
One Universe at a Time
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The goal of One Universe at a Time is to convey an understanding of our Universe in a way that is honest and free of hype. Modern astrophysics is complex, and the conclusions we can draw from our findings is often subtle. One Universe at a Time focuses on peer-reviewed evidence to present our best current knowledge. When there is scientific controversy, various views will be discussed.
One Universe at a Time
2d ago
Science Communication Lab for MPIK/H.E.S.S. Artist’s impression of a microquasar system.
The Earth is bathed in high-energy particles. Known as cosmic rays, most of them are protons striking us at nearly the speed of light. Fortunately, the atmosphere protects us from any significant harm, though the particles can strike with so much energy that they create a shower of lower energy particles that do reach Earth’s surface. That’s actually how we can detect most cosmic rays.
We aren’t entirely sure what accelerates these particles so tremendously. There are phenomena that can do it. Nearby super ..read more
One Universe at a Time
3d ago
Mark A. Garlick A Ceres-like planet orbits a white dwarf star.
When we first began searching for planets around other stars, one of the surprising discoveries was that there are planets orbiting white dwarfs. The first exoplanets we ever discovered were white dwarf planets. Of course, these planets were barren and stripped of any atmosphere, so we had to look at main sequence stars to find potentially habitable worlds. Or so we thought.
As we discovered more white dwarf planets, it became clear that some of them might retain atmospheres and water. Perhaps they were an outer planet with a thick ..read more
One Universe at a Time
6d ago
ESA Artist’s impression of asteroid 2024 YR4.
The odds of a sizable asteroid striking Earth are small, but they’re never zero. Large asteroids have struck Earth in the past, causing regional devastation. A really large asteroid strike likely contributed to the extinction of the dinosaurs. So we shouldn’t be too surprised that astronomers have discovered an asteroid with a better than 1% chance of striking our world. Those odds are large enough we should keep an eye on them, but not large enough that we should start packing bags and fleeing to the hills.
The rock, named 2024 YR4, is somewhere b ..read more
One Universe at a Time
1w ago
Instituto Galego de Física de Altas Enerxías (IGFAE) Illustration of a black hole recoil and its mirror symmetrical recoil.
The structure of the cosmos is rooted in symmetry. As first demonstrated by Emmy Noether in 1918, for every physical law of conservation in the Universe, there is a corresponding physical symmetry. For example, all other things being equal, a baseball hit by a bat today will behave exactly the same as it did yesterday. This symmetry of time means that energy is conserved. Empty space is the same everywhere and in all directions. This symmetry of space means that there is ..read more
One Universe at a Time
1w ago
OPENVERSE/Einstein Probe Science Center Einstein Probe detects ancient X-ray burst (artist impression).
The Einstein Probe was launched in January 2024 to look at X-ray transients, among other things. Its power comes from its Wide-field X-ray Telescope (WXT), which can capture 3600 square degrees of the sky in a single go. That’s an area 18,000 times the apparent area of the Moon. That is a huge patch of astronomical sky, so it’s not surprising that just two months later the probe saw a 17-minute burst of soft X-rays. Given the name EP240315a, it is an example of a fast X-ray transient (FXRT ..read more
One Universe at a Time
1w ago
CHIME, Andre Renard, Dunlap Institute for Astronomy & Astrophysics, University of Toronto Astronomers first detected the new FRB, dubbed FRB 20240209A, in February 2024 with the Canadian Hydrogen Intensity Mapping Experiment (CHIME).
Fast radio bursts (FRBs) are intense flashes of radio light that last for only a fraction of a second. They are likely caused by the intense magnetic fields of a magnetar, which is a highly magnetic neutron star. Beyond that, FRBs remain a bit of a mystery. We know that most of them originate from outside our galaxy, though the few that have occurred within ou ..read more
One Universe at a Time
2w ago
ESO/L. Calçada Artist’s visualisation of WASP-127b shows supersonic jet winds that move around the planet’s equator.
The exoplanet WASP-127b is an unusual world. It is about 30% larger than Jupiter but has just a fifth of Jupiter’s mass. It is an example of a super-puff planet because of its extremely low density. These puffy worlds are so unusual that we don’t know if they would resemble the gas giants of our solar system, or something more exotic, such as a large super-Earth. But a recent study of WASP-127b shows that super-puff worlds can have tremendous winds.1
The team used the CRyogenic ..read more
One Universe at a Time
3w ago
ESO/M. Kornmesser This artist’s impression shows CR7 a very distant galaxy discovered using ESO’s Very Large Telescope.
Water is the essence of life. Every living thing on Earth contains water within it. The Earth is rich with life because it is rich with water. This fundamental connection between water and life is partly due to water’s extraordinary properties, but part of it is due to the fact that water is one of the most abundant molecules in the Universe. Made from one part oxygen and two parts hydrogen, its structure is simple and strong. The hydrogen comes from the primordial fire of th ..read more
One Universe at a Time
3w ago
EHT Collaboration Image of the supermassive black hole Sag A* seen in polarized light.
There is a gravitational monster at the heart of our galaxy. Known as Sagittarius A*, it is a supermassive black hole with a mass of more than four million Suns. Long-term observations of the stars closely orbiting Sag A* place it at about 4.3 solar masses, give or take 100,000 or so. Observations of light near its horizon by the Event Horizon Telescope pin the mass down to 4.297 solar masses, give or take about 10,000. Those results are astoundingly precise given how difficult the mass is to measure, but su ..read more
One Universe at a Time
1M ago
IAU CPS/NOIRLab/SKAO How constellation satellites can create light pollution for radio telescopes.
When was the last time you looked up into the night sky and saw the Milky Way? If you happen to live in one of the truly remote areas of the world, your answer might be “last night.” If you live in one of the generally “rural” areas of your country, you might remember how you used to see the Milky Way regularly, but the rise of LEDs, particularly the blue/white ones, has gradually erased the Milky Way from your nights. For the large majority of humans on our small world, the answer is “never.”
Li ..read more