Ever since Isaac Newton first published his general universal law of gravitation, in 1687, the race to find the explanation of this mysterious force has been on. Countless generations of physicists have tried to answer a simple question, namely how is gravity transmitted with so much accuracy and almost instantly over empty space. Once Einstein revealed his general theory of relativity, this query was partially answered, but soon it became obvious that Newton's ideas needed some “tweaking.”
That is to say, Einstein claimed that objects such as planets, solar systems and galaxies exhibited the trait of gravity simply because objects that had mass or energy tended to wrap time and space around themselves, thus causing other similar objects to fall towards them.
The higher the energy or the mass, the higher the force of gravity. However, new quantum theories hold that all the four universal forces, gravity, electromagnetism and the strong/weak nuclear forces interact with each other by constantly exchanging particles.
Under quantum theories, gravity manifests itself through a theoretical particle, known as graviton. But the problem is that relative physics does not allow for such a particle to exist, hence the current dilemma in this field. Scientists now have to simply look for a larger “framework,” one that would help incorporate all the theories (Newton's, Einstein's and those of quantum physics), into the larger “theory of everything.”
By observing the way in which the Universe acts and expands, astrophysicists have hypothesized that dark energy might be one explanation for the way in which gravity acts in the vastness of space. For instance, they say, photons from the cosmic background radiation travel the entire length of the known Universe, passing through numerous galaxies on their way. But, as they do so, their path accelerates as they enter these formations, and then slows down upon exit.
However, over the past millions of years, scientists believe, the speed at which the Universe is expanding has increased significantly, mainly because these photons have started retaining their exit speed, after going out of the galaxies they pass through. One possible explanation is that dark energy is acting like some sort of repellent gravity. Following this line of thought, photons should exit galaxies super-hot, and they do. The problem is that they do so twice as hot as they should if dark energy was acting alone.
At this point, finding a unified theory is simply guesswork, as direct observation on dark energy and dark matter is physically impossible. All that remains is for theoreticians to give it their best shot, and for technology to evolve to a point where such observations would become possible.
Find us on Google+
