Apr 25, 2021 08:48 PM
(This post was last modified: Apr 25, 2021 09:44 PM by C C.)
What is a supermoon?
https://earthsky.org/astronomy-essential...-supermoon
EXCERPTS: . . . The hype aspect of supermoons probably stems from an erroneous impression people had when the word supermoon came into popular usage … maybe a few decades ago? Some people mistakenly believed a full supermoon would look much, much bigger to the eye. It doesn’t. Full supermoons don’t look bigger to the eye than ordinary full moons, although experienced observers say they can detect a difference.
But supermoons do look brighter than ordinary full moons! The angular diameter of a supermoon is about 7% greater than that of the average-size full moon and 14% greater than the angular diameter of a micro-moon (year’s farthest and smallest full moon). Yet, a supermoon exceeds the area (disk size) and brightness of an average-size full moon by some 15%, and the micro-moon by some 30%. For a visual reference, the size difference between a supermoon and micro-moon is proportionally similar to that of a U.S. quarter versus a U.S. nickel.
[...] What’s more, Earth’s oceans feel the extra pull of supermoons. All full moons (and new moons) combine with the sun to create larger-than-usual tides, called spring tides. But closer-than-average full moons (or closer-than-average new moons) – that is, supermoons – elevate the tides even more. These extra-high spring tides are wide-ranging. High tides climb up especially high, and, on the same day, low tides plunge especially low. Experts call these perigean spring tides, in honor of the moon’s nearness. If you live along an ocean coastline, watch for them! They typically follow the supermoon by a day or two... (MORE - details)
If these magnetic fields exist, it could settle a debate over the universe's expansion rate
https://academictimes.com/if-these-magne...sion-rate/
INTRO: Researchers have shown it's possible that some magnetic fields in the cosmos date back to the beginning of time, and if the prospect proves accurate, it could address a conundrum wreaking havoc among physicists.
In the long and heated debate about quantifying how fast the universe is expanding, so-called Hubble tension, scientists have taken varying mathematical approaches and scrutinized for errors, only to calculate different answers. But now, a paper published April 9 in Monthly Notices of the Royal Astronomical Society offers new data about the early universe's magnetic fields that might be the missing puzzle piece.
Study author Sergio Martin-Alvarez, a postdoctoral researcher at the University of Cambridge, uncovered that some strong magnetic fields could be the consequence of Big Bang-induced quantum fluctuations, making them primordial. The results were pulled from his team's comprehensive simulations of a galaxy much like the Milky Way.
"A collaborator and myself, we developed this idea that is like a code, that gives you a way to see how different species of magnetic fields evolve in simulations," Martin-Alvarez said. He added that the researchers wanted to "see if the magnetic field affects the galaxy by itself and survives the entire formation of the galaxy — just to check."
If a field were able to endure galaxy formation, it would mean the prospect of primordial magnetic fields can't be eliminated.
"That's the tip of the iceberg," Martin-Alvarez told The Academic Times. "Because we know very well that if a magnetic field becomes strong enough, we'll have to consider whether this entire Hubble tension business is just based on the fact that we don't understand the early universe enough."
According to Scientific American, the persistent dilemma was discussed in 2019 at a conference at the Kavli Institute for Theoretical Physics in Santa Barbara, California, during which David Gross, a particle physicist and the institute's former director, remarked, "Do we have a 'tension,' or do we have a 'problem'?" He later clarified, "We wouldn't call it a tension or a problem, but rather a crisis."
Terminology aside, disagreement over the Hubble constant is raging... (MORE - details)
https://earthsky.org/astronomy-essential...-supermoon
EXCERPTS: . . . The hype aspect of supermoons probably stems from an erroneous impression people had when the word supermoon came into popular usage … maybe a few decades ago? Some people mistakenly believed a full supermoon would look much, much bigger to the eye. It doesn’t. Full supermoons don’t look bigger to the eye than ordinary full moons, although experienced observers say they can detect a difference.
But supermoons do look brighter than ordinary full moons! The angular diameter of a supermoon is about 7% greater than that of the average-size full moon and 14% greater than the angular diameter of a micro-moon (year’s farthest and smallest full moon). Yet, a supermoon exceeds the area (disk size) and brightness of an average-size full moon by some 15%, and the micro-moon by some 30%. For a visual reference, the size difference between a supermoon and micro-moon is proportionally similar to that of a U.S. quarter versus a U.S. nickel.
[...] What’s more, Earth’s oceans feel the extra pull of supermoons. All full moons (and new moons) combine with the sun to create larger-than-usual tides, called spring tides. But closer-than-average full moons (or closer-than-average new moons) – that is, supermoons – elevate the tides even more. These extra-high spring tides are wide-ranging. High tides climb up especially high, and, on the same day, low tides plunge especially low. Experts call these perigean spring tides, in honor of the moon’s nearness. If you live along an ocean coastline, watch for them! They typically follow the supermoon by a day or two... (MORE - details)
If these magnetic fields exist, it could settle a debate over the universe's expansion rate
https://academictimes.com/if-these-magne...sion-rate/
INTRO: Researchers have shown it's possible that some magnetic fields in the cosmos date back to the beginning of time, and if the prospect proves accurate, it could address a conundrum wreaking havoc among physicists.
In the long and heated debate about quantifying how fast the universe is expanding, so-called Hubble tension, scientists have taken varying mathematical approaches and scrutinized for errors, only to calculate different answers. But now, a paper published April 9 in Monthly Notices of the Royal Astronomical Society offers new data about the early universe's magnetic fields that might be the missing puzzle piece.
Study author Sergio Martin-Alvarez, a postdoctoral researcher at the University of Cambridge, uncovered that some strong magnetic fields could be the consequence of Big Bang-induced quantum fluctuations, making them primordial. The results were pulled from his team's comprehensive simulations of a galaxy much like the Milky Way.
"A collaborator and myself, we developed this idea that is like a code, that gives you a way to see how different species of magnetic fields evolve in simulations," Martin-Alvarez said. He added that the researchers wanted to "see if the magnetic field affects the galaxy by itself and survives the entire formation of the galaxy — just to check."
If a field were able to endure galaxy formation, it would mean the prospect of primordial magnetic fields can't be eliminated.
"That's the tip of the iceberg," Martin-Alvarez told The Academic Times. "Because we know very well that if a magnetic field becomes strong enough, we'll have to consider whether this entire Hubble tension business is just based on the fact that we don't understand the early universe enough."
According to Scientific American, the persistent dilemma was discussed in 2019 at a conference at the Kavli Institute for Theoretical Physics in Santa Barbara, California, during which David Gross, a particle physicist and the institute's former director, remarked, "Do we have a 'tension,' or do we have a 'problem'?" He later clarified, "We wouldn't call it a tension or a problem, but rather a crisis."
Terminology aside, disagreement over the Hubble constant is raging... (MORE - details)