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Astronomers Discover Dragonfly 44, a Milky Way–sized Galaxy consisting of 99.99 percent Dark Matter

Dragonfly 44's mass is estimated to be one trillion times the mass of the Sun, which is similar to the mass of the Milky Way

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Little Cub galaxy
The Little Cub galaxy - so called because it sits in the Ursa Major or Great Bear constellation. Galaxy (Representational Image). Wikimedia

New York, August 27, 2016: An international team of astronomers has found a massive galaxy — about the size of the Milky Way — that consists almost entirely of dark matter.

The galaxy, Dragonfly 44, is located in the nearby Coma constellation and had been overlooked until last year because of its unusual composition. It is a diffuse “blob” about the size of the Milky Way, but with far fewer stars, the researchers said.

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“Very soon after its discovery, we realised this galaxy had to be more than meets the eye. It has so few stars that it would quickly be ripped apart unless something was holding it together,” said lead author Pieter van Dokkum from Yale University in New Haven, Connecticut.

Dragonfly 44’s mass is estimated to be one trillion times the mass of the Sun, which is similar to the mass of the Milky Way. However, only one-hundredth of one percent of that is in the form of stars and “normal” matter.

The dark galaxy Dragonfly 44. The image on the left is a wide view of the galaxy. Source: VOA news
The dark galaxy Dragonfly 44. The image on the left is a wide view of the galaxy.
Source: VOA news

The other 99.99 percent is in the form of dark matter — a hypothesised material that remains unseen but may make up more than 90 percent of the universe, the researchers reported in a paper published in the Astrophysical Journal Letters.

Van Dokkum’s team was able to get a good look at Dragonfly 44 thanks to the W.M. Keck Observatory and the Gemini North telescope, both in Hawaii.

Astronomers used observations from Keck, taken over six nights, to measure the velocities of stars in the galaxy.

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They used the eight-metre Gemini North telescope to reveal a halo of spherical clusters of stars around the galaxy’s core, similar to the halo that surrounds our Milky Way galaxy.

Star velocities are an indication of the galaxy’s mass, the researchers noted. The faster the stars move, the more mass its galaxy will have.

“Amazingly, the stars move at velocities that are far greater than expected for such a dim galaxy. It means that Dragonfly 44 has a huge amount of unseen mass,” co-author Roberto Abraham of the University of Toronto, explained.

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  • Kabir Chaudhary

    A great find by the astronomers in the field of space exploration. After reading about Dragonfly 44, i realised that the Universe have many hidden secrets and that humans will always be curious to explore it.

  • Manakas

    I’m curious as to what is in the center of the galaxy. Does it also have a supermassive black hole made out of regular matter or is there some equally dense dark matter equivalent of a black hole?

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  • Kabir Chaudhary

    A great find by the astronomers in the field of space exploration. After reading about Dragonfly 44, i realised that the Universe have many hidden secrets and that humans will always be curious to explore it.

  • Manakas

    I’m curious as to what is in the center of the galaxy. Does it also have a supermassive black hole made out of regular matter or is there some equally dense dark matter equivalent of a black hole?

Next Story

Study Reveals Solar Cells Can Retain Most Of Their Power Conversion Efficiency in Near Space

In the study, researchers from China's Peking University sent the devices fixed with PSCs into near space on a high-altitude balloon.

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solar energy
Perovskite solar cells (PSCs) are known for their potential of achieving higher efficiency and low production costs compared to traditional silicon solar cells. Pixabay

Chinese researchers have found that solar cells can retain most of their power conversion efficiency in near space, providing perspectives on the cells’ future application in space.

Perovskite solar cells (PSCs) are known for their potential of achieving higher efficiency and low production costs compared to traditional silicon solar cells.

These cells also have great potential for developing the new-generation energy technology for space application, but little research has been done to test the stability of PSCs in the extreme space environment, Xinhua news agency reported.

In the study, researchers from China’s Peking University sent the devices fixed with PSCs into near space on a high-altitude balloon.

energy
These cells also have great potential for developing the new-generation energy technology for space application, but little research has been done to test the stability of PSCs in the extreme space environment, Xinhua news agency reported. Piixabay

The balloon rose to near space at an altitude of 35 km, a region above Earth’s atmosphere where there is only a trace amount of moisture and ozone.

The region, considered to have “air mass zero” contains no atmospheric attenuation of solar radiation and therefore several high-energy particles and radiation, such as neutrons, electrons and gamma rays, originate from the galactic cosmic rays and solar flares.

solar cells
Chinese researchers have found that solar cells can retain most of their power conversion efficiency in near space, providing perspectives on the cells’ future application in space.
Pixabay

Also Read: Know About The Psychologists Team Helping To Prevent Farmers’ Suicides in Parts of Telangana

According to the findings, one type of PSCs used in the study retained more than 95 per cent of its initial power conversion efficiency during the test, the researchers reported in the journal Science China Physics, Mechanics and Astronomy.

They said the study is expected to play a crucial role in the future stability research of PSCs. (IANS)