Scientists the University of West Scotland have recently confirmed the existence of a pear shaped nucleus in Barium-144. How does this relate to time travel? To understand that we’ll have to back up a bit.
The universe is governed by laws of symmetry. For now we will focus on two kinds: P symmetry (parity) and C symmetry (charge).
In simple terms, parity transformation means that if there is a coordinate that exists at position (x, y, z), there is also a coordinate that exists at (-x, -y, -z). Some quantities will change through inversion of the origin. For example, you can have velocity of 5 mph or -5 mph, force of .3 N or -.3 N, etc. Conversely, some quantities are not changed by spatial inversion. Time, mass, energy, magnetization, and more are independent of location. This makes sense, as moving your cellphone a few inches to the right does not affect its mass or magnetization, nor does it change time.
C symmetry basically means that a positively charged particle will behave the same way as a negatively charged particle, though the sign may be different. A wire with 4 mC of positive charge will behave the same as a wire with 4 mC of negative charge, though the signs of the interactions may be opposite.
This works fine at describing the nuclei of atoms because they were generally understood to be spherical, disk, or football shaped.
However, with the discovery of a pear-shaped nucleus it becomes more difficult. To understand that, look at an actual pear. The bulging part has more fruit than the narrower part. In the same way, a pear-shaped nucleus has more protons at its bulge than in other areas, making the distribution asymmetric, with areas of more positive charge than negative charge.
Our universe is made up of anti-matter and matter. When the two combine they convert into radiation. If the universe had equal amounts of both, nothing would exist except for radiation as a result of their interaction. The only problem is that things do exist. A lot of things, actually. Everything in the universe that exists, exists. Scientists have not agreed to an explanation as to why more matter seems to be present than antimatter, but this nucleus could be the key to learning why.
When we construct our universe upon symmetry, the lack of antimatter would seem to violate our rules. However, a pear-shaped nucleus now proves that things exist asymmetrically and can lead to further research to determine why.
So where does time travel come in? To find the answer you have to look at the where the “tail” end of the pear is pointing. Dr. Scheck, the leader of the initial project, states that they “literally ‘point’ towards a direction in space. This relates to a direction in time, proving there’s a well-defined direction in time and we will always travel from past to present.”
To understand this, imagine you were in the Oval Office of the White House and pointed to President Obama sitting at his desk. You would be gesturing to a specific point in space, but also to a specific point in time. If you had pointed to that spot (relative to the earth) fifty years ago, you would be pointing to President Johnson. This is an oversimplification, but it helps to show how space and time are intrinsically related. Because the earth, solar system, sun, galaxy, etc. are all constantly moving, to refer to something in a position in space, you must also refer to the time at which it existed there. Hence, we call it space-time.
If everything is completely symmetric, then in theory time should be able to run forward or backward as simple as changing the sign in an equation, but it doesn’t. The Second Law of Thermodynamics states that the universe decays toward entropy; simply, it’s always easier to a make a mess than to clean it up, and the universe will continue to make more messes. The last form of symmetry, T symmetry, is not adhered to by the observable universe. The asymmetry of time could be evident in the pear shaped nucleus as Redditor Eain points out:
Nothing exists in three dimensions.
To compare and simplify, consider only the 3 known spatial dimensions: paper isn't 2 dimensional. It's incredibly small in one dimension, but it still exists in all 3. Everything in the known universe is this way; even subatomic particles exist in all 3.
Similarly, nothing actually exists in only those 3 spatial dimensions. To say "How can you point forward in time on a 3 dimensional plane?" Doesn't apply here, because things don't exist on a 3 planes; they exist on at least 4.
To further clarify, I'll use another example; look at this image. (Ignore the text)
https://adamsart.files.wordpress.com/2008/07/egg-pics_1_1.jpg
The eggs in this picture are all 2D projections of a 3D object. And all of them are eggs, and thus egg-shaped, in 3D. But notice the egg on the left; it looks round, not oblong. Why is that? Because the oblong shape extends in the dimension we can't see; we're not looking at the whole object, so we missed part of it.
Similarly, objects extend in all dimensions, not just the 3. This study shows that atoms are sometimes egg-shaped, not round; what if all of them are? Now reffer back to the picture; if in 3 dimensions, it looks like it's round, but we know that it's egg-shaped, then the oblong must extend into another dimension. The researcher posited the conjecture that the dimension in which things are oblong is time. This would mean they exist farther into the future than the past (the past being the short fat end, the future being the longer tip).
It's a leap, and it doesn't even quite fit the nature of time as a dimension (by the standard interpretation) but it's possible I suppose.
This discovery could help us understand why the universe moves in one direction in time when everything else moves independently.
So because this pear seems to point at a something in space-time, we can’t time travel? Well, maybe. That is the conjecture on part of the research team who conducted the study, but the science stops there. Up until now we’ve not had success in the time travel department, and still cannot definitively comment on its possibility. Though some say this disproves the ability for time travel, and while it very well may, the research is still young. Even if it means we have to rewrite the textbooks and change our understanding of the universe, all of his contributes to a better understanding of the world around us. If time travel is a possibility, having a more accurate description of our universe would only bring us closer to it.