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Gravitational waves could reveal how fast the universe is expanding

Scientists believe they’ve discovered a new method to pin down just how fast our universe is expanding over time.

In a new study, a team of researchers from the University of Chicago found that studying the gravitational waves emitted by cosmic collisions could lead to more resolute predictions about how quickly the universe is expanding.

The scientists are so confident in this method that they say they could have a ‘precise measurement’ of the universe’s rate of expansion in roughly five to ten years.

What is the speed of gravity?

According to Einstein’s General Relativity, gravity travels at the speed of light. Proving it is far from simple, though: unlike light, gravity can’t simply be switched on and off, and is also extremely weak.

Over the years, various attempts have been made to measure the speed using studies of astronomical phenomena, such as the time delay of light as it passes through the huge gravitational field of Jupiter. While the results have been broadly in line with Einstein’s prediction, they’ve lacked the precision needed for compelling evidence. That’s now been provided by the celebrated detection of gravitational waves. Analysis of the signals picked up by the two giant LIGO instruments in the US has confirmed that gravity does indeed travel through space at the speed of light.

Extraterrestrials Might Look Like Us, Says Astrobiologist

Maybe they’re not alien doppelgangers — mirror images of us.

But extraterrestrial life—should it exist—might look “eerily similar to the life we see on Earth,” says Charles Cockell, professor of astrobiology at the University of Edinburgh in Scotland.

Indeed, Cockell’s new book (The Equations of Life: How Physics Shapes Evolution, Basic Books, 352 pages) suggests a “universal biology.” Alien adaptations, significantly resembling terrestrial life—from humanoids to hummingbirds—may have emerged on billions of worlds.

World’s fastest camera freezes time at 10 trillion frames per second

What happens when a new technology is so precise that it operates on a scale beyond our characterization capabilities? For example, the lasers used at INRS produce ultrashort pulses in the femtosecond range (10-15 s), which is far too short to visualize. Although some measurements are possible, nothing beats a clear image, says INRS professor and ultrafast imaging specialist Jinyang Liang. He and his colleagues, led by Caltech’s Lihong Wang, have developed what they call T-CUP: the world’s fastest camera, capable of capturing 10 trillion (1013) frames per second (Fig. 1). This new camera literally makes it possible to freeze time to see phenomena—and even light—in extremely slow motion.

In recent years, the junction between innovations in non-linear optics and imaging has opened the door for new and highly efficient methods for microscopic analysis of dynamic phenomena in biology and physics. But harnessing the potential of these methods requires a way to record in at a very short temporal resolution—in a single exposure.

Using current imaging techniques, measurements taken with must be repeated many times, which is appropriate for some types of inert samples, but impossible for other more fragile ones. For example, laser-engraved glass can tolerate only a single laser pulse, leaving less than a picosecond to capture the results. In such a case, the imaging technique must be able to capture the entire process in real time.

Some Physicists Think Time May Be Slowing Down

The universe is expanding at an ever-accelerating rate. At least, that’s what the vast majority of scientists would have you believe. But according to a team of Spanish physicists, it may not be the expansion of the universe that’s changing rate, but time itself. Time might be slowing down, and that means that it could eventually stop altogether.

The Insane Physics of Airbags

I can imagine the meeting: A dozen engineers are gathered around a conference table to discuss automobile safety. How can we protect people during a car crash? We have already added seat belts and crumple zones to cars. Is there anything else we can include? One attendee reluctantly raises their hand with a suggestion: “How about we add an explosive in the steering wheel?”

Meghnad Saha the physicist also known for Planning Commission and providing national calendar

New Delhi, Oct 6: There are many unsung and forgotten heroes that India has in abundance. One such man whose 125th birth anniversary falls today is Meghnad Saha who was not only nominated for the Nobel Prize in Physics more than once but was also elected to the first Lok Sabha in 1952 as an independent candidate defeating the Congress nominee Prabhu Dayal Himatsingka. But more interestingly he was the chairperson of Calender Reforms Committee set up in 1952.

No one can forget the role of Planning Commission of India in the growth trajectory of the country which was actually conceived by Subhash Chandra Bose at the Haripura Congress in 1938. Bose as a president proposed it as National Planning Committee in which Saha had shown very keen interest.

Also Read Denis Mukwege, Nadia Murad awarded 2018 Nobel Peace Prize.

A new brain-inspired architecture could improve how computers handle data and advance AI

General interest.


IBM researchers are developing a new computer architecture, better equipped to handle increased data loads from artificial intelligence. Their designs draw on concepts from the human brain and significantly outperform conventional computers in comparative studies. They report on their recent findings in the Journal of Applied Physics.

Today’s computers are built on the von Neumann architecture, developed in the 1940s. Von Neumann computing systems feature a central processer that executes logic and arithmetic, a memory unit, storage, and input and output devices. Unlike the stovepipe components in conventional computers, the authors propose that brain-inspired computers could have coexisting processing and memory units.

Abu Sebastian, an author on the paper, explained that executing certain in the computer’s memory would increase the system’s efficiency and save energy.