Arecibo Begins Search for Dark Galaxies

Feb 08, 2005
Arecibo  radio telescope

Fitted with a new compound eye, the Arecibo radio telescope in Puerto Rico last week began a multiyear effort to survey all the galaxies in a large swath of sky out to a distance of 800 million light years—a survey that may well uncover the often-theorized, but never-seen, "dark galaxies."

If they do exist, dark galaxies, would be vast clumps of primordial hydrogen and helium gas that have drifted through the universe for 10 billion years or more, but for some reason have never been able to turn that gas into stars. As such, they would account for at least some of the mysterious cosmic "dark matter," which makes itself known only by its gravitational effects on the ordinary, star-rich galaxies. Certainly the dark galaxies would have been missed by previous astronomical surveys, most of which were restricted to optical and infrared light; the cold hydrogen and helium of a dark galaxy would shine only at radio wavelengths—Arecibo's specialty.

Funded by the National Science Foundation and operated by the the National Astronomy and Ionosphere Center at Cornell University, the 305-meter-wide Arecibo Observatory telescope is the world's largest and most-sensitive single-dish radio telescope. Last year, its sensitivity was further boosted by the Arecibo L-Band Feed Array (ALFA): essentially a seven-pixel camera that will allow astronomers to collect data about seven times faster than before. The the survey project starting today has thus been dubbed ALFALFA, for Arecibo Legacy Fast Alfa Survey.

Explore further: N. America treated to partial solar eclipse Thurs.

add to favorites email to friend print save as pdf

Related Stories

What goes up must come down

40 minutes ago

Found in warm regions of the world, geckos are extremely capable of climbing up steep, smooth surfaces. To do so, they employ an adhesive system – a key evolutionary innovation that facilitates climbing ...

Hydraulic fracturing linked to earthquakes in Ohio

2 hours ago

Hydraulic fracturing triggered a series of small earthquakes in 2013 on a previously unmapped fault in Harrison County, Ohio, according to a study published in the journal Seismological Research Letters.

Perfect torque distribution for safe driving

3 hours ago

A limiting factor for the driving range of electric vehicles is the amount of energy supplied by the batteries. To recoup as much braking energy as possible, engineers at the Gear Research Centre (FZG) at ...

Recommended for you

Big black holes can block new stars

4 hours ago

Massive black holes spewing out radio-frequency-emitting particles at near-light speed can block formation of new stars in aging galaxies, a study has found.

MAVEN studies passing comet and its effects

4 hours ago

NASA's newest orbiter at Mars, MAVEN, took precautions to avoid harm from a dust-spewing comet that flew near Mars today and is studying the flyby's effects on the Red Planet's atmosphere.

POLARBEAR seeks cosmic answers in microwave polarization

4 hours ago

An international team of physicists has measured a subtle characteristic in the polarization of the cosmic microwave background radiation that will allow them to map the large-scale structure of the universe, ...

User comments : 0