Dark matter

Why in News?

• Researchers from S. National Science Foundation's (NSF) used the Atacama Cosmology Telescope to create this new map of the dark matter.
• The new image, made using 14 billion-year-old light from the turbulent aftermath of the Big Bang, shows the enormous matter tendrils that formed not long after the universe exploded into being.
• It turns out the shapes of these tendrils are remarkably similar to those predicted using Einstein's theory of general relativity.
• The new result contradicts previous dark matter maps that suggested the cosmic web is less clumpy than Einstein's theory predicted.

About Dark Matter:

• What is it? Dark matter is a hypothetical invisible mass thought to be responsible for adding gravity to galaxies and other bodies.
• How much is dark matter?
  • According to NASA, Dark matter seems to outweigh visible matter roughly six to one, making up about 27% of the universe.
  • Roughly 68% of the universe is dark energy. Dark matter makes up about 27%. The rest visible matter is 5% of the universe.
• Why called dark matter? It is called so because unlike normal matter (i.e. stars and galaxies), dark matter does not interact with the electromagnetic force.
• Detection: As it does not interact with the electromagnetic force, thus it does not absorb, reflect or emit light or electromagnetic radiation of any kind. And this makes it extremely hard to spot/detect. It can be detected only through its gravitational effects.
• Importance: Its gravitational force prevents stars in our Milky Way from flying apart.
• The Atacama Cosmology Telescope:
  • The telescope was commissioned at its site in late 2007.
  • It is a six-meter diameter telescope on Cerro Toco in the Atacama Desert of northern Chile.
  • Its goal is to study how the universe began, what it is made of, and how it evolved to its current state.