PHYS 118 Intro Astronomy: The Milky Way II and Dark Matter

Flashcards covering key vocabulary and concepts from the lecture on the Milky Way and dark matter.

Sagittarius A*

The supermassive black hole at the center of the Milky Way, estimated to have a mass of 4.297 million solar masses.

Event Horizon Telescope

A collaboration of telescopes that captured the first image of a black hole, specifically Sagittarius A*.

Dark Matter

A form of matter that does not emit or reflect light and is inferred from gravitational effects, making up 90% of the total mass of galaxies.

Galaxy Rotation Curves

Graphs that plot the orbital speeds of stars against their distance from the galactic center, showing unexpected constant velocity behavior.

MACHOs

Massive Compact Halo Objects, a proposed form of dark matter that consists of ordinary matter but is difficult to detect.

WIMPs

Weakly Interacting Massive Particles, hypothesized particles that make up dark matter and interact via the weak nuclear force.

Gravitational interactions

The method by which astronomers currently detect dark matter, as it does not interact with light.

Constant Orbital Speeds

Observations showing that stars farther from the galactic center maintain similar speeds, contrary to expectations based on visible mass.

Primordial black holes

Hypothetical black holes formed soon after the Big Bang, which could be candidates for dark matter.

Fundamental Forces

The four forces that govern interactions in the universe: gravity, electromagnetism, the weak nuclear force, and the strong nuclear force.