They have never found a force carrier for gravity. The elusive gravitons. Through the Wormhole With Morgan Freeman s1e1: Is There a Creator? Science 2010
Gravity slows time, and this is key to one form of time travel. Through the Wormhole with Morgan Freeman s1e3: Is Time Travel Possible?
We feel it every moment of our lives: but for physicists it is the oldest unsolved mystery in the cosmos. Why does gravity make everything attract? … Could gravity be another force in disguise? Through the Wormhole with Morgan Freeman s5e2: Is Gravity an Illusion?
Gravity is the hardest problem in physics. ibid.
Gravity ... It will accelerate to land at a constant rate of 0.98 meters per second per second. This is a fundamental law on our planet. Professor Marcus du Sautoy, The Code I: Numbers BBC 2011
Guth: Gravity can act in reverse. Professor Brian Greene, Beyond The Cosmos: Multiverse, National Geographic 2012
What if gravity and acceleration are really the same thing? Inside Einstein’s Mind: The Enigma of Space and Time, BBC 2015
What if space/time is shaped by matter? And that’s what we feel as gravity. ibid.
Nash had an idea about ‘gravity, friction and radiation' as he later recalled. The friction he was thinking of was the friction that a particle, say a photon, might encounter as it moved through space due to its fluctuating gravitational field interacting with other gravitational fields. Sylvia Nasar, A Beautiful Mind
It’s the strangest idea in the whole of science. It emerged by accident from bizarre experiments. Scientists resisted it. But a maverick would force them to take it seriously. The idea means we live in a giant bubble. Parallel Universes, National Geographic
Some of the world’s most respected scientists claim these other worlds may actually exist. ibid.
Some exist far beyond the further edge of our visible universe, others hang out in a mysterious landscape full of dark energy called the Multiverse, and others are right here in the same space we are all living, but we can’t see them obviously. ibid.
You might not want to meet your other self. ibid.
[Hugh] Everett wrote what’s become the definitive argument for parallel universes called Many Worlds. ibid.
An infinite number of other realities. ibid.
It sculps the universe. It warps space and time. It’s a fundamental force of nature. Jim Al-Khalili, Gravity and Me: The Force that Shapes Our Lives, BBC 2017
Something fundamental to all falling objects – they accelerate. ibid.
F = G M1 x M2
---------
R² ibid.
I really have shrunk by just over half an inch over the course of the day. ibid.
You could be forgiven for thinking of gravity as vastly powerful. Indeed every moment of our lives is shaped and defined by gravity. The Entire History of the Universe e10: Why is Gravity So Weak? 2021
It is weaker even than the so-called Weak Force. ibid.
Gravity’s relative weakness has baffled scientists for years. ibid.
The existence of gravitational waves implies that gravity is not simply a force between individual objects but a field that extends through all space and time. ibid.
Discovery have joined forces with Stephen Hawking’s fellow researchers in Cambridge … Universe Unravelled with the Stephen Hawking Centre s1e1: Asking the Big Questions (short), DiscoveryPlus 2020
‘I want to know why the universe exists.’ ibid. Hawking to colleague
‘5 questions he helped solve: 1) Did the universe have a beginning in time? 2) Are black holes unique? 3) What happens when black holes collide? 4) Do black holes live for ever? 5) Do we know where galaxies come from?’ ibid.
David Scott, Apollo 15: With that hammer and the feather he was about to prove a prediction that was made 400 years earlier by this man: Galileo Galilei … They landed at exactly the same time. Universe Unravelled with the Stephen Hawking Centre s1e2: Relativity: Newton’s Law (short)
F = G Mm/r2 … Newton’s Law of Gravitation is simple but it’s hugely effective.
Our understanding of Gravity fundamentally changed with the radical theories of one world-famous scientist: Einstein. Universe Unravelled with the Stephen Hawking Centre s1e3: Einstein’s Very Special Theory (short)
14th September 2015: The first ever proof that black holes existed … The merger of a black-hole binary … generated gravitational waves. Universe Unravelled with the Stephen Hawking Centre s1e4: What are Gravitational Waves? (short)
These waves are very difficult to detect. ibid.
We’ll be discovering the science behind the amazing machines that allowed us to detect these waves, and how we can identify where they come from. Universe Unravelled with the Stephen Hawking Centre s1e5: Gravitational Waves (short)
Neutron stars: What happens when the collide? And what we learned when we detected the first neutron star collision. Universe Unravelled with the Stephen Hawking Centre s1e6: What Have We Observed So Far? (short)
We now have a brand-new wave of measuring the evolution of the universe: the Hubble Constant. ibid.
When large stars die … 20x more massive that our sun = Not even light can escape the gravitational pull … Universe Unravelled with the Stephen Hawking Centre s1e7: What Exactly is a Black Hole? (short)
How we can see a black hole and what we can learn from observations … April 2019: An actual picture of a black hole for the first time ever. The image agrees with the predictions made by Einstein’s Theory of General Relativity … Universe Unravelled with the Stephen Hawking Centre s1e8: How Can We See a Black Hole? (short)
They can be described just by their mass and their spin. Universe Unravelled with the Stephen Hawking Centre s1e9: Do Black Holes Live Forever (short)
They emit what is called Hawking radiation. ibid.
Cosmic Microwave Background: The detection of a mysterious anomaly sixty years ago was able to take us right back to the beginning of the universe … Did the universe have a beginning. Universe Unravelled with the Stephen Hawking Centre s1e10: Black Holes and the Big Bang (short)
One of the darkest mysteries of the universe … we’ve only just begun to explore. Universe Unravelled with the Stephen Hawking Centre s1e11: Shining Light on Dark Matter (short)
What exactly is dark matter? We don’t really know yet. ibid.
What is the universe expanding into? ibid.
How we discovered our universe is expanding ... ‘The space between the galaxies is expanding.’ Universe Unravelled with the Stephen Hawking Centre s1e12: Expanding Universe, Big Bang (short)
It started with two scientists, a telescope and some pigeon droppings. Universe Unravelled with the Stephen Hawking Centre s1e13: A Baby Picture of the Universe (short)
The glow: This was the Cosmic Background Radiation or CBR. ibid.
Not only is it expanding, this expansion at present is accelerating. And that acceleration cosmologists believe also happened in the early universe. Universe Unravelled with the Stephen Hawking Centre s1e14: What is Inflation? (short)
CMB provides compelling evidence for the Big Bang … It offers insight into how the large structures we see today came into being. Universe Unravelled with the Stephen Hawking Centre s1e15: Where Did We Come From? (short)
There was a slightly higher density of matter in some places than there was in others … Tiny fluctuations would evolve under the influence of gravity. ibid.
This extra gravitational effect comes from dark matter. Universe Unravelled with the Stephen Hawking Centre s1e16: Can We See Dark Matter? (short)
Cosmic pie: 69% dark energy, 26% dark matter, 5% ordinary matter. Universe Unravelled with the Stephen Hawking Centre s1e17: Cosmic Pies (short)