Hot gas has been detected in cosmic filaments
Cosmic filaments are superstructures of matter… Close your eyes to imagine their size: Imagine our solar system, step back and zoom out a little, now you see our galaxy, the Milky Way, zoom out again, you see clusters of galaxies… zoom in again, these cluster nodes represents and now you see the long filaments connecting them… you are there. This is called a space network. That is, the baryonic matter we see is not evenly distributed in the universe… forming a giant spider’s web. At the intersection of these filaments are clusters of galaxies. And between these filaments there are gaps.
If we only observe galaxies fairly easily, because they emit a lot of light… The gas that we assume exists between these groups of galaxies, and therefore forms the filaments, is very difficult to observe.
So the researchers focused on any part of the sky. From a galaxy survey called the SDSS, they quickly connected the dots between different galaxies. In total, they identified 460 filaments. And then, this time using data from the eRosita satellite, they looked at X-rays.
And eventually they were able to determine the presence of hot gas between the galaxies…thus confirming the presence of matter in these cosmic filaments. This is one of the few direct observations of these filaments to date. And with more information, it will allow us to better understand the formation of the cosmic web.
Interview with Marian Douspis Astronomer at the Space Astrophysics Institute of the Space Sciences Observatory of the University of Paris Saclay and co-author of the study
Environmental DNA reveals 2-million-year-old ecosystem
Environmental DNA is DNA taken from environmental samples, water, soil, or sediment, not from an organism. The idea is not to identify the presence of a single species in particular, but to identify as many as possible, fauna and flora, by the DNA traces they leave in the environment… and thus recreate the entire ecosystem. We quickly realize that this performance is based on the sensitivity of the sequence….
A sensitivity that these researchers didn’t have in 2006… When they got the first sediment samples from Greenland… It took the last couple of years to get them to talk… And as a result, a river flowed north of Greenland… a forest, poplars, tussocks that worked. … and the presence of algae reveals that the climate was much warmer 2 million years ago than it is today… On the faunal side, rabbits, mastodons, extinct species, a kind of mix between an elephant and a mammoth … also reindeer, rodents, geese, bugs…
That’s a feat… because the oldest DNA ever sequenced was a mammoth fossil that’s about a million years old… while these are DNA traces from many plants and animals twice as old. The lead author has already started the same type of research around the world….and since our ability to extract DNA can still improve, he hopes to go even further back in time.
A volcanic eruption was detected on the comet
It is a cryo-volcanic comet… the most active in our solar system. It is named 29P/Schwassmann-Wachman in honor of the two German astronomers who discovered it in 1927…
On November 22nd, amateur astronomers from the British Astronomical Association detected a strong glow from a comet… a sign of an eruption. But unlike what happens on Earth, this comet spits out cold gases and ice, hence the name cryovolcanism or cold volcanism. Now it remains to study their images to better understand what causes these eruptions.
Traffic noise makes country robins more aggressive
These birds are territorial by nature. When an opponent approaches, it is greeted with screams … and certain defensive behaviors, such as the robin’s tendency to show its red feathers and swing sideways before attacking.
Researchers from Great Britain and Turkey have devised a trick to study the effects of urban noise on the behavior of these birds: a 3D-printed robin on a lawn. And an additional element, the attraction is equipped with speakers and can broadcast songs or traffic sounds. As a result, birds exposed to noise in a quiet environment at first become more aggressive, approach the opponent closer and for a longer time. This poses a threat to the survival of these birds… because by spending more time fighting off rivals and increasing the number of territorial battles, robins pay less attention to other predators in their environment and may not escape quickly enough.
