Environment & Science

NASA: There may be fewer black holes than previously thought

Artist concept of matter swirling around a black hole.
Artist concept of matter swirling around a black hole.
NASA/Dana Berry/SkyWorks Digital

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NASA announced Wednesday that scientists have discovered something never seen before in space: a neutron star beaming with the energy of 10 million suns.

Before now, it was thought only black holes could emit that kind of energy.

This means that some of the celestial bodies researchers once thought were black holes might actually be extremely dense, though powerful, neutron stars.

The discovery was made by the NuSTAR spacecraft, a school bus-sized space telescope that measures X-rays.

(An artists conception of NuSTAR in space. Image: NASA / JPL / Caltech)

NuSTAR was launched in June 2012 with the goal of studying distant black holes and other X-ray emitting objects in deep space.

Recently, the telescope examined a region called M82, also known as the Cigar Galaxy because it resembles an unlit stogie.

(An image of the Cigar Galaxy. Image: NASA, ESA, The Hubble Heritage Team.)

Caltech professor and NuSTAR investigator Fiona Harrison said her team noticed a powerful object that was emitting large amounts of X-rays.

Up until now, only black holes were believed to be capable of beaming out that kind of energy, she said.

However, this particular object was pulsating, or blinking with energy, something black holes cannot do.

Instead, it turns out this was a super powerful neutron star. No such object had been previously shown to emit such a large amount of energy. Like black holes, neutron stars are so dense their gravitational pull sucks in surrounding matter, releasing x-ray energy as it does. In this case, the neutron star in the Cigar Galaxy is gobbling up more matter and releasing more x-rays than any neutron star previously observed. 

"This little pulsar packs the power of a much, much bigger black hole," Harrison said. "It's something that theorists didn't think was possible."

Neutron stars are formed after a large star explodes in a supernova, leaving a core of material behind.

"They are incredibly dense," Harrison said. "A teaspoon full of a neutron star weighs more than the humans on Earth.

Astrophysicists will have to make further observations to better understand how these high-energy neutron stars operate.

While this discovery challenges what we know about deep space, Harrison said, it will ultimately help form a more accurate picture of how neutron stars, black holes and galaxies are related.