Astronomers Capture First Image Of Elusive Dark Matter
Even as the existence of dark matter has come under debate, Canadian scientists have claimed they have been able to develop a composite image of dark matter for the first time.
Dark matter is mysterious energy that occupies 25 percent of the universe and more than 80 percent of galaxies. It neither absorbs nor reflects light. Being invisible, dark matter cannot be seen through traditional means except inferring the presence from gravity.
Connected Galaxies And Web Of Dark matter
Researchers from the University of Waterloo deserve credit for the proclaimed ability in having traced out the existence of dark matter using weak gravitational lensing technique.
The captured image curiously shows the face of a ghost-like object.
Weak gravitational lensing is a phenomenon that causes bending of light by the presence of massive structures in the galaxy.
"For decades, researchers have been predicting the existence of dark matter filaments between galaxies that act like a web-like superstructure connecting galaxies together," said Mike Hudson, a professor of astronomy at the University of Waterloo.
The study by Hudson and co-author Seth Epps of the Waterloo University has been published in Monthly Notices of the Royal Astronomical Society.
What Does The Composite Image Imply?
Using the Canada-France-Hawaii Telescope, the researchers detected dark matter from weak gravitational lensing that changes a galaxy's shape by 1 percent. They understood that bending of light can happen even from the gravity of smaller cosmic objects like dark matter.
The team created a composite image or map from galaxy pairs numbering more than 23,000 located at 4.5 billion light-years away. The image showed up a bridge-like structure connecting galaxies. It established dark matter's extensive interaction with galaxies.
Hudson called the successful mapping as a convenient step in convincing that dark matter is really there. So far, despite the theoretical concept, dark matter has eluded quantitative evidence.
Studies have already suggested dark matter exercises maximum stability between systems that are less than 40 million light years apart.
"By using this technique, we're not only able to see that these dark matter filaments in the universe exist, we're able to see the extent to which these filaments connect galaxies together," said Epps.
The concept of dark matter came to the fore in the 1930s when astronomers argued that galaxies cannot have the necessary gravity to maintain their structures merely with visible matter like stars, planets, and dust. They argued there is more that binds galaxies preventing them from breaking apart.
Axions As Constituents Of Dark Matter
The new study also corroborates the long-held theory of a cosmic scaffolding supporting stars and galaxies.
Some studies also mention a particle called the axion as the constituent of dark matter. It was first mooted in 1977 as new additions to the Standard Model in particle physics.
If axions are what make up dark matter, they may be detectable through gravitational waves because axions, when accelerated by black holes, would give off gravitational waves just like electromagnetic waves coming out of electrons.