5 June 2022
The concept of a mirror universe is a standard trope in science fiction. A world much like ours the place we would discover our evil doppelganger or a model of us who really requested out our highschool crush. However the idea of a mirror universe has been usually studied in theoretical cosmology, and as a brand new research exhibits, it would assist us remedy issues with the cosmological fixed.
The Hubble fixed, or Hubble parameter, is a measure of the speed at which our universe expands. This enlargement was first demonstrated by Edwin Hubble, utilizing knowledge from Henrietta Leavitt, Vesto Slipher, and others. Over the following a number of a long time, measurements of this enlargement settled on a fee of about 70 km/sec/Mpc. Give or take fairly a bit. Astronomers figured that as our measurements turned exact, the varied strategies would decide on a standard worth, however that didn’t occur. The truth is, prior to now a number of years measurements have develop into so exact they outright disagree. That is typically referred to as the cosmic pressure downside.
At this level the noticed values of the Hubble fixed cluster into two teams. Measurements of fluctuations within the cosmic microwave background level towards a decrease worth, round 67 km/sec/Mpc, whereas observations of objects comparable to distant supernovae yield a better worth round 73 km/sec/Mpc. One thing clearly doesn’t add up, and theoretical physicists try to determine why. That is the place the mirror universe would possibly are available in.
Wild concepts are likely to fall out and in of recognition in theoretical physics. The mirror universe concept is not any exception. It was studied fairly a bit again within the Nineteen Nineties as a approach to take care of the issue of matter-antimatter symmetry. We are able to create matter particles within the lab, however after we do, we additionally create antimatter particles. They at all times are available in pairs. So when particles shaped within the early universe, the place did all their antimatter siblings go? One concept was that the universe itself shaped as a pair. Our matter universe and an analogous antimatter universe. Downside solved. The concept fell out of favor for varied causes, however this new research appears at the way it would possibly remedy the Hubble downside.
The group found an invariance in what are referred to as unitless parameters. Probably the most well-known of those is the tremendous construction fixed, which has a worth of about 1/137. Mainly, you’ll be able to mix measured parameters in such a means that each one the items cancel out, giving you an identical quantity it doesn’t matter what items you utilize, which is nice in case you are a theoretician. The group discovered that whenever you tweak cosmological fashions to match the noticed enlargement charges, a number of unitless parameters keep the identical, which suggests an underlying cosmic symmetry. For those who impose this symmetry extra broadly, you’ll be able to scale the speed of gravitational free-fall and the photon-electron scattering fee in order that the totally different strategies of Hubble measurement higher agree. And if this invariance is actual, it implies the existence of a mirror universe. One that might have an effect on our universe by a faint gravitational pull.
It ought to be identified that this research is usually a proof of idea. It lays out how this cosmic invariance would possibly remedy the Hubble fixed downside, however doesn’t go as far as to show it’s an answer. A extra detailed mannequin shall be wanted for that. Nevertheless it’s an attention-grabbing concept. And it’s good to know that in case your evil doppelganger is on the market, they will solely affect your life gravitationally…