Hertzsprung-Russell Diagram

In the previous post, we saw that intensity of radiation emitted by a star is proportional to its temperature to the fourth power. Let’s now use that to find a formula for a star’s luminosity. In order to calculate luminosity, we multiply intensity by the surface area of the object. Since, we assume that allContinue reading “Hertzsprung-Russell Diagram”

Blackbody Radiation

Blackbody radiation is a fascinating concept that shines some light (hehe) on quantum phenomena and stars. Planck’s research into the ultraviolet catastrophe at the beginning of the 20th century jumpstarted quantum physics. An ideal blackbody is an object that absorbs all radiation incident on it, and then emits 100% of it. This means that theContinue reading “Blackbody Radiation”

The Expansion of the Universe

Since the dawn of humanity, we have thought that the heavens are huge, but of constant size. We first knew that the stars move around, then that it is actually the Earth rotating on its axis. In the 18th century, the French astronomer Messier observed fuzzy objects that he didn’t know were galaxies. Only inContinue reading “The Expansion of the Universe”

The Formation of the Solar System

The solar system formed from a cloud of interstellar gas around 4.6 billion years ago. At some point, this cloud collapsed under gravity and the sun formed. The pressure in the center became so high that hydrogen atoms began fusing into helium, and the nuclear reactions that power stars begun. A solar nebula of gasContinue reading “The Formation of the Solar System”

Cosmic Microwave Background

Cosmic microwave background radiation (CMB) is the leftover radiation from the Big Bang and serves as a source of evidence for it actually happening. It is extremely cold at just 2.725 Kelvin, so emits blackbody wavelengths in the microwave part of the electromagnetic spectrum. It was discovered in 1964 by Arno Penzias and Robert Wilson,Continue reading “Cosmic Microwave Background”