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Sir Isaac Newton - Blog Posts
Gravitational Waves in the Space-Time Continuum
Einstein's Theories of Relativity
Einstein has two theories of relativity. The first is The Theory of Special Relativity (1905). This is a theory of mechanics that correctly describes the motions of objects moving near the speed of light. This theory predicts that mass increases with velocity. The equation is E=MC^2 or Energy = Mass × Speed of Light ^2.
In 1916, Einstein proposed the Theory of General Relativity, which generalized his Theory of Special Relativity and had the first predictions of gravitational waves. It implied a few things.
Space-Time is a 4-Dimensional continuum.
Principle of equivalence of gravitational and inertial mass.
This suggests that Mass-Energy distorts the fabric of space-time in a predictable way (gravitational waves). It also implies
Strong gravitational force makes time slow down.
Light is altered by gravity
Gravity in strong gravitational fields will no longer obey Newton's Inverse-Square Law.
What is Newton's Inverse-Square Law?
Newton's Inverse-Square Law suggests that the force of gravity between any two objects is inversely proportional to the square of the separation distance between the two centers.
Stephen Hawking's Theory of Everything
Stephen Hawking's Theory of Everything is the solution to Einstein's equation in his Theory of General Relativity. It says that the mass density of the universe exceeds the critical density.
Critical Density: amount of mass needed to make a universe adopt a flat geometry.
This theory states that when the universe gets too big it will crash back into its center in a "Big Crunch" creating giant black hole. The energy from this "Big Crunch" will rebound and create a new "Big Bang".
Big Crunch: hypothetical scenario for the end of the known universe. The expansion of the universe will reverse and collapse on itself. The energy generated will create a new Big Bang, creating a new universe.
Big Bang: Matter will expand from a single point from a state of high density and matter. This will mark the birth of a new universe.
Basic Facts about Gravitational Waves
Invisible "ripples" in the Space-Time Continuum
Travel at the speed of light
186,000 miles per second / 299,337.984 Kilometers per second
11,160,000 miles per minute / 17,960,279.04 Kilometers per minute
669,600,000 miles per hour / 1,077,616,742.4 Kilometers per hour
There are four (4) defined categories
Continuous
Stochastic
Burst
Compact Binary Inspiral
What is LIGO?
The first proof of the existence of gravitational waves came in 1974. 20+ years after Einstein's death.
The first physical proof came in 2015, 100 years after his theory was published. The waves were detected by LIGO.
LIGO- Laser Interferometer Gravitational-Wave Observatory
The waves detected in 2015 came from 2 black holes that collided 1.3 billion years ago in the constellation Hydra. 1.3 billion years ago multicellular life was just beginning to spread on Earth, it was before the time of the dinosaurs!
Continuous Gravitational Waves
Produced by a single spinning massive object.
Caused by imperfections on the surface.
The spin rate of the object is constant. The waves are come at a continuous frequency.
Stochastic Gravitational Waves
Smalles waves
Hardest to detect
Possibly caused by remnants of gravitational radiation left over from the Big Bang
Could possibly allow us to look at the history of the Universe.
Small waves from every direction mixed together.
Burst Gravitational Waves
Never been detected.
Like ever.
Never ever.
Not once.
Nope
No
N E V E R
We don't know anything about them.
If we learn about them they could reveal the greatest revolutionary information about the universe.
Compact Binary Inspiral Gravitational Waves
All waves detected by LIGO fall into this category.
Produced by orbiting pairs of massive and dense objects. (Neutron Stars, Black Holes)
Three (3) subclasses
Binary Neutron Star (BNS) // Two (2) Neutron Stars colliding
Binary Black Hole (BBH) // Two (2) Black Holes colliding
Neutron Star- Black Hole Binary (NSBH) // A black hole and a neutron star colliding
Each subclass creates its own unique wave pattern.
Waves are all caused by the smae mechanism called an "inspiral".
Occur over millions of years.
Over eons the objects orbit closer together.
The closer they get, the faster they spin.
Sources Used:
On The Shoulders Of Giants by Stephen Hawking
Oxford Astronomy Encyclopedia
@watch-out-idiot-passing-through @nasa