Get a free month of Curiosity Stream: https://curiositystream.com/isaacarthur. The Universe is immense. Does it have an edge out beyond the Cosmological Event Horizon? Or in time, before the Big Bang? Or in higher dimensions like Hyperspace?
Sign up for a Curiosity Stream subscription and also get a free Nebula subscription (the streaming platform built by creators) here: https://curiositystream.com/isaacarthur. In the future humanity may build enormous structures, feats of mega-engineering that may rival planets or even be of greater scope. This episode catalogs roughly 100 major types of Megastructure, from those that are cities in space to those that rival galaxies.
Credits: The Megastructure Compendium. Science & Futurism with Isaac Arthur. Episode 346, June 9, 2022 Written & Produced by Isaac Arthur. Narrated by Isaac Arthur & Sarah Fowler Arthur.
A year ago, astronomers discovered a powerful gamma-ray burst (GRB) lasting nearly two minutes, dubbed GRB 211211A. Now, that unusual event is upending the long-standing assumption that longer GRBs are the distinctive signature of a massive star going supernova. Instead, two independent teams of scientists identified the source as a so-called “kilonova,” triggered by the merger of two neutron stars, according to a new paper published in the journal Nature. Because neutron star mergers were assumed to only produce short GRBs, the discovery of a hybrid event involving a kilonova with a long GRB is quite surprising.
“This detection breaks our standard idea of gamma-ray bursts,” said co-author Eve Chase, a postdoc at Los Alamos National Laboratory. “We can no longer assume that all short-duration bursts come from neutron-star mergers, while long-duration bursts come from supernovae. We now realize that gamma-ray bursts are much harder to classify. This detection pushes our understanding of gamma-ray bursts to the limits.”
As we’ve reported previously, gamma-ray bursts are extremely high-energy explosions in distant galaxies lasting between mere milliseconds to several hours. The first gamma-ray bursts were observed in the late 1960s, thanks to the launching of the Vela satellites by the US. They were meant to detect telltale gamma-ray signatures of nuclear weapons tests in the wake of the 1963 Nuclear Test Ban Treaty with the Soviet Union. The US feared that the Soviets were conducting secret nuclear tests, violating the treaty. In July 1967, two of those satellites picked up a flash of gamma radiation that was clearly not the signature of a nuclear weapons test.
Did you hear that #physicists simulated a baby #wormhole in a lab? Well, it’s even more true that #StringTheory and #ExtraDimensions were discovered in the ’60s. Think I’m joking? I’m not. To learn what’s true/false in the wormhole story, read this first.
This research could potentially lead to a better understanding of the galaxy and its many mysteries.
It’s a cosmic riddle: How can galaxies remain together when all the matter we observe isn’t enough to keep them intact? Scientists believe an invisible force must beat play, something so mysterious they named it “dark matter” because of its lack of visibility.
This mysterious presence accounts for nearly three times more than what we can observe — a startling 27% of all existence! The mysterious dark matter is a profound mystery to scientists, its existence making up nearly one-third of the universe’s energy and mass yet remaining elusive due to its ability to avoid detection.
IStock / agsandrew.
This mysterious presence accounts for nearly three times more than what we can observe – a startling 27% of all existence! The mysterious dark matter is a profound mystery to scientists, its existence making up nearly one-third of the universe’s energy and mass yet remaining elusive due to its ability to avoid detection. Dark matter particles move relatively slowly, which explains why it has been mostly concealed from view until now.
This type of gamma ray burst (GRB) is thought to occur when a massive star explodes in a supernova, leaving behind a black hole. The explosion creates an extraordinary jet of light which makes up the GRB itself, and then the supernova causes a dimmer afterglow. This particular GRB appears so bright partially because it is about 2.4 billion light years away from Earth, making it one of the closest GRBs ever spotted in addition to being the brightest.
“If we look at all of the gamma ray bursts that have been detected, this one stands apart,” says Jillian Rastinejad at Northwestern University in Illinois. “Informally, we’ve been calling it the BOAT – the brightest of all time.” She and her colleagues calculated that a GRB this bright is expected to occur only once every thousand years or so.
Astronomers have spotted a strange blast of gamma radiation from space that defies categorisation, and it may mean a gap in our understanding of how black holes form.
Gas clouds across the universe are known to absorb the light produced by distant massive celestial objects, known as quasars. This light manifests as the so-called Lyman alpha forest, a dense structure composed of absorption lines that can be observed using spectroscopy tools.
Over the past decades, astrophysicists have been assessing the value of these absorption lines as a tool to better understand the universe and the relationships between cosmological objects. The Lyman alpha forest could also potentially aid the ongoing search for dark matter, offering an additional tool to test theoretical predictions and models.
Researchers at University of Nottingham, Tel-Aviv University, New York University, and the Institute for Fundamental Physics of the Universe in Trieste have recently compared low-redshift Lyman alpha forest observations to hydrodynamical simulations of the intergalactic medium and dark matter made up of dark photons, a renowned dark matter candidate.
In 1916, Einstein finished his Theory of General Relativity, which describes how gravitational forces alter the curvature of spacetime. Among other things, this theory predicted that the Universe is expanding, which was confirmed by the observations of Edwin Hubble in 1929. Since then, astronomers have looked farther into space (and hence, back in time) to measure how fast the Universe is expanding – aka. the Hubble Constant. These measurements have become increasingly accurate thanks to the discovery of the Cosmic Microwave Background (CMB) and observatories like the Hubble Space Telescope.
Astronomers have traditionally done this in two ways: directly measuring it locally (using variable stars and supernovae) and indirectly based on redshift measurements of the CMB and cosmological models. Unfortunately, these two methods have produced different values over the past decade. As a result, astronomers have been looking for a possible solution to this problem, known as the “Hubble Tension.” According to a new paper by a team of astrophysicists, the existence of “Early Dark Energy” may be the solution cosmologists have been looking for.
The big bang is one of the most fascinating topics you can bring up when conversing with scientists and astronomers. This is because the theory talks about how the whole universe started in the first place. However, the event that led to the big bang is one thing that is being argued among scientists today.
For this reason, the James Webb Telescope was called in to make some findings about the big bang. The JWST found something quite alright, but it wasn’t something the scientist had prepared their minds for. What did the James Webb Telescope discover, and in what way would it affect the Big Bang Theory?
Join us as we explore the James Webb telescope’s terrifying discovery before the big bang.
It all began when an astronomer sighted a discovery made by the James Webb Telescope. Astronomer Rohan Naidu was at home with his girlfriend when he discovered the galaxy that almost broke cosmology. He was inspecting some of the images the James Webb Telescope sent earlier when one of the images caught his attention. The telescope had identified an object that Naidu recognized as mysteriously huge. It dates back to the big bang era, making it older than any galaxy we once knew in science. It was a shocking discovery for him, as he called his girlfriend to observe the most distant starlight too. He was praised for this discovery by his team, and then they got to work. A few days later, Naidu and his team published a paper on the discovered galaxy called “GLASS-z13.” It was a discovery that had the whole world of science come to a standstill, as no one expected such a discovery to be made by the James Webb Telescope.
The James Webb Telescope made this ancient galaxy discovery just a few weeks after it went into operation. It was a huge achievement because if such a discovery could be made a few weeks into the telescope’s launch, what next would it discover? The JWST, the most powerful telescope currently in use by scientists and astronomers and the Hubble Space Telescope’s successor, was built to make us understand our universe better, and it is already achieving that feat. The telescope is 1.5 million kilometers away from earthly interference, where it orbits the sun. It is equipped with a sunshade about the size of a tennis court, with huge segmented mirrors and very sensitive tools designed to detect details about the universe and its entirety that have never been explored.
