To the human eye, the Milky Way is a majestic, milky-white band dotted with billions of stars stretching across the night sky. But if we could see the Universe through the eyes of a radio telescope, we would discover that our galaxy is incomparably richer and more complex – a veritable cosmos of charged particles, hidden magnetic fields, and raging energy processes. Today, the scientific world is rejoicing after the first-ever full-color radio map of the Milky Way was unveiled, combining multiple observations into one stunning and informative dataset.
Unlike the optical signal, which is highly limiting and allows us to see only light, radio frequencies give us a full-blooded picture of galactic events. To turn these invisible frequencies into something understandable, scientists have applied ingenious coding:
Warm and bright colors (orange, red): These represent the lowest wavelengths, which indicate regions of supernova explosions and old, dying stars.
Cool colors (blue, violet): These reflect the high frequencies, which mark active regions of new star formation.
This colorful format is much more than aesthetics – it allows astronomers to instantly focus their attention on the most significant phenomena, revealing the location of cosmic dust, plasma and the echoes of stellar cataclysms.
The data behind this epic galactic portrait was collected thanks to the Murchison Widefield Array (MWA) radio telescope located in Australia. The facility, which resembles a giant network of 4,096 antennas, works tirelessly.
The survey combines data from two key stages: the initial observations from 2013–2015 (known as GLEAM) and the more recent, significantly improved data from 2018 (GLEAM-X), collected after the antenna array was renovated.
Combining these two arrays, however, has proven to be a titanic challenge. Conditions in the ionosphere have varied significantly over the years, making the data incompatible. It took millions of hours of supercomputer processing to synchronize and combine the two surveys! The effort has been crowned with success, however.
This combined survey covers an impressive 95% of the Milky Way visible from the Southern Hemisphere, operating in the 72–231 MHz range. To date, this is the most detailed and accurate color radio map of our galaxy.
If this map is impressive, then the future sounds downright science fiction. The next evolutionary leap in mapping will only come after the new SKA (Square Kilometre Array) radio telescope, which promises to be thousands of times more sensitive than the MWA, is put into operation. Until then, however, this map will remain a priceless treasure for astronomers studying the birth and death of stars in the Universe.