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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