There is considerable speculation as to why the observable universe is apparently composed almost entirely of matter (as opposed to a mixture of matter and antimatter), whether there exist other places that are almost entirely composed of antimatter instead, and what sorts of technology might be possible if antimatter could be harnessed.
Matter and anti matter
At this time, the apparent asymmetry of matter and antimatter in the visible universe is one of the greatest unsolved problems in physics. The process by which this asymmetry between particles and antiparticles developed is called baryogenes.
Whisps and jets of matter and anti matter
In particle physics, antimatter is the extension of the concept of the antiparticle to matter, where antimatter is composed of antiparticles in the same way that normal matter is composed of particles. An antiproton can form an antihydrogen atom in the same way that an electron and a proton form a "normal matter" hydrogen atom.
Furthermore, mixing matter and antimatter can lead to the annihilation of both, in the same way that mixing antiparticles and particles does, thus giving rise to high-energy photons (gamma rays) or other particle–antiparticle pairs. The result of antimatter meeting matter is an explosion.
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Come ride my rocket just you alone, and travel to Mars or places unknown
The Universe was born as a spherical shape.. i.e. expansion occurred in all directions. Spherical and hyper-spherical.
Time as well as space was born, again .. as a function of expansion. Again a spherical shape but as a function of radius.
We can envisage the universe as an expanding balloon where the radius is a measure of time. As the radius grows time also grows.
Let's just take the simple step of assigning time to the radius. So, time (positive) is a direction - the radius. But the universe expanding is spherical therefore any radius direction has an opposite radius direction.
Consider: although both radii are positive to an item located somewhere, each such item has a time running .. IN AN OPPOSITE direction that is the opposite radii on the other side of the spherical expansion.
Antimatter is time reversed matter (fact). So in any Particular place time runs positive BUT as measured from 'the other side of the sphere' the time appears to run in reverse - antimatter.
So there's the answer. The other side of the universe is time reversed in direction therefore mass is antimatter (if we could observe it). However, if you could travel there it would be simply matter.. normal.
There is simply a geometric equivalence antimatter/matter.
However, as we know it is possible for antimatter to exist locally for a smigin. It may well be then that there would appear to be a slight imbalance. Bear in mind though that this is only apparent as the same would be true for 'the other side'.