The hard X-ray background comes into view
The CXB covers a range of photon energies, with a peak around 40 kiloelectron volts (keV). The soft X-ray part of the background – photon energies between about 0.5 and 2 keV – was extensi...
Astronomy and physics dominate Science top ten
Confirmation that the universe is flat – expanding at just the right rate not to collapse – came from measurements of ripples in the cosmic background radiation left over from the big bang...
Read article: Astrophysics and cosmology: the golden age
Astrophysics and cosmology: the golden age
Our understanding of the universe has advanced immeasurably in the last century, and there seems no end to the wealth of new discoveries as we approach the next millennium
Clouds puzzles astronomers
Astronomers have argued about high-velocity clouds for over thirty-five years. Wakker and colleagues detected ionized sulphur in one such cloud using the Hubble Space Telescope. According to their cal...
More evidence for the accelerating universe
The first evidence for the accelerating universe came from observations of distant supernovae. However, the data were also consistent with an open universe – a universe that would expand forever...
Gas cloud defines extragalactic distance
The team were able to measure the distance because NGC4258 is one of 22 nearby galaxies that have active nuclei consisting of a supermassive black hole (over 100 million solar masses) surrounded by a ...
Read article: String theory: simple yet elegant
String theory: simple yet elegant
String theory dates back some 30 years, but it was the “first string revolution” of 1984 that intensified interest in this, the most promising candidate for a “theory of everything&#...
Read article: New age of precision cosmology
New age of precision cosmology
An eight-year effort to measure the Hubble constant has yielded a result
Cosmology bestsellers
1. The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory by Brian Greene A fascinating and thought-provoking journey through the mysteries of space, time, and ma...
Read article: Hubble finds planetary transition point
Hubble finds planetary transition point
The results help to confirm the view that other planetary systems form in ways similar to our solar system. The Kuiper belt is a disk of dust, gas and icy comets stretching from 40 to 10000 times the ...
