1. Green stars.
- Author
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Murphy, Matthew, Klesman, Alison, and Impey, Chris
- Subjects
- *
STARS , *DARK energy , *BLACK holes , *STAR clusters , *GLOBULAR clusters , *SOLAR system - Abstract
This article from Astronomy magazine addresses several questions related to astronomy. The first question asks why there are no green stars. The answer explains that the color of stars is determined by their temperature, with hotter stars appearing blue and cooler stars appearing red. Green is a specific frequency that cannot dominate over other colors in the spectrum emitted by stars. The second question discusses how black holes end up in the center of galaxies. Stellar-mass black holes can be randomly kicked in any direction when they are created, so they don't necessarily end up in the center of a galaxy. Supermassive black holes, on the other hand, are different and are believed to form around the same time as galaxies. However, the gravitational interactions between supermassive black holes and their host galaxies are minor, and most stars in a galaxy orbit the center of mass of the galaxy rather than the black hole. The third question explores the percentages of dark matter and dark energy in the universe and whether they are stable or changing. Dark matter makes up most of the mass of galaxies and is not visible, while dark energy is causing the universe to expand at an accelerating rate. The amounts of dark matter and dark energy are believed to be the same in every direction and have remained relatively constant over cosmic time. The final question addresses how globular clusters remain intact for long periods of time without stars colliding. The answer explains that the angular momentum of the stars in a globular cluster keeps the cluster from collapsing, and the average distance between stars [Extracted from the article]
- Published
- 2024