Naturvitenskap er spennende. Ikke minst i disse tider hvor man innen fysikk gjør stadig nye oppdagelser innen kvantemekanikk, kosmologi og ikke minst forsøk på å bekrefte Einsteins betraktninger. Ofte leser jeg et fysikk kapittel eller hører en podcast om fysikk. Informasjon jeg synes er interessant vil jeg samle i denne posten.
Some of the first inklings astronomers had that there might be more mass in the universe than just the stuff we can see came in the 1960s and 1970s. Vera Rubin, a young astronomer at the Department of Terrestrial Magnetism at the Carnegie Institution of Washington, observed the speeds of stars at various locations in galaxies. Simple Newtonian physics predicted that stars on the outskirts of a galaxy would orbit more slowly than stars at the center. Yet Rubin’s observations found no drop-off at all in the stars’ velocities further out in a galaxy. Instead, she found that all stars in a galaxy seem to circle the center at roughly the same speed. But research by other astronomers confirmed the odd finding. Ultimately, based on observations and computer models, scientists concluded that there must be much more matter in galaxies than what’s obvious to us. If the stars and gas that we can see inside galaxies are only a small portion of their total mass, then the velocities make sense.
It all started in the mid-1990s, when two teams of researchers were trying to figure out how fast the universe was expanding, in order to predict whether it would keep spreading out forever, or if it would eventually crumple back in on itself in a “Big Crunch.” To do this, scientists used special tricks to determine the distances of many exploded stars, called supernovas, throughout the universe. They then measured their velocities to determine how fast they were moving away from us. When we view very distant stars, we are viewing an earlier time in the history of the universe, because those stars’ light has taken millions and billions of light-years to travel to us. Thus, looking at the speeds of stars at various distances tells us how fast the universe was expanding at various points in its lifetime. Astronomers predicted two possibilities: either the universe has been expanding at roughly the same rate throughout time, or that the universe has been slowing in its expansion as it gets older. Shockingly, the researchers observed neither possibility. Instead, the universe appeared to be accelerating in its expansion. That fact could not be explained based on what we knew of the universe at that time. All the gravity of all the mass in the cosmos should have been pulling the universe back inward, just as gravity pulls a ball back down to Earth after it’s been thrown into the air. “There’s some other force out there or something on a cosmic scale that is counteracting the force of gravity,” writer Richard Panek explained. “People didn’t believe this at first because it’s such a weird result.”
Elektronkonfigurasjon fysikk møter kjemi
In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals. For example, the electron configuration of the neon atom is 1s2 2s2 2p6, meaning that the 1s, 2s and 2p subshells are occupied by 2, 2 and 6 electrons respectively. pi bond.