Lifeboat Foundation

The Universe is expanding, and that expansion is speeding up over time. These two facts have been well established through observation, but we don’t know what’s causing that expansion. It seems to be some mysterious, unknown energy that acts like the opposite of gravity.

We call this hypothetical energy “dark energy”, and it’s been calculated to constitute around 72 percent of all the stuff that makes up the Universe. We don’t know what it actually is. But a new experiment has just allowed us to rule out one more thing that it isn’t: a new force.

“This experiment, connecting atomic physics and cosmology, has allowed us to rule out a wide class of models that have been proposed to explain the nature of dark energy, and will enable us to constrain many more dark energy models,’‘said physicist Ed Copeland of the University of Nottingham.

Vast interstellar events where clouds of charged matter hurtle into each other and spew out high-energy particles have now been reproduced in the lab with high fidelity. The work, by MIT researchers and an international team of colleagues, should help resolve longstanding disputes over exactly what takes place in these gigantic shocks.

Many of the largest-scale events, such as the expanding bubble of matter hurtling outward from a supernova, involve a phenomenon called collisionless shock. In these interactions, the clouds of gas or plasma are so rarefied that most of the particles involved actually miss each other, but they nevertheless interact electromagnetically or in other ways to produces visible shock waves and filaments. These high-energy events have so far been difficult to reproduce under laboratory conditions that mirror those in an astrophysical setting, leading to disagreements among physicists as to the mechanisms at work in these astrophysical phenomena.

Now, the researchers have succeeded in reproducing critical conditions of these collisionless shocks in the laboratory, allowing for detailed study of the processes taking place within these giant cosmic smashups. The new findings are described in the journal Physical Review Letters, in a paper by MIT Plasma Science and Fusion Center Senior Research Scientist Chikang Li, five others at MIT, and 14 others around the world.

In the same decade when gravitational waves and a neutron star merger have been observed, astronomers have now observed what they believe to be the first detection of a black hole swallowing a neutron star.

Last Wednesday, gravitational wave detectors in Italy and the US, called LIGO and Virgo, detected telltale ripples in space and time, traced to an event that happened 8,550 million trillion kilometers away from Earth.

Astronomers are analyzing the data from the detection to confirm the size of the two objects that came together to form such cataclysmic ripples, but the event is likely a black hole eating a neutron star.

Cranmer is a member of ATLAS, one of the two general-purpose experiments that, among other things, co-discovered the Higgs boson at the Large Hadron Collider at CERN. He and other CERN researchers recently published a letter in Nature Physics titled “Open is not enough,” which shares lessons learned about providing open data in high-energy physics. The CERN Open Data Portal, which facilitates public access of datasets from CERN experiments, now contains more than two petabytes of information.

It could be said that astronomy, one of the oldest sciences, was one of the first fields to have open data. The open records of Chinese astronomers from 1054 A.D. allowed astronomer Carlo Otto Lampland to identify the Crab Nebula as the remnant of a supernova in 1921. In 1705 Edward Halley used the previous observations of Johannes Kepler and Petrus Apianus—who did their work before Halley was old enough to use a telescope—to deduce the orbit of his eponymous comet.

In science, making data open means making available, free of charge, the observations or other information collected in a scientific study for the purpose of allowing other researchers to examine it for themselves, either to verify it or to conduct new analyses.

Continue reading “With open data, scientists share their work” »

An experiment in the United Kingdom has failed to find evidence of a particle meant to explain most of the universe’s mass. But the search isn’t over.

When cosmologists observe the way the universe expands, they find that present-day theories of matter can’t explain most of the universe’s energy. They call the unknown energy “dark energy,” and theorists have tried to explain it by proposing undiscovered particles and corresponding fields. Experiments have failed to find evidence of such particles, but in physics, that’s not necessarily a bad thing.

By Leah Crane

Some ideas about the quantum world appear to suggest there are many versions of you spread out across many parallel universes. Now, two scientists have formulated a proof that attempts to show this is really true.

The proof involves a fundamental construct in quantum mechanics called Bell’s theorem. This theorem deals with situations where particles interact with each other, become entangled, and then go their separate ways. It is what’s called a “no-go theorem”, one designed to show that some assumption about how the world works is not true.

Mysterious swirling shapes could be leftovers from a black hole.

There is no good evidence that our universe even had a beginning, a startling proposition that means the cosmos could collapse in about 100 billion years.

BIG GULP Gravitational waves may have revealed a black hole in the process of swallowing up a neutron star (illustrated). If confirmed, the event would be the first of its kind ever seen.