Friday, 26 July 2013

A particularly bad headline

From Gizmodo: Scientists Just Discovered a New Force That's Stronger Than Gravity

Okay, so many things wrong with this headline. To start with, gravity is the weakest of the four fundamental forces, so "stronger than gravity" applies to just about everything. But that's not the biggest problem here. The headline, by pairing "new force" with "gravity", seems to suggest that someone has discovered a new fundamental force. This isn't what happened.

Quick overview: there are four fundamental forces. In order of strength they are: Gravity, Electromagnetism, Weak Nuclear Force, Strong Nuclear Force. Gravity is weak, but because it only ever adds (nothing has "negative" mass), it ends up being powerful on large scales, like planets and stars. The Weak Nuclear Force is a little obscure, but as the name suggests is involved in nuclear processes like atomic decay. The Strong Nuclear Force is what holds nuclei together, and it's what makes nuclear weapons so powerful.

Everything else is electromagnetism. Friction, contact forces, air pressure, water pressure, everything other than gravity that you experience can ultimately be traced back to electromagnetism in its various forms.

The "New Force" in this article is electromagnetism. The researchers looked at the effect of blackbody radiation (which is a type of electromagnetic radiation) on hydrogen atoms in an astrophysical context. (Here's the article; it's behind a paywall though.) They found that it could create an attractive force between the atoms which hadn't been appreciated before. But keep in mind that what they have found is a new way in which the electromagnetic force is expressed, not a "New Force" in the fundamental force sense.

Onto the "Stronger Than Gravity" part. The researchers noted that this blackbody force they discovered could be more important than gravity in the context of star formation. In a nebula, there's a lot of hydrogen, but it's really spread out--it's waaay less dense than air. (Star Trek has led many people astray by depicting nebulae as clouds that ships can hide in. Look at a picture of a nebula. In most of them you can see stars through them, even though they're light-years across. Anything with visibility measured in trillions of kilometres is a bad hiding place.) Somehow, over time the hydrogen in a nebula manages to coalesce into a star, with an enormous density. Exactly how this happens is a subject of ongoing research, and this new blackbody force could play an important role in that. Because at the densities the nebula starts at, the gravitational forces involved are super, super, super small. So even thought this blackbody force is super, super small, it could still be important.

It is not, though, "Stronger Than Gravity" in an every-day sense. You will not be levitated by blackbody forces. They will not explain dark matter or the expansion of the universe.

It's starting to sound like I might be down on this research, but I'm really not. It's a novel idea that is important to an area of ongoing research in astrophysics. That's basically the goal when you write a journal article. The headline writers at Gizmodo simply did a horrible job summarizing it. Good research deserves a better headline than this.

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