Giant Black Hole Inside Small Galaxy Surprises Scientists

A computer simulation of the collision of two black holes detected by the Laser Interferometer Gravitational-Wave Observatory, or Ligo, in Washington in February, 2016. Photo: Reuters/Caltech/MIT/Ligo Laboratory
A computer simulation of the collision of two black holes detected by the Laser Interferometer Gravitational-Wave Observatory, or Ligo, in Washington in February, 2016. Photo: Reuters/Caltech/MIT/Ligo Laboratory
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Giant Black Hole Inside Small Galaxy Surprises Scientists

A computer simulation of the collision of two black holes detected by the Laser Interferometer Gravitational-Wave Observatory, or Ligo, in Washington in February, 2016. Photo: Reuters/Caltech/MIT/Ligo Laboratory
A computer simulation of the collision of two black holes detected by the Laser Interferometer Gravitational-Wave Observatory, or Ligo, in Washington in February, 2016. Photo: Reuters/Caltech/MIT/Ligo Laboratory

A tiny galaxy orbiting at the outskirts of the Milky Way appears to have a giant black hole at its center, comparable to that of the much larger Milky Way itself, and scientists are surprised.

The Leo I dwarf galaxy is some 820,000 light-years from Earth, and astronomers believe its mass was about 15 to 30 million times the mass of our sun. That's tiny compared to the Milky Way, which is estimated to weigh as much as 1.5 trillion suns and whose disk is over 100,000 light-years wide.

However, the study published in the latest issue of the Astrophysical Journal, unexpectedly found that at the heart of the little Leo I sits a black hole that is nearly as large as the one at the heart of the entire Milky Way. The discovery defies expectations as astronomers believed giant black holes grow from collisions between galaxies and should correspond with the galaxy's size.

"There is no explanation for this kind of black hole in dwarf spheroidal galaxies," María José Bustamante, an astronomy researcher at the University of Texas, and lead author of the new paper, said in a statement quoted by the Live Science website.

The discovery came as scientists originally set out to measure the amount of dark matter in Leo I using the Virus-W instrument on the University of Texas' 2.7-meter Harlan Telescope.

Virus-W measures the motion of stars in small galaxies around the Milky Way and infers the amount of dark matter in those galaxies from those motions.

Dark matter is the completely invisible material that resists gravity. Scientists can measure its concentrations in the universe based on its effects on orbits and velocities of nearby stars. The more dark matter in the star's orbit, the faster it travels.

When the team ran data gathered in the observations through their computer models, they found that Leo I appears to have basically no dark matter but a black hole at its center as heavy as 3 million suns. These findings surprised the scientists as the Sagittarius A* black hole at the center of the Milky Way is only 25% larger.



Sunken WWII Japanese Warship Found Off Solomon Islands

A team from the US non-profit Ocean Exploration Trust discovered the Imperial Japanese Navy destroyer Teruzuki. Photo: Ocean Exploration Trust
A team from the US non-profit Ocean Exploration Trust discovered the Imperial Japanese Navy destroyer Teruzuki. Photo: Ocean Exploration Trust
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Sunken WWII Japanese Warship Found Off Solomon Islands

A team from the US non-profit Ocean Exploration Trust discovered the Imperial Japanese Navy destroyer Teruzuki. Photo: Ocean Exploration Trust
A team from the US non-profit Ocean Exploration Trust discovered the Imperial Japanese Navy destroyer Teruzuki. Photo: Ocean Exploration Trust

An international research team has located a Japanese World War II destroyer on the deep seabed off Solomon Islands as the 80th anniversary of the war's end approaches.

A team from the US non-profit Ocean Exploration Trust discovered the Imperial Japanese Navy destroyer Teruzuki at a depth of more than 800 meters (2,625 feet) off the small island nation northeast of Australia, AFP reported.

A video image of the wreck shows parts of the 134-meter (440-foot) Teruzuki, which was torpedoed by the US military in 1942, illuminated by lights from the research team's underwater drones.

The footage shows red paint on the hull, corroded gun barrels and the warship's massive stern.

Commissioned in 1942, the Teruzuki was designed for screening aircraft carriers from aerial attacks, the exploration group said.

However, the Teruzuki, which means "Shining Moon" in Japanese, was hit by US torpedoes just months into its service.

Nine sailors were killed but most of the crew members survived, the Ocean Exploration Trust said.

Teruzuki's stern was found more than 200 meters (660 feet) from the hull and was located by high-resolution sonar scans, it said.

The discovery was made while the team used drones to survey the area in the hope of finding unidentified shipwrecks or other items.