Stellar “Ghost” Discovered:  “Dark” Black Hole

Astronomers Detected a

Astronomers has for the first

 time discovered what may be a free-floating black hole by observing the brightening of a more distant star

As its light was

 distorted by the object's strong gravitational field — so-called gravitational microlensing.

The mass of the

 invisible compact object is between 1.6 and 4.4 times that of the sun.

Because astronomers think

that the leftover remnant of a dead star must be heavier than 2.2 solar masses in order to collapse to a black hole

The UC Berkeley researchers

 caution that the object could be a neutron star instead of a black hole.

Neutron stars are also

 dense, highly compact objects, but their gravity is balanced by internal neutron pressure, which prevents further collapse to a black hole.

your X-rays will also rise,” Nicolas Scepi, the new study’s co-author and a postdoctoral researcher at JILA

“Normally, if the ultraviolet rises