Hours of research by our editors, distilled into minutes of clarity.
Hydrogen, present since the early universe, serves as fuel for the proton-proton chain, producing helium, which is then incorporated into the CNO cycle to produce carbon, nitrogen, and oxygen. Additional fusions of helium with these elements and subsequent decays via the alpha ladder produce elements up to iron and bismuth.
More massive stars burn through their fuel at ever-increasing rates, causing them to have shorter lifetimes than less massive stars, despite starting with more hydrogen to fuse. In clusters of stars that likely formed together, observing what mass stars are no longer fusing hydrogen estimates the age of the cluster.
Neutron stars are born in supernova explosions. They are stars with a couple of times our sun’s mass, squeezed into a sphere the size of an earthly city.
At 25, her doctoral thesis challenged the then-common belief that stars were composed similarly to Earth. Several years later, Henry Norris Russell, who had initially dismissed her findings, independently made the same discovery and received credit for it.
Decades in the making, JWST is designed to study the universe in infrared light, allowing it to see through cosmic dust and observe ancient galaxies, star formation, and potentially life-supporting exoplanets. The Webb will orbit the sun at a stable point 1.5 million kilometers from Earth.
Olbers' paradox asks why the sky would ever appear dark if the universe is full of stars in all directions emitting light everywhere. Light from the farthest stars requires more time to reach our skies than the universe's age.
The first stars only burned for millions of years, providing the universe's first heavy elements. Some in the current population will burn for trillions of years, delaying the appearance of black dwarfs and other exotic cold stars.
According to the Doppler Effect, light from objects moving away from Earth shifts toward the red end of the electromagnetic spectrum, with the severity of the shift correlating to recession speed. Due to the universe's expansion, light from the most distant galaxies can be moved from ultraviolet to infrared.
While the James Webb telescope collects an astounding amount of scientific data, a major part of its allure is its ability to return stunning, high-resolution images. These images include nearby stars, distant galaxies, and some of the oldest structures in the universe.
These explosions are all caused by exploding white dwarfs—remnants of dead, low-mass stars—and have the same peak brightness. By comparing them, astronomers have mapped the locations of galaxies alongside redshift data to determine the universe's expansion rate across time.
From roughly 60 miles above the Earth's surface to farther than light has traveled during the entire age of the universe, space has captured human imagination for millennia. Explore the final frontier with the best resources curated from across the internet.