will undergo what he calls the latest procedure that will transform him into “Complete Cyborg”.

October 9 he tweeted a photo of himself, writing the following:

“This is my last post as Peter 1.0. Tomorrow I will trade my vote for potentially decades of life as we complete the last medical procedure for my transition to Full Cyborg, in the month that I was told statistically I would be dead. I am not dying, I am transforming. ! Oh, how I LOVE science !!! “.

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Science & Technology

Japan has developed an inflatable scooter that weighs practically nothing

The University of Tokyo engineers have developed the Poimo inflatable electric scooter, which is created individually for each owner. It is enough to send your photo to the manufacturers – and a personal optimized model will be assembled for you.

The scooter is designed with a special program for the body size of a particular user and his specific fit. Moreover, each owner is free to make any changes to this model. If he makes any changes to the drawing, the program will automatically redesign the electric bike to maintain its strength, stability and controllability. When the model is finished and approved, it is handed over to the manufacturer.

Scooter Poimo

The scooter consists of seven separate inflatable sections that are constructed from durable fabric and sewn with straight stitch. It remains to add electronic components – in particular, a brushless motor and a lithium-ion battery. 

The finished electric scooter weighs about 9 kg and can travel at speeds up to 6 km / h (that is, slightly faster than a pedestrian). It can work for an hour on one charge.

This is how the current version of Poimo looks like in action:

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