RECENT ARTICLES

Resolving the black hole firewall paradox—by calculating what a real astronaut would compute at the black hole's edge.

Defining a ‘quantum clock’ and a 'quantum ruler' could help those attempting to unify physics—and solve the mystery of vanishing time.

Calculating the odds that intelligent observers arise in parallel universes—and working out what they might see.

A bench-top experiment could test the notion that gravity breaks delicate quantum superpositions.

Accounting for quantum fuzziness could help us measure space and time—and the cosmos—more accurately.

FQXI ARTICLE

February 22, 2018

The Myth of Gravity

A new model in which gravity is not a fundamental force could—counterintuitively—give a controversial quantum gravity theory a boost. It may also change our picture of spacetime, and do away with dark energy.

April 24, 2010

Erik Verlinde

University of Amsterdam

Gravity may be the force that we are most familiar with in everyday life, but physicists do not yet understand its origin. Newton told us that apples fall towards Earth with an acceleration that depends on the Earth’s mass, the apple’s mass, and its distance from the centre of the Earth, while Einstein described gravity by the warping of the fabric of spacetime. But while these theories describe how gravity works, they don’t explain how it arises.

Verlinde, a string theorist at the University of Amsterdam in the Netherlands, believes that the key to understanding gravity is "information." He was inspired by early work on information storage in black holes by Stephen Hawking and Nobel laureate Gerard ’t Hooft. "When I was about fifteen I saw them on television talking about the physics of elementary particles and black holes," says Verlinde. "I knew then that I wanted to work in that area."

The Television Event Horizon

Hawking and ’t Hooft had both worked on the so-called

Entropic force?

Imagining a particle near a spherical holographic screen

allows you to derive Newton’s law of gravity.

It might sound like re-inventing the wheel, but the approach implies that gravity is nothing more than the result of a system maximising its entropy, or disorder. At first glance, this looks like bad news for the quantum gravity crowd. If gravity is an "entropic force," there is no longer a need for physicists to attempt to reconcile general relativity with quantum mechanics, or hunt for the hypothetical

Quantum Threads

However, not all gravity researchers take that view. Smolin, a long term proponent of loop quantum gravity (LQG), believes that Verlinde’s work is not only compatible with LQG, it could even help to explain how familiar Newtonian gravity might emerge in this picture. According to LQG, spacetime isn’t the smooth fabric that Einstein envisioned; rather, if you zoom down to scales of 10

Smolin notes that Verlinde’s model is tied to earlier work by FQXi member Ted Jacobson, who had shown in 1995 that Einstein’s equations of general relativity could be derived using thermodynamics and the holographic principle. "The wonderful thing about the arguments of Jacobson and Verlinde is they give a deep reason for why a quantum theory of gravity should yield the phenomena of gravitation," Smolin writes in his recent paper (arXiv:1001.3668v2).

There isn’t a fundamental

gravitational interaction.

Is that crazy enough?

gravitational interaction.

Is that crazy enough?

- Paul Frampton

If such derivations of dark energy stand up then Verlinde’s ideas "could in some sense complete general relativity," says physicist Sabine Hossenfelder at the Nordic Institute of Theoretical Physics in Sweden. However, there is still a long way to go before physicists will abandon the notion that gravity is a real force as there are several things that remain vague in Verlinde’s formulation, she adds.

Frampton, however, is convinced that Verlinde is on the right track. "I believe that gravity is entirely explained by increases in entropy; there isn’t a fundamental gravitational interaction," he says. "That’s the bottom line. Is that crazy enough?"

Comment on this Article

Please read the important Introduction that governs your participation in this community. Inappropriate language will not be tolerated and posts containing such language will be deleted. Otherwise, this is a free speech Forum and all are welcome!

function ValidatePostText_main () {
form = document.addPostForm_main;
var recaptcha = $("#g-recaptcha-response").val();
if (recaptcha === "") {
event.preventDefault();
alert("The reCaptcha Box below must be checked before you submit the form");
}
else if (form.postText_main.value == '') {
alert ("The post contains no text");
return false;
}
else {
return true;
}
}

**Your name:**
(optional)

Recent Comments

read all article comments

Please read the important Introduction that governs your participation in this community. Inappropriate language will not be tolerated and posts containing such language will be deleted. Otherwise, this is a free speech Forum and all are welcome!

Please enter the text of your post, then click the "Submit New Post" button below. You may also optionally add file attachments below before submitting your edits.

HTML tags are not permitted in posts, and will automatically be stripped out. Links to other web sites are permitted. For instructions on how to add links, please read the link help page.

You may use superscript (10

^{100}) and subscript (A_{2}) using [sup]...[/sup] and [sub]...[/sub] tags.You may use bold (

**important**) and italics (*emphasize*) using [b]...[/b] and [i]...[/i] tags.You may also include LateX equations into your post.

Insert LaTeX Equation
[hide]

LaTeX equations may be displayed in FQXi Forum posts by including them within [equation]...[/equation] tags. You may type your equation directly into your post, or use the LaTeX Equation Preview feature below to see how your equation will render (this is recommended).

For more help on LaTeX, please see the LaTeX Project Home Page.

LaTeX Equation Preview

preview equation

clear equation

insert equation into post at cursor

LaTeX equations may be displayed in FQXi Forum posts by including them within [equation]...[/equation] tags. You may type your equation directly into your post, or use the LaTeX Equation Preview feature below to see how your equation will render (this is recommended).

For more help on LaTeX, please see the LaTeX Project Home Page.

LaTeX Equation Preview

preview equation

clear equation

insert equation into post at cursor

Attachments
[hide]

You may optionally attach up to two documents to your post. To add an attachment, use the following feature to browse your computer and select the file to attach. The maximum file size for attachments is 1MB.

Once you're done adding file attachments, click the "Submit New Post" button to add your post.

You may optionally attach up to two documents to your post. To add an attachment, use the following feature to browse your computer and select the file to attach. The maximum file size for attachments is 1MB.

Once you're done adding file attachments, click the "Submit New Post" button to add your post.

ANONYMOUS wrote on June 1, 2016

How does the objects interact? What decides whether to attract or repel each other?

How does the objects interact? What decides whether to attract or repel each other?

ANONYMOUS wrote on April 21, 2016

Does this mean that if a large hollow body was placed in space it's"gravity" for lack of understanding, could be equal to that of say..... Earth? Random virtual particles pressing onto the surface from all regions of space? "Gravity" being equal on the inside of the sphere to"gravity" on the outside perhaps? I'm struggling with practical application of this theory, though tantalizing to the imagination.

Does this mean that if a large hollow body was placed in space it's"gravity" for lack of understanding, could be equal to that of say..... Earth? Random virtual particles pressing onto the surface from all regions of space? "Gravity" being equal on the inside of the sphere to"gravity" on the outside perhaps? I'm struggling with practical application of this theory, though tantalizing to the imagination.

STEVE DUFOURNY wrote on March 28, 2016

Hello,

I reread the article about the works of Verlinde.It is very relevant.There is a bridge between our thermo and our gravitation.It seems essential to insert a new quantum of gravitational energy.We have problems if we consider our relativitic thermo.

I am asking me how can we consider the quantum gravitation? The QFT needs a kind of bridge to explain this gravitation which are not a thermodynamical force in fact.Perhaps that we must analyse at zero absolute at 10^-35m .A kind...

Hello,

I reread the article about the works of Verlinde.It is very relevant.There is a bridge between our thermo and our gravitation.It seems essential to insert a new quantum of gravitational energy.We have problems if we consider our relativitic thermo.

I am asking me how can we consider the quantum gravitation? The QFT needs a kind of bridge to explain this gravitation which are not a thermodynamical force in fact.Perhaps that we must analyse at zero absolute at 10^-35m .A kind...

read all article comments