Think about background radiation and most people immediately think of the cosmic background radiation and stories of pigeon excrement during its discovery. That’s for another day though. Turns out that the universe has several background radiations, such as infrared and even gravitational wave backgrounds. NASA’s New Horizons is far enough out of the Solar System now that it’s in the perfect place to measure the cosmic optical background (COB). Most of this light comes from the stars in galaxies, but astronomers have always wondered if there are other sources of light filling our night sky. New Horizons has an answer. No!
Continue reading “New Horizons Measures the Background Light of the Universe”Galaxies Filled With Old Stars Seen Shortly After the Big Bang
How can young galaxies in the early Universe have ancient stars? That’s the question a team of astronomers set out to answer using JWST as a probe. They first spotted the massive objects in 2022 and are still working to explain what these things are.
Continue reading “Galaxies Filled With Old Stars Seen Shortly After the Big Bang”Webb Sees Globular Clusters Forming in the Early Universe
Picture the Universe’s ancient beginnings. In the vast darkness, light was emitted from a particular galaxy only 460 million years after the Big Bang. On the way, the light was shifted into the infrared and magnified by a massive gravitational lens before finally reaching the James Webb Space Telescope.
The galaxy is called the Cosmic Gems arc, and it held some surprises for astronomers.
Continue reading “Webb Sees Globular Clusters Forming in the Early Universe”Baby Stars are Swarming Around the Galactic Center
The vicinity of Sagittarius A* (Sgr A*), the supermassive black hole at the Milky Way’s center, is hyperactive. Stars, gas, and dust zip around the black hole’s gravitational well at thousands of kilometers per hour. Previously, astronomers thought that only mature stars had been pulled into such rapid orbits. However, a new paper from the University of Cologne and elsewhere in Europe found that some relatively young stars are making the rounds rather than older ones, which raises some questions about the models predicting how stars form in these hyperactive regions.
Continue reading “Baby Stars are Swarming Around the Galactic Center”Rotation Curves of Galaxies Stay Flat Indefinitely
In his classic book On the Structure of Scientific Revolutions, the philosopher Thomas Kuhn posited that, for a new scientific framework to take root, there has to be evidence that doesn’t sit well within the existing framework. For over a century now, Einstein’s theory of relativity and gravity has been the existing framework. However, cracks are starting to show, and a new paper from researchers at Case Western Reserve University added another one recently when they failed to find decreasing rotational energy in galaxies even millions of light years away from the galaxy’s center.
Continue reading “Rotation Curves of Galaxies Stay Flat Indefinitely”New Simulation Explains how Supermassive Black Holes Grew so Quickly
One of the main scientific objectives of next-generation observatories (like the James Webb Space Telescope) has been to observe the first galaxies in the Universe – those that existed at Cosmic Dawn. This period is when the first stars, galaxies, and black holes in our Universe formed, roughly 50 million to 1 billion years after the Big Bang. By examining how these galaxies formed and evolved during the earliest cosmological periods, astronomers will have a complete picture of how the Universe has changed with time.
As addressed in previous articles, the results of Webb‘s most distant observations have turned up a few surprises. In addition to revealing that galaxies formed rapidly in the early Universe, astronomers also noticed these galaxies had particularly massive supermassive black holes (SMBH) at their centers. This was particularly confounding since, according to conventional models, these galaxies and black holes didn’t have enough time to form. In a recent study, a team led by Penn State astronomers has developed a model that could explain how SMBHs grew so quickly in the early Universe.
Continue reading “New Simulation Explains how Supermassive Black Holes Grew so Quickly”If Gravity Can Exist Without Mass, That Could Explain Dark Matter
Dark Matter is Nature’s poltergeist. We can see its effects, but we can’t see it, and we don’t know what it is. It’s as if Nature is playing tricks on us, hiding most of its mass and confounding our efforts to determine what it is.
Continue reading “If Gravity Can Exist Without Mass, That Could Explain Dark Matter”Primordial Black Holes Can Only Explain a Fraction of Dark Matter
What is Dark Matter? That question is prominent in discussions about the nature of the Universe. There are many proposed explanations for dark matter, both within the Standard Model and outside of it.
One proposed component of dark matter is primordial black holes, created in the early Universe without a collapsing star as a progenitor.
Continue reading “Primordial Black Holes Can Only Explain a Fraction of Dark Matter”The JWST is Re-Writing Astronomy Textbooks
When the James Webb Space Telescope was launched at the end of 2021, we expected stunning images and illuminating scientific results. So far, the powerful space telescope has lived up to our expectations. The JWST has shown us things about the early Universe we never anticipated.
Some of those results are forcing a rewrite of astronomy textbooks.
Continue reading “The JWST is Re-Writing Astronomy Textbooks”Some Clever Ways to Search for Primordial Black Holes
Primordial Black Holes (PBHs) have recently received much attention in the physics community. One of the primary reasons is the potential link to dark matter. In effect, if PBHs can be proven to exist, there’s a very good chance that they are what dark matter, the invisible thing that makes up 85% of the universe’s mass, is made of. If proven, that would surely be a Nobel-level discovery in astrophysics.
Continue reading “Some Clever Ways to Search for Primordial Black Holes”