Specifically, astronomers have been studying star SO-2 which is hurtling around the supermassive black hole at the centre of our galaxy, completing its oval-shaped orbit in just 16 years.
Star SO-2 has the fastest ballistic orbit yet measured, travelling at almost 3% of the speed of light at its closest approach to the supermassive black hole.
Of course, the first image of Sagittarius A*, the supermassive black hole at the centre of our Milky Way Galaxy, was released last year.
What you see in the image is a central dark region where the hole resides, circled by the light coming from super-heated gas accelerated by immense gravitational forces. For scale, the ring is roughly the size of Mercury's orbit around our Sun.
The supermassive black hole at the centre of our galaxy is quiescent, so is presently emitting no jets.
However, the first supermassive black hole to be imaged was the one at the heart of distant galaxy M87, and it is still active.
A jet of matter stretching to around 5,000 light years from the centre of the M87 galaxy is visible in the attached telescopic image.
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Speaking of, there was a Geocities page (or maybe it was Angelfire) circa 1999 asserting that LIGO was bogus science and a waste of the money being spent on it. I've tried my best to find it to no avail. Archive.org and maybe others have allegedly saved many Geocities pages, but I don't know if that one got saved.
Veering off-topic, there was also a Geocities page asserting that the sound of the then-new Digital TV signal was not as good as the original analog because ... the digitizing made it into a stair-step wave. I saw the proprietor of the page on a forum (Clark Howard consumer forum) and conversed with him a bit. He had no clue about the psychoacoustic compression used in such a broadcast, and was just repeating the analog audiophile BS he had read elsewhere.
Here's something that may be surprising (!):
I found it in this article on this remarkable site:
https://wikenigma.org.uk/content/physics/cosmology/intergalactic_stars
Half of stars lurk outside galaxies
https://www.nature.com/articles/nature.2014.16288I found it in this article on this remarkable site:
https://wikenigma.org.uk/content/physics/cosmology/intergalactic_stars
A mass with a velocity v has a relativistic energy determined by:Galu said:
Code:
K.E. = M.{1/(sqrt(1 - (v/c)^2) - 1}.c^2M: is the rest mass
v: the velocity
c: the speed of light
The extra mass is not only a resistance to motion but it does contain energy according to E = m.c^2. It appears, there is more to explain mass.
@ benb
Lee Marvin famously sang of being born under a Wand'rin' Star.
And stars do wander about the Universe!
In fact, one of these wanderers, a star named Gliese 710, will pass within 10,000 AU of our solar system in around 1.4 million years time.
It is estimated that a nomadic star passes close by our solar system every 50,000 years or so, one such being Scholz's star which passed through the Oort Cloud 70,000 years ago.
Lee Marvin famously sang of being born under a Wand'rin' Star.
And stars do wander about the Universe!
In fact, one of these wanderers, a star named Gliese 710, will pass within 10,000 AU of our solar system in around 1.4 million years time.
It is estimated that a nomadic star passes close by our solar system every 50,000 years or so, one such being Scholz's star which passed through the Oort Cloud 70,000 years ago.
And what about wandering black holes? 😱
Astronomers estimate that 100 million black holes roam among the stars within our Milky Way galaxy.
Stellar-mass black holes are usually found with companion stars, but Hubble has found one that is wandering around in a spiral arm of our galaxy all on its own.
The gravitational microlensing of a background star caused by the wandering black hole has allowed astronomers to estimate its mass as seven times the mass of the Sun.
Astronomers estimate that 100 million black holes roam among the stars within our Milky Way galaxy.
Stellar-mass black holes are usually found with companion stars, but Hubble has found one that is wandering around in a spiral arm of our galaxy all on its own.
The gravitational microlensing of a background star caused by the wandering black hole has allowed astronomers to estimate its mass as seven times the mass of the Sun.
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As observation technique improves, I have a feeling that the 85% estimate for dark matter would be revised considerably within a few years.
A pretty good approximation of the above equation* is E = mc^2 + ½mv^2, where m is the rest mass.
Writing it like this makes the separation of relativistic energy into rest mass energy and classical kinetic energy apparent.
*Good up to speeds as high as 20% that of light.
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Maybe there is no such fundamental thing as mass. It maybe just an emergent property, not a thing by itself. I've seen proposals on youtube somewhere that mass is simply an observed behaviour/property of energy. Wherever you have energy you have the potential to see behaviour that can be described by 'laws' we've invented that use the term mass where mass = E/c*c. There is no actual mass, it's not a fundamental property and we can replace the term mass in all of our laws of physics with E/c*c as being more representative.
The proton is a good case in point. It's so-called rest mass predominantly comes from the energy of motion and binding energy of the gluons (a mass-less force carrying particle). The apparent rest mass of a proton is thus an emergent property of the energy within it and not a fundamental property.
It's no coincidence that internal mass and gravitation mass, often taught as separate properties, are exactly the same. They are both emergent properties of the exact same energy, E/c*c. Energy density curves space-time, creating 'gravity'.
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I am considered a competent Mathematician. I know how to integrate x^2.
1/3 x^3 for the interested student... PLUS a constant C! 😀
Having examined Eli Peter Manor's work:
https://www.scirp.org/journal/paperinformation.aspx?paperid=64066
Reallly, and there is no nice way to say this, it's just junk Science! Even falls Mathematically...
This paper, by a lone Physician, was not published in a serious Physics journal. Alarm bells ring.
A Child of Ten can see that the second (energy) terms cancel under summation. The first term is some sort of Lorentz-Fitzgerald contraction. Leading to absolutely nothing. Or ZERO as we Mathematicians say. 🙂
Better links include Wikipedia and CERN:
https://en.wikipedia.org/wiki/Gravity
https://cerncourier.com/p/magazine/
No, I don't claim to fully understand the Stress-Energy Tensor or 4 Dimensional Polytopes either.
https://en.wikipedia.org/wiki/Regular_4-polytope#Regular_convex_4-polytopes
Just a gut feeling, but the self-dual 24-Cell looks promising. With a Symmetry comes a Conservation Law. Emmy Noether proved that.
1/3 x^3 for the interested student... PLUS a constant C! 😀
Having examined Eli Peter Manor's work:
https://www.scirp.org/journal/paperinformation.aspx?paperid=64066
Reallly, and there is no nice way to say this, it's just junk Science! Even falls Mathematically...
This paper, by a lone Physician, was not published in a serious Physics journal. Alarm bells ring.
A Child of Ten can see that the second (energy) terms cancel under summation. The first term is some sort of Lorentz-Fitzgerald contraction. Leading to absolutely nothing. Or ZERO as we Mathematicians say. 🙂
Better links include Wikipedia and CERN:
https://en.wikipedia.org/wiki/Gravity
https://cerncourier.com/p/magazine/
No, I don't claim to fully understand the Stress-Energy Tensor or 4 Dimensional Polytopes either.
https://en.wikipedia.org/wiki/Regular_4-polytope#Regular_convex_4-polytopes
Just a gut feeling, but the self-dual 24-Cell looks promising. With a Symmetry comes a Conservation Law. Emmy Noether proved that.
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What a superb opportunity for travel. We can hitch a space probe to the next star that wanders close by and let it be carried forth. Every 50,000 years is a long horizon for planning space travel projects but on the length and time scales of our galaxy it's no worse than British Rail.
It's been a long thread, so just a reminder that Eli Peter Manor was the author of the paper Quark Oscillation Causes Gravity that Edbarx introduced in his opening post.
His four scientific contributions can be viewed here: https://www.researchgate.net/scientific-contributions/Eli-Peter-Manor-2073758644
Some explanation of the term "emergent property" may be in order: "An emergent property is one that can only be inferred from an understanding of the properties of its microscopic constituents".
Returning to gravity, there is a controversial theory called emergent gravity that maintains that gravity is not a fundamental interaction, but is a force which is subject to quantum level disorder. Emergent gravity provides an underlying framework to explain Modified Newtonian Dynamics, or MOND. https://en.wikipedia.org/wiki/Entropic_gravity
After 174 posts...did you come up with a solution what exactly generates gravity? Is this thread going to generate 174000 more posts like the other similar ones?Maybe the physics forums should move here...
Look at the Einstein Field Equation which is shown in simplified form below.
The left hand side 'G' like symbol represents how spacetime is warped or curved by matter and energy.
On the right hand side of the equation, the 'T' symbol is the stress-energy tensor.
The stress 'T' on spacetime has to be extremely large to produce an appreciable amount of warp or curvature 'G'.
It takes an object like the Earth (all 6 trillion trillion kilograms of it) to warp spacetime to a level that we're familiar with!
I got the information here: https://blogs.scientificamerican.com/life-unbounded/just-how-resilient-is-spacetime/
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The purpose of this thread is not to come up with a solution, but to examine theories of gravity.
Because we're in The Lounge we are entitled to prattle on about anything connected with gravity, and may do so for some time yet! 😉
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Yes, there maybe better ways to label it than 'emergent property', it's a term I heard used by somebody else and when I first heard it I found that it made immediate sense to me but as you remind me, that doesn't imply others will find it makes immediate sense to them too.
Although it's not perhaps the way in which I would have defined the term emergent property it's close and if I were to use what you have quoted as a starting point I might edit it thus: "An emergent property is one that can only be inferred from an understanding of the behaviour & properties of its constituents" but I'm no English major.
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Thing is, if we start with Einstein's interpretation that gravity is the curvature of space time, and then accept (you may choose not to of course) that this curvature is generated by and in proportion to energy density, we can begin to look for the Cause' of gravity in Energy itself. What is energy ?
energy: "the property of matter and radiation which is manifest as a capacity to perform work", which starts to sound like a circular argument but of course gravity doesn't just 'do work' on objects, it also changes time. Does energy density create time, does time create gravity. I see many circular arguments without any real understand of what's at the bottom, it's turtles all the way down.
energy: "the property of matter and radiation which is manifest as a capacity to perform work", which starts to sound like a circular argument but of course gravity doesn't just 'do work' on objects, it also changes time. Does energy density create time, does time create gravity. I see many circular arguments without any real understand of what's at the bottom, it's turtles all the way down.