Paul M. Sutter is an astrophysicist at The Ohio State University, host of Ask a Spaceman and “Space Radio,” and creator of “Your Place in the Universe.” Sutter contributed this text to Space.com’s Expert Voices: Op-Ed & Insights.
The true nature of dark energy continues to evade our understanding, regardless of 20 years of investigation. Frustratingly, most makes an attempt to clarify dark energy fail extraordinarily stringent exams of particle physics.
But new analysis exhibits how a hypothetical type of dark energy is likely to be made inside the sun and could possibly be detected right here on Earth. In truth, we might have already seen it.
A secret within the dark
In 1997, astronomers shocked themselves and the world with the invention that the expansion of the universe is accelerating. They gave this accelerated enlargement a cool title — dark energy — as a result of they didn’t perceive what should be blamed for this unusual cosmological impact.
The easiest clarification for dark energy is that it is a “cosmological constant,” an additional quantity tossed into Einstein’s theory of general relativity. In different phrases, on this view, the enlargement of the universe accelerates as a result of … the enlargement of the universe accelerates — which is not precisely a satisfying clarification. Physicists have tried to attach this cosmological fixed to the quantum vacuum energy discovered all through space-time, however their calculations estimate a power for the accelerated enlargement about 120 orders of magnitude too huge.
So maybe dark energy is not embedded instantly in space-time itself. Maybe there’s some new power, subject or particle at work within the universe — one thing beforehand unknown to the Standard Model of particle physics. This entity would clarify the accelerated enlargement, however theoretical fashions run into points right here, too.
The downside is that when you introduce a brand new power, subject or particle into the combo of the elements of the cosmos, that power, subject or particle will begin interacting with all the different forces, fields and particles recognized to physics. And as a result of we don’t have any hints of any new physics in any of our high-energy (not to mention low-energy) physics experiments, that does not look like a viable choice.
Behind the display
Maybe dark energy has yet another trick up its sleeve. Maybe there’s some entity that generates the accelerated enlargement at giant cosmological scales, and one thing inside that entity screens it from interacting with recognized physics at small solar system scales.
It’s a little bit of a stretch, however since we don’t know what’s creating dark energy, it is price investigating. But how do we discover one thing in our experiments that is designed to be hidden from our experiments?
Some theorists have proposed that dark energy is likely to be brought on by some new form of particle. This hypothetical particle would not be capable of work together with different particles from the Standard Model (like electrons and high quarks), as a result of it could have been produced in nice amount within the middle of the solar, the place the densities and temperatures are excessive sufficient for interactions between dark energy and the Standard Model to happen. The manufacturing of dark energy particles contained in the solar would mess up its thermal equilibrium, altering its gentle output, temperature and lifespan. And as a result of the solar’s conduct traces up with precisely what we anticipate from the Standard Model, it could actually’t be producing dark energy particles in its core, based on these theories.
But a latest paper posted to the preprint database arXiv.org proposes one other chance: Perhaps dark energy would not join on to any Standard Model particles however does hook up with photons.
Deep contained in the solar, there’s a area referred to as the tachocline, the place the solar’s magnetic subject is extraordinarily sturdy. Magnetic fields are carried by photons, so tons of photons are produced within the tachocline. If dark energy one way or the other connects to photons, then that is the place dark energy particles is likely to be produced, too.
Now you see it
The upshot is that there would possibly certainly be a way for the solar to spit out dark energy particles. These dark energy particles would then shoot via the rest of the solar’s bulk, via empty space, and stream via you proper now.
There’s one other entity within the universe that is likely to be silently streaming via you proper now: dark matter. Dark matter is the invisible type of matter that makes up over 80% of the mass of the universe. Like this hypothetical type of dark energy, dark matter is probably going product of a particle at the moment unknown to the Standard Model of particle physics and streams via the universe. And it, too, is totally mysterious.
Several experiments scattered throughout the Earth are attempting to find elusive dark matter particles, as scientists hope to catch a glimpse of an especially uncommon interplay. Recently, a kind of experiments, XENON1T, witnessed a sign that it could not absolutely clarify — the primary slight trace of such a detection.
And there’s an opportunity, based mostly on the newest analysis, that what the experiment detected might not have been dark matter, however dark energy. It’s not a really sturdy detection, and it is from a affirmation of the character of dark energy. But a touch is a touch. It’s been over 20 years for the reason that authentic discovery of dark energy, and principle and experiment alike have didn’t make a lot headway.
Scientists hope that future dark matter detection experiments, like XENONnT and PandaX-4T, will present extra knowledge and at last give us our first glimpse of the dark universe.
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