Hubble Black Holes - NASA Science

How do you find an invisible object in the vast darkness of space that traps light?

The answer, as astronomers know, is that you watch for the way things move around it.

And black holes, the universe’s most voracious consumers of mass, have a famously attention-grabbing impact on all kinds of things. Black holes can be detected and observed by the way matter dances around them ― from the stars that orbit them to the disks of material that swirl around them before being devoured. Hubble, with its keen resolution and clear view of the cosmos, has played an essential role in identifying, observing, and solving some of the many mysteries around black holes.

Bright, golden light in the upper-left corner. It diffuses out from the point gradually giving way to a darker background in the lower-right corner. Emanating from the bright point is a clumpy stream of white gas that stretches toward the lower-right corner.

Streaming out from the center of M87 like a cosmic searchlight is one of nature’s most amazing phenomena: a black-hole-powered jet of subatomic particles traveling at nearly the speed of light. In this Hubble image, the blue jet contrasts with the yellow glow from the combined light of billions of unresolved stars and the point-like clusters of stars that make up this galaxy.

NASA and the Hubble Heritage Team (STScI/AURA)

Black holes are invisible objects of immense density whose gravity is so overpowering that not even light can escape them, born when a vast amount of matter collapses into a point of infinite density.

When a massive star dies, the tug-of-war between gravity and the outward push of photons generated by the star’s fusion ends. The star’s outer layers are cast explosively into space while the star’s core collapses under its own gravity. Often this core will become a small, dense object of tightly packed neutrons, called a neutron star. But if the core is massive enough, its gravity compresses everything to a point that becomes a black hole.

Black holes consist of two main components: the singularity, where mass has been crushed to a point; and the event horizon, beyond which nothing ― not even light ― can escape the black hole’s intense gravitational pull.

But before they eat, black holes pull matter into a fast-moving whirlpool disk whose superheated gas emits flares of x-rays and ultraviolet light. Hubble’s spectroscopic observations of such disks proved the existence of supermassive black holes and went on to show that they reside at the hearts of most galaxies. Its ability to resolve individual stars in tightly-packed groups of stars called globular clusters has allowed it to find black hole candidates by measuring their cosmic neighbors’ speedy orbits. And its ultraviolet-detecting capabilities has enabled it to spy emissions from black holes’ disks.

Stellar-mass black holes form from the collapse of a massive star or the addition of mass to a neutron star ― either from the collision of neutron stars or by gravitationally drawing mass from a companion object. Supermassive black holes live in the hearts of galaxies and their origins are still uncertain, though astronomers suspect they begin from the collapse of supermassive stars or massive clouds of gas in the early universe and then grow by merging. Intermediate-mass black holes, the stage between the two, have been difficult to find and are thought to form from collisions between stellar-mass black holes.

Black holes are messy, violent, and fascinating. They tear things apart ― but they also build, thought to play a significant role in the way galaxies form and evolve. Astronomers know what black holes are, but with Hubble’s help they continue to explore how they work and where they come from.

For more than 30 years, the Hubble Space Telescope has uncovered the mysteries of the universe. One of the mysteries that Hubble helped us understand is black holes.

NASA Goddard Space Flight Center, Director & Producer: James Leigh

A disk in orange-red, and yellow-white. A yellow white point at image center surrounded by a deep orange-red disk that is ringed by yellow-white and then more orange-red.

Hubble captured this image of a giant disk of cold gas and dust fueling a possible black hole at the core of the galaxy NGC 4261. Estimated to be 300 light-years across, the disk is tipped enough (about 60 degrees) to provide astronomers with a clear view of its bright hub, which presumably harbors the black hole. The dark, dusty disk represents a cold outer region which extends inwards to an ultra-hot accretion disk within a few hundred million miles of the suspected black hole.

Walter Jaffe/Leiden Observatory, Holland Ford/JHU/STScI, and NASA

A massive spiral galaxy fills the image. A bright, yellow galactic core glows at the center, surrounded by spiral arms studded with pink stars and dark lanes of dust.

Spiral galaxy NGC 4951, located roughly 50 million light-years away from Earth, is classified as a Seyfert galaxy, an extremely energetic type of galaxy with an active galactic nucleus (AGN). AGNs are powered by supermassive black holes at their center. As matter whirls into the black hole, it generates radiation across the entire electromagnetic spectrum, making the AGN shine brightly. Seyfert galaxies are unique among AGNs because their galaxies are visible ― typically for other AGNs, the nuclei are so bright that they drown out their host galaxies.

NASA, ESA, and D. Thilker (The Johns Hopkins University); Image Processing: Gladys Kober (NASA/Catholic University of America)

Star at center of image brightens and dims. Just to the right of it is another bright star. At left, center three stars trail toward the bottom center of the image.

This time-lapse of a set of four Hubble photos capture the gravitational effects of an invisible black hole drifting through our galaxy. The gravity of a foreground object passing in front of a star located far behind it warps space, momentarily bending and amplifying the light of the background star. Astronomers use the phenomenon, called gravitational microlensing, to study stars and exoplanets. Here, as the black hole passed between us and the distant star, its gravitational field amplified the starlight, causing the background star to momentarily brighten, as first seen by Hubble in August 2011. The star then faded back to normal brightness.

NASA, ESA, and Kailash Sahu (STScI); Animation: Joseph DePasquale (STScI)