Dose a black hole have mass and if so how do we mesure it?

Answer 1

A black hole is a supermassive star that collapsed into itself, so it has mass. I would think the only way we could measure it is we could get close enough to tell how much of a gravity pull it was exerting. If we knew the gravity it was pulling with, we could determine how much mass is needed.

Answer 2

Black holes have density; it's what makes them so incredible. The centre of the black hole, the singularity, is smaller than one of the keys I'm typing with now, but there is so much mass packed into that small area that it creates a massive gravitational pull.
In fact, the large black circle that we call a 'black hole' is only the reach of that singularity, and is called the Accretion disk. On the outside of the disk you could sit quite happily and admire the blackness before you (not literally but at least you wouldn't die) however, theoretically, if you passed into the disk; over the Event Horizon (the edge) you'd be sucked in so fast it would seem like you were still there to anyone else.

Tiberius' Top Tip: Try not to think about what happens when you pass the Event Horizon. It cannot be anything nice.

Answer 3

There are a few ways that black holes can be formed; As the direct result of a gravitational collapse of a star, or by collision between two neutron stars (which are very rare). Once this happens, the collapsed energy can generate enough pressure to produce black holes, because singularities are the most radically transformed state of matter known to physics (if you can still call it matter) and the force which resists this level of compression, neutron degeneracy pressure, is extremely strong. Remnants exceeding 5 solar masses (5x the mass of the sun) are produced by stars which were over 20 solar masses before the collapse (the rest of the mass is usually blown into space by the supernova triggered by the collapse). According to general relativity, a black hole's mass is entirely compressed into a region with zero volume, which means its density and gravitational pull are infinite, and so is the curvature of space-time which it causes. These infinite values cause most physical equations, including those of general relativity, to stop working at the center of a black hole. So physicists call the zero-volume, infinitely dense region at the center of a black hole a "singularity". In order to sum it all up, Yes, black holes have mass. If it lacked mass, its gravitational pull would be non-existant. The only way we know how to measure it currently, is through equations, variables, and observations. Eventually, we may reach a point when our technology has advanced, allowing to send probes inside of the black hole, allowing us to gather almost exact data. But for now, its all guesstimation. (Sorry it was so long)

Answer 4

A black hole has the mass of whatever collapsed to form it, plus everything it's accreted since. The mass of super black holes in the centers of galaxies is determined by the orbital radius and speed of stars in its vicinity. Such speed is determined by the Doppler shift of the stars' spectra. A stellar black hole's mass could be measured in an analogous manner by the velocity of its accretion disk of in-falling matter.

Answer 5

Yes, it has mass. Any massive celestial object also is a source of gravitational potential. This locally affects the structure of the universe per Einstein's equation. However, a suitable measurement can be determined simply by the graviational influence of the body. At distances well beyond the corona of the BH, the mass is determined just as you would for any compact object, like a normal star. You can also measure it by its structure (angular momentum, ...) or its local gravitational lensing.

Answer 6

MASS OF THE BLACK HOLE

mass black hole (IMBH) is a black hole whose mass is significantly more than stellar black holes (a few tens of the mass of the Sun) yet far less than supermassive black holes (a few millions of the mass of the Sun).

There is less evidence for their existence than for the other two types. Some ultra-luminous X ray sources (ULXs) in nearby galaxies are suspected to be IMBHs, with masses of a hundred to a thousand solar masses.[1] The ULXs are observed in star forming regions (e.g., in starburst galaxy M82[2], see external links for beautiful pictures of this galaxy), and are seemingly associated with young star clusters which are also observed in these regions. However only a dynamical mass measurement from the analysis of the optical spectrum of the companion star can unveil the presence of an IMBH as the compact accretor of the ULX.

Additional evidence for the existence of IMBHs can be obtained from observation of gravitational radiation, emitted by the compact remnant that orbits the IMBH.[3]

However it is not clear how such a black hole would form. On the one hand, they are too massive to be formed by the collapse of a single star, which is how the stellar black holes are thought to form. On the other hand, their environments lack the extreme conditions—i.e., high density and velocities observed at the centers of galaxies—which seemingly lead to the formation of supermassive black holes. There are two popular formation scenarios for IMBHs. The first, is the merging of stellar mass black holes and other compact objects by means of gravitational radiation. The second one is the runaway collision of massive stars in dense stellar clusters and the collapse of the collision product into an IMBH.

In November 2004 a team of astronomers reported the discovery of GCIRS 13E, the first intermediate-mass black hole in our galaxy, orbiting three light-years from Sagittarius A*.[4] This medium black hole of 1,300 solar masses is within a cluster of seven stars, possibly the remnant of a massive star cluster that has been stripped down by the Galactic Centre. This observation may add support to the idea that supermassive black holes grow by absorbing nearby smaller black holes and stars. However, recently, a German research group claimed that the presence of an IMBH near the galactic center is doubtful.this conclusion is based on a dynamical study of a small star cluster in which should reside the suspected intermediate mass black hole. The debate on the real existence of intermediate mass black holes is still open.

More recently, in January 2006 a team led by Prof. Philip Kaaret of the University of Iowa, Iowa City announced the discovery of a quasiperiodic oscillation from an intermediate-mass black hole candidate located using NASA's Rossi X-ray Timing Explorer. The candidate, M82 X-1, is orbited by a red giant star that's losing its atmosphere into it.[6] Neither the existence of the oscillation nor its interpretation as the orbital period of the system are fully accepted by the rest of the scientific community. While the interpretation is quite reasonable, the periodicity is claimed based on only about 4 cycles, meaning that it is quite possible for this to be random variation. If the period is real, it could be either the orbital period, as suggested, or a super-orbital period in the accretion disk, as is seen in many other systems.

Answer 7

A black hole has a HUGE mass. It's usually measured by the distortion of light passing close by it.

Remember, it has such a large mass that it's gravity is enough to pull in even light, so it will distort anything passing by it (provided it doesn't pull it in). The level of distortion would give us an idea of it's gravity - which in turn would indicate it's mass.

Answer 8

Yes , an enormous amount. So much that the gravity is enough so that even light cannot escape from the gravity well.
Its mass can be calculated by the gravitational effect on a relatively nearby body {star}

Answer 9

It depends on how you define "black hole"...

Does a black hole include the matter at the center?

OR

Is a black hole the EFFECT that the mass has on everything that comes into it's proximity?
.

Answer 10

As its a collapsed star or sun or whatever the technical term is then it will, in all likelihood have to have some sort of mass, as for measuring it -- carefully would be my advice....