To the extent that we can see them, galaxies in the very early universe should look relatively young and unformed. But galaxy ALESS 073.1 is a surprise to astronomers: it looks more mature than we’d have any reason to expect. Why? Source: https://earthsky.org/space/galaxy-looks-older-than-its-years-aless-073-1…
Tag: relativity
The First Black Hole Ever Discovered is More Massive Than We Thought
Neel V. Patel, writing at MIT Technology Review: Einstein first predicted the existence of black holes when he published his theory of general relativity in 1916, describing how gravity shapes the fabric of spacetime. But astronomers didn’t spot one until 1964, some 6,070 light-years away in the Cygnus constellation. Geiger counters launched into space detected cosmic x-rays coming from a region…
What is the Milky Way?
When someone says “Milky Way,” do you think of the starry pathway across our sky, or of the great pinwheel-shaped galaxy in space? Both are correct! Source: https://earthsky.org/astronomy-essentials/what-is-the-milky-way-galaxy…
AEgIS on track to test freefall of antimatter
It’s a fundamental law of physics that even the most ardent science-phobe can define: matter falls down under gravity. But what about antimatter, which has the same mass but opposite electrical charge and spin? According to Einstein’s general theory of relativity, gravity should treat matter and antimatter identically. Finding even the slightest difference in their free-fall rate would therefore lead to…
Extreme black holes have hair that can be combed
Black holes are considered amongst the most mysterious objects in the universe. Part of their intrigue arises from the fact that they are actually among the simplest solutions to Einstein’s field equations of general relativity. In fact, black holes can be fully characterized by only three physical quantities: their mass, spin and charge. Since they have no additional “hairy” attributes to…
Wormholes may be lurking in the universe—and new studies are proposing ways of finding them
Albert Einstein’s theory of general relativity profoundly changed our thinking about fundamental concepts in physics, such as space and time. But it also left us with some deep mysteries. One was black holes, which were only unequivocally detected over the past few years. Another was “wormholes”—bridges connecting different points in spacetime, in theory providing shortcuts for space travelers. Source: https://phys.org/news/2021-01-wormholes-lurking-universeand-ways.html…
The uncertainties in measuring cosmic expansion
Ninety years after Edwin Hubble discovered the systematic motions of galaxies and George Lemaitre explained them as cosmic expansion from a point using Einstein’s equations of relativity, observational cosmology today is facing a challenge. Values deduced from the two primary methodologies—the properties of galaxies and the cosmic microwave background radiation (CMBR)—disagree with each other at roughly the ten percent level, yet…
Happy birthday to Isaac Newton
Isaac Newton, born on January 4, 1643, discovered the laws of motion and other principles that laid the foundation of physics and astronomy. Source: https://earthsky.org/human-world/this-date-in-science-isaac-newtons-birthday…
Are Fragments of Energy the Fundamental Building Blocks of the Universe?
hcs_$reboot shares a remarkable new theory from Larry M. Silverberg, an aerospace engineering professor at North Carolina State University (with colleague Jeffrey Eischen). They’re proposing that matter is not made of particles (or even waves), as was long thought, but fragments of energy. [W]hile the theories and math of waves and particles allow scientists to make incredibly accurate predictions about the…
To Explain Away Dark Matter, Gravity Would Have To Be Really Weird
To discard the theory of dark matter, “you’ll need to replace it with something even more bizarre: a force of gravity that, at some distances, pulls massive objects together and, at other distances, pushes them apart.” That’s how Science magazine describes a new study, adding that “The analysis underscores how hard it is to explain away dark matter” — even though…