Browse Reference Articles
31 to 40 of 193 articles
-
Hubble Deep Field
The Hubble Deep Field (HDF) is an image of a small region of the sky, based on the results of a series of observations by the Hubble Space Telescope. The field is so small that only a few foreground ... > more -
Dark matter
In astrophysics and cosmology, dark matter is hypothetical matter of unknown composition that does not emit or reflect enough electromagnetic radiation to be observed directly, but whose presence can ... > more -
Cosmic microwave background radiation
In cosmology, the cosmic microwave background radiation is a form of electromagnetic radiation discovered in 1965 that fills the entire universe. It has a thermal 2.725 kelvin black body spectrum ... > more -
Electromagnetic spectrum
The electromagnetic spectrum is the range of all possible electromagnetic radiation. Above infrared in frequency comes visible light. This is the range in which the sun and stars similar to it emit ... > more -
Solar wind
A solar wind is a stream of charged particles (i.e., a plasma) which are ejected from the upper atmosphere of a star. When originating from stars other than the Earth's Sun, it is sometimes called a ... > more -
Gamma ray burst
Gamma-ray bursts are the most luminous physical phenomena in the universe known to the field of astronomy. They consist of flashes of gamma rays that last from seconds to hours, the longer ones being ... > more -
Spectroscopy
Spectroscopy is the study of spectra, that is, the dependence of physical quantities on frequency. Spectroscopy is often used in physical and analytical chemistry for the identification of ... > more -
Open cluster
An open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud, and are still loosely gravitationally bound to each other. In contrast, globular ... > more
Search ScienceDaily
Number of stories in archives: 140,690

