Astronomers have long suspected the existence of the invisible substance of dark matter as the source of additional gravity that holds together galaxy clusters. Otherwise, astronomers say, the clusters would fly apart if they relied only on the gravity from their visible stars. Although astronomers don't know what dark matter is made of, they hypothesize that it is a type of elementary particle that pervades the Universe.

Travellers have relied on accurate timekeeping for navigation since the development of the marine chronometer in the eighteenth century. Galileo, Europe’s twenty-first century navigation system, also relies on clocks – but they are millions of times more accurate than those earlier timepieces.

"HD 149026b is simply the most exotic, bizarre planet. It’s pretty small, really dense, and now we find that it’s extremely hot."

ESA’s X-ray observatory XMM-Newton has revealed a new class of exploding stars – where the X-ray emission ‘lives fast and dies young’.

The identification of this particular class of explosions gives astronomers a valuable new constraint to help them model and understand stellar explosions.XMM-Newton image of M 31. Credit: ESA

The brightest stellar explosion ever recorded may be a long-sought new type of supernova, according to observations by NASA's Chandra X-ray Observatory and ground-based optical telescopes.

Chefs have long used a simple trick to differentiate between a raw and hard-boiled egg. By spinning an egg and watching how it behaves when the spin is disrupted, it's easy to tell whether its interior is solid or liquid.

Applying a similar test to the planet Mercury, astronomers have found strong evidence that the planet closest to the sun has a fluid core. The research, led by Jean-Luc Margot, assistant professor of astronomy at Cornell, appears this week on the Web site of the journal Science.

COROT has provided its first image of a giant planet orbiting another star and the first bit of ‘seismic’ information on a far away, Sun-like star- with unexpected accuracy.

New observations by the NASA/ESA Hubble Space Telescope have overturned conventional ideas about the early life of some massive globular clusters, showing that they can go through several periods of intense stellar formation rather than the previously accepted single burst.

Want to know if the International Space Station is over you right now? You can view the location of ESA's Earth-orbiting spacecraft and other ESA-related missions in real-time via a new tracking site.Credits: ESA

Once the site loads, the tracker automatically starts displaying the location of the International Space station (ISS) and various observation missions.

Astronomers have discovered the most Earth-like planet outside our Solar System to date, an exoplanet with a radius only 50% larger than the Earth and capable of having liquid water. Using the ESO 3.6-m telescope, a team of Swiss, French and Portuguese scientists discovered a super-Earth about 5 times the mass of the Earth that orbits a red dwarf, already known to harbour a Neptune-mass planet.