GRAVITATIONAL WAVES

WHAT ARE GRAVITATIONAL-WAVES ?

Gravitational waves are one of the most interesting predictions of general relativity

• There are many potential sources of gravitational waves for our detectors, ranging from binary star systems to super-massive black hole mergers.

Gravitational-waves are ripples on space-time fabric produced by some of the most violent events in the cosmos, such as the collisions and mergers of massive compact stars.

NEWTON’S LAW OF UNIVERSAL GRAVITATION

We can see that the gravitational force is:

• Directly proportional to the masses of both objects.

• Inversely proportional to the distance between the objects.

The Law of Universal Gravitation allowed extremely accurate predictions of planetary orbits.

Newton - Gravity is “Action at a distance”.

Einstein - Gravity is space-time curvature.

Any mass/energy bends

space-time near it.

EINSTEIN’S THEORY OF GENERAL RELATIVITY?

Freely falling objects

follow the local

background curvature.

HOW ARE THE GRAVITATIONAL WAVES CREATED?

• When the curvature of the space varies rapidly, due to motion of the object(s), curvature ripples are produced.

• These ripples of the space-time are Gravitational-waves.

• These fluctuations propagate at the speed of light away from the source.

GRAVITATIONAL WAVES SHAPE

When a gravitational wave passes through, space is

stretched and squeezed alternately. The effect is opposite

in perpendicular directions: ‘+’ and ‘x’.

•Potential sources of detectable

gravitational waves include binary stars

systems composed of

•white dwarfs

•neutron stars

•black holes

On February 11, 2016, the LIGO Scientific

Collaboration and Virgo Collaboration

teams announced that they

had directly detected gravitational

waves from a pair of merging black

holes using the Advanced LIGO

detectors.

GRAVITATIONAL WAVES SOURCES

LIGO - OBSERVATION OF GRAVITATIONAL WAVES FROM A

BINARY BLACK HOLE MERGER

• We report on two major scientific breakthroughs involving key predictions of Einstein’s theory:

• the first direct detection of gravitational waves

• the first observation of the collision and merger of a pair of black holes.

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Black holes are one of the most powerful forces in the Universe.

A black hole does not have a surface, like a planet or star.

It is a region of space where gravity is so strong that even light cannot escape from it.

Even though we cannot see a black hole, it does have three properties that can be measured:

Mass

Electric charge

Speed of rotation

WHAT IS A BLACK HOLE?

PARTS OF BLACK HOLES

•The Singularity: This is the center of

the black hole where all the mass of the black hole has

been compressed down to nearly zero volume. The

singularity is where the material pulled into the black hole

is crushed until it takes up no space and creates an

enormous gravitational force.

•The Event Horizon: This is the "point of no return". At the

event horizon, objects and light disappear into the

singularity and are never seen again.

•The Accretion Disk: Swirling disk of hot gas, dust

and stellar debris. Material in the accretion disk orbits the

black hole spiraling closer until it crosses the event

horizon.

BLACK HOLES PROPERTIES

Even though we cannot see a black hole, it does have three properties that can be measured:

• Mass

• Electric charge

• Speed of rotation

A black hole is black because its

gravitational pull is so dense that it traps

light.

HOW ARE BLACK HOLES DETECTED?

• Black holes are detected as surrounding material in the accretion disk swirl around the black hole so fast, that they heat up and emit X-rays. These X-rays can be detected from Earth.

GRAVITY WAVES

• Gravity waves are different than the gravitational waves.

• Gravitational Waves are created by cataclysmic galactic events

• Gravity Waves are created by interactions between the atmosphere and gravity

• The layers that make up the atmosphere change temperature and pressure as you rise or fall. When one of the layers hits something like, a mountain, they push up against it, but gravity pulls them back down. The effect ripples through the other layers, creating waves all the way down.

GRAVITY WAVES OVER A LAKE

• Over oceans and other bodies of water, satellites can pick up the atmosphere's rippling on the surface. Here, you can see the waves in the form of white wrinkles over Lake Superior.

RESOURCES

https://www.youtube.com/watch?v=72AQsQ2v5cA

https://www.youtube.com/watch?v=hhbMpe17fzA\https://www.youtube.com/watch?v=dplIZUX7tyU&ebc=ANyPxKoa1kskr2o0Zq

UCXj3MSNXsIKzQR_6GIIeQ4w1ewJUrVIJuO8hichDeaZQZ6pNmy2H2a0-95cUipSAu3-QFJ5m52MMEGw

https://www.youtube.com/watch?v=jUJXQsE43IY

http://www.ligo.org/science/GW-IFO.php

http://phys.org/news/2016-02-black-holes-meetinside-cataclysms-gravitational.html