Menu

Blog

Archive for the ‘cosmology’ category: Page 250

Mar 29, 2021

The Very First Structures in the Universe: Astrophysicists Simulate Microscopic Clusters From the Big Bang

Posted by in categories: computing, cosmology, particle physics

The very first moments of the Universe can be reconstructed mathematically even though they cannot be observed directly. Physicists from the Universities of Göttingen and Auckland (New Zealand) have greatly improved the ability of complex computer simulations to describe this early epoch. They discovered that a complex network of structures can form in the first trillionth of a second after the Big Bang. The behavior of these objects mimics the distribution of galaxies in today’s Universe. In contrast to today, however, these primordial structures are microscopically small. Typical clumps have masses of only a few grams and fit into volumes much smaller than present-day elementary particles. The results of the study have been published in the journal Physical Review D.

Mar 28, 2021

Astronomers’ Polarized Image Shows Magnetic Fields at the Edge of M87’s Black Hole

Posted by in category: cosmology

MIT Haystack Observatory is one of the 13 stakeholder institutions that constitute the Event Horizon Telescope (EHT) collaboration, which produced the first-ever image of a black hole. The EHT revealed today a new view of the massive object at the center of the M87 galaxy: how it looks in polarized light. This is the first time astronomers have been able to measure polarization, a signature of magnetic fields, this close to the edge of a black hole. The observations are key to explaining how the M87 galaxy, located 55 million light-years away, is able to launch energetic jets from its core.

Haystack Research Scientist Vincent Fish says “Hundreds of people around the world in the EHT collaboration, including scientists and engineers at Haystack, have worked very hard to investigate the role of magnetic fields in shaping jets around black holes. Can magnetic fields build up and dominate over the intense pull of gravity? Our data provide an answer.”

Mar 27, 2021

Tantalizing Evidence: Is the Nearest Star Cluster to the Sun Being Destroyed?

Posted by in categories: cosmology, mapping, particle physics

Data from ESA’s Gaia star mapping satellite have revealed tantalizing evidence that the nearest star cluster to the Sun is being disrupted by the gravitational influence of a massive but unseen structure in our galaxy.

If true, this might provide evidence for a suspected population of ‘dark matter sub-halos’. These invisible clouds of particles are thought to be relics from the formation of the Milky Way, and are now spread across the galaxy, making up an invisible substructure that exerts a noticeable gravitational influence on anything that drifts too close.

Continue reading “Tantalizing Evidence: Is the Nearest Star Cluster to the Sun Being Destroyed?” »

Mar 26, 2021

Vera Rubin, astronomer extraordinaire — a new biography

Posted by in category: cosmology

She confirmed dark matter, probed spiral galaxies and fought inequality.

Mar 25, 2021

A missing part of the universe has been found

Posted by in category: cosmology

About half of the relatively small portion of the universe that is not dark matter or energy is in fact a mixture of gases that may connect galaxies in a kind of loose cosmic web, according to new research illuminating vast areas that were previously unknown.

Until now, this sizable chunk of “baryonic matter,” which makes up 5% of the universe, had been unaccounted for. Researchers from institutions in Spain and the Argonne National Laboratory in Illinois detailed their findings in a study published March 25 in Monthly Notices of the Royal Astronomical Society.

While the other 95% of the universe is made up of dark matter and dark energy, baryonic matter comprises stars, planets, galaxies and everything they contain, including living things. Astronomers knew it was there, but didn’t know if it was more stars, planets or anything else that wasn’t dark matter or energy.

Mar 25, 2021

Episode 43 — What Future And Final Galaxy Surveys Will Teach Us About The Cosmos

Posted by in categories: cosmology, futurism

Great new episode with NASA cosmologist Jason Rhodes who discusses everything from the earliest galaxy surveys to dark matter and the cosmic web.


Jason Rhodes, a cosmologist at NASA’s Jet Propulsion Laboratory in Pasadena, and the JPL Roman Space Telescope Project Scientist, discusses a proposed galaxy survey to end all galaxy surveys. One that would wring as much information out of our universe’s trillion or so galaxies across cosmic time as humanly possible. Astronomers are still at least half a century off from this final galaxy census, but the hope is that it will give cosmologists most of the answers they need about the makeup and structure of the universe.

Continue reading “Episode 43 --- What Future And Final Galaxy Surveys Will Teach Us About The Cosmos” »

Mar 24, 2021

What is dark matter? An answer may come from the most accurate clocks in the world

Posted by in category: cosmology

These clocks could, in theory at least, keep time so accurately they’d gain or lose less than a second over the entire age of the universe.

Mar 24, 2021

Piercing Through a Galaxy’s Dusty Core to Uncover the Secrets of an Active Supermassive Black Hole

Posted by in category: cosmology

Researchers using NASA’s upcoming James Webb Space Telescope will map and model the core of nearby galaxy Centaurus A.

As technology has improved over the centuries, so have astronomers’ observations of nearby galaxy Centaurus A. They have peeled back its layers like an onion to discover that its wobbly shape is the result of two galaxies that merged more than 100 million years ago. It also has an active supermassive black hole, known as an active galactic nucleus, at its heart that periodically sends out twin jets. Despite these advancements, Centaurus A’s dusty core is still quite mysterious. Webb’s high-resolution infrared data will allow a research team to very precisely reveal all that lies at the center.

Mar 24, 2021

Cosmic Inflation Was Likely Not A One-Off Event, Says Astronomer

Posted by in categories: cosmology, materials

“Whooshes of creation” may be producing multiverses at this moment, says astronomer.


The cosmic inflation credited with creating the homogeneous universe which we now enjoy was likely not a one-off event, University of California, Berkeley astronomer Alexei Filippenko, told me. In fact, these ‘whooshes of creation’ may be producing multiverses even at this moment, says Filippenko.

The idea of an exponential, faster-than-light expansion of the early universe, was first put forth by MIT astrophysicist Alan Guth in 1981. And today, Inflation theory is used to explain the Cosmos’ current size, expansion, homogeneity and the fact that it appears to be geometrically flat, I noted in a 2011 issue of Astronomy magazine.

Continue reading “Cosmic Inflation Was Likely Not A One-Off Event, Says Astronomer” »

Mar 20, 2021

An All-Sky X-Ray Survey Finds the Biggest Supernova Remnant Ever Seen

Posted by in categories: cosmology, mathematics

Our sky is missing supernovas. Stars live for millions or billions of years. But given the sheer number of stars in the Milky Way, we should still expect these cataclysmic stellar deaths every 30–50 years. Few of those explosions will be within naked-eye-range of Earth. Nova is from the Latin meaning “new”. Over the last 2000 years, humans have seen about seven “new” stars appear in the sky – some bright enough to be seen during the day – until they faded after the initial explosion. While we haven’t seen a new star appear in the sky for over 400 years, we can see the aftermath with telescopes – supernova remnants (SNRs) – the hot expanding gases of stellar explosions. SNRs are visible up to a 150000 years before fading into the Galaxy. So, doing the math, there should be about 1200 visible SNRs in our sky but we’ve only managed to find about 300. That was until “Hoinga” was recently discovered. Named after the hometown of first author Scientist Werner Becker, whose research team found the SNR using the eROSITA All-Sky X-ray survey, Hoinga is one of the largest SNRs ever seen.

Hoinga is big. Really big. The SNR spans 4 degrees of the sky – eight times wider than the Full Moon. The obvious question – how could astronomers not have already found something THAT enormous? Hoinga is not where we typically are looking for supernova. Most of our SNR searches are focused on the plane of the Galaxy toward the Milky Way’s core where we’d expect to find the densest concentration of older and exploded stars. But Hoinga was found at high latitudes off the plane of the Galaxy.

Furthermore, Hoinga hides in the sky because it’s so large. At this scale, the SNR is difficult to distinguish from other large structures of dust and gas that make up the Galaxy known as the “Galactic Cirrus.” It’s like trying to see an individual cloud in an overcast sky. The Galactic Cirrus also outshines Hoinga in radio light, often used to search for SNRs, forcing Hoinga to hide in the background. Cross referencing with older radio sky surveys, the research team determined Hoinga had been observed before but was never identified as an SNR due to its comparatively faint glow in radio. Here eROSITA has an advantage as it sees X-rays. Hoinga shines brighter in X-ray light than the Galactic Cirrus allowing it to stand out from the Galaxy to be discovered.