- Astronomers have mapped about a million previously undiscovered galaxies beyond the Milky Way.
- To make the map, referred to as “the Google Map of the Universe,” the team used radio telescopes to scour the night sky.
- The team surveyed 83% of the sky in just 10 days.
- You can take a tour of the 3-D map below.
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Astronomers have mapped about a million previously undiscovered galaxies beyond the Milky Way, in the most detailed survey of the southern sky ever carried out using radio waves.
The Rapid ASKAP Continuum Survey (or RACS) has placed the CSIRO’s Australian SKA Pathfinder radio telescope (ASKAP) firmly on the international astronomy map.
While past surveys have taken years to complete, ASKAP’s RACS survey was conducted in less than two weeks — smashing previous records for speed. Data gathered have produced images five times more sensitive and twice as detailed as previous ones.
What is radio astronomy?
Modern astronomy is a multi-wavelength enterprise. What do we mean by this?
Well, most objects in the universe (including humans) emit radiation over a broad spectrum, called the electromagnetic spectrum. This includes both visible and invisible light such as X-rays, ultraviolet light, infrared light and radio waves.
To understand the universe, we need to observe the entire electromagnetic spectrum as each wavelength carries different information.
Radio waves have the longest wavelength of all forms of light. They allow us to study some of the most extreme environments in the universe, from cold clouds of gas to supermassive black holes.
Long wavelengths pass through clouds, dust and the atmosphere with ease, but need to be received with large antennas. Australia’s wide open (but relatively low-altitude) spaces are the perfect place to build large radio telescopes.
We have some of the most spectacular views of the centre of the Milky Way from our position in the Southern Hemisphere. Indigenous astronomers have appreciated this benefit for millennia.
A stellar breakthrough
Radio astronomy is a relatively new field of research, dating back to the 1930s.
The first detailed 30cm radio map of the southern sky — which includes everything a telescope can see from its location in the Southern Hemisphere — was Sydney University’s Molonglo Sky Survey. Completed in 2006, this survey took almost a decade to observe 25% of the entire sky and produce final data products.
Our team at CSIRO’s Astronomy and Space Science division has smashed this record by surveying 83% of the sky in just ten days.
With the RACS survey we produced 903 images, each requiring 15 minutes of exposure time. We then combined these into one map covering the entire area.
The resulting panorama of the radio sky will look surprisingly familiar to anyone who has looked up at the night sky themselves. In our photos, however, nearly all the bright points are entire galaxies, rather than individual stars.
Take our virtual tour below.
Astronomers working on the catalogue have identified about three million galaxies — considerably more than