Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


The Last Cry Of Matter


‘Black holes’ are truly black. When an object gets within a certain distance from a black hole, it will get swallowed forever with no chance to escape. That includes light, which means that black holes do not shine.

How do astronomers detect black holes if they are unable to see them? Well, to be precise, astronomers do not detect black holes. But they do detect the phenomena that can only be explained by the existence nearby of objects that match the description of black holes!

The strong gravitational attraction of a black hole affects the motion of nearby objects. When astronomers see a star circling around something, but they cannot see what that something is, they may suspect it is a black hole, or a neutron star - the ultra-dense ‘corpse’ of a star.

Astronomers can even infer the mass of a black hole by measuring the mass of the star and its speed. The same kind of calculation can be done whith supermassive black holes that lurk at the centre of many galaxies, including our own galaxy, the Milky Way.

In the Milky Way, observations have revealed the existence of stars and gas moving very fast near the centre, a behaviour that can only be explained if a mass of several million times that of the Sun is at the centre of the galaxy.
Such mass has to be concentrated within a radius of only 10 light-days - roughly 40 times times the distance from the Sun to Pluto - and is most likely to be a black hole.

In fact, at the very centre of our galaxy, radio and X-ray telescopes have detected a powerful source called ‘Sagittarius A’, identified as the candidate to be this massive black hole.
This idea has recently received strong support, with the measurement for the first time of the orbit of a star that approaches this mysterious object to within 17 light-hours - only three times the distance between the Sun and Pluto - while travelling at speeds of than 5000 kilometres per second!

Shining to death

Another piece of evidence in favour of the idea of supermassive black holes in the centre of galaxies is the existence of quasars, discovered in 1967. Quasars are very distant and very luminous at the same time - the most luminous objects in the Universe.

To explain the incredible amount of energy they must release, astronomers also need black holes: just before disappearing into a black hole, the matter being swallowed heats up and emits great amounts of energy - its ‘last cry’. So quasars are believed to be caused by black holes with masses of one million to several billion times the mass of the Sun.

The ‘last cry’ of matter about to be swallowed is best detected with x-ray and gamma-ray telescopes, because the energy released is given off in the form of hard x-rays. In fact, ESA’s orbiting observatories XMM-Newton and Integral have already shown their skills in studying black holes in several discoveries.

For example, XMM Newton has recently discovered a small black hole whirling in our galaxy, in the Ara constellation of the southern sky. Integral has detected what could be the first significant hard x-ray emission from the black hole in the centre of our galaxy.

Guido De Marchi | ESA
Further information:

More articles from Physics and Astronomy:

nachricht Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)

nachricht Finding the lightest superdeformed triaxial atomic nucleus
20.10.2016 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

New method increases energy density in lithium batteries

24.10.2016 | Power and Electrical Engineering

International team discovers novel Alzheimer's disease risk gene among Icelanders

24.10.2016 | Life Sciences

New bacteria groups, and stunning diversity, discovered underground

24.10.2016 | Life Sciences

More VideoLinks >>>