astronomy

From Super Interessante, Jan. 31, 2021: A team of researchers from Fermilab and the National Observatory in Brazil used the light of solitary stars to calculate the mass of some of the largest structures in the cosmos — galaxy clusters. In addition to taking the most detailed measurement ever published of intracluster light, the team’s new method of measurement can help further investigate dark matter.

Five billion years ago what was to become the sun was a vast cloud of very thin gas, mostly hydrogen and helium from the Big Bang. There were also heavier elements like carbon, oxygen, iron, gold and all the others; they came from stars that collapsed and then exploded, flinging those atoms across space. That rarefied cloud was bigger than what became our solar system and was surrounded by a more perfect vacuum. Slowly it contracted under its own gravity.

From Forbes, Jan. 22, 2021: Fermilab scientist Don Lincoln describes recent findings of scientists studying an unexplained excess of hard X-rays emanating from neutron stars. The explanation for the excess could lie in a hypothesized dark matter candidate called the axion.

From Forbes, Dec. 27, 2020: Astronomers have long known that the matter that they’ve seen is less than half of the atomic matter that exists. Several hypotheses have been advanced as to where that matter could be found. Fermilab scientist Don Lincoln describes how a team of astronomers has combined a series of astronomical facilities, including the Dark Energy Camera, to look for a filament of gas connecting two galaxy clusters. They were able to image the largest and hottest filament recorded to date.

From CNN, Dec. 18, 2020: Fermilab scientist Don Lincoln summarizes the results of a group of researchers who, through simulation, reconstruct the family tree of the Milky Way, including the merging of the previously unknown dwarf galaxy Kraken.

For all antiquity nobody knew what stars were. When Copernicus realized that the sun, not Earth, is the center of the universe, the stars were placed on a far distant giant sphere. Some thought they might be holes through which shone the light of heaven. Copernicus, who was nineteen when Columbus first sailed across the Atlantic, started the Scientific Revolution, followed by Galileo and Newton, and the Age of Discovery began.

While we’ve known about neutron stars for the better part of a century, astrophysicists still aren’t entirely sure how large they are. That uncertainty is related to two other unanswered questions: What’s in the middle of neutron stars, and how massive can they grow? Astrophysicists are combining multiple methods to reveal the secrets of some of the weirdest objects in the universe.