Scientists have made the first direct observations of gravitational waves, which are ripples in the fabric of space-time predicted by Albert Einstein. It is similar to ripples caused by a rock thrown in a pond, but the difference is that these may go on forever through the space-time fabric. The hero is LIGO, which is an acronym for Laser Inteferometer Gravitational-wave Observatory. LIGO picked up gravitational waves created by two merging black holes, which occurred about 1.3 million years ago. Yet, we can still hear them, rippling through the fabric.
Wow! So, what does all this mean? Well, it may herald a future in astronomy where we can finally learn more about the dark side of our universe. LIGO may pick up gravitational waves caused by both dark matter and dark energy. Perhaps we will detect waves from the Big Bang. Only time will tell, but at a minimum astronomers will be able to study other black holes.
LIGO was designed to search for compact binary objects such as pairs of neutron stars or black holes, locked into the spiraling dance of death. In 1993, Joseph Taylor and Russell Hulse won the Nobel Prize in physics after showing that binary neutron stars radiated gravitational energy. This was the precursor or indirect proof of gravitational waves.
Patrick Brady, a professor at the University of Wisconsin who worked on LIGO explained the project: “LIGO senses those last few minutes or seconds of the waves generated just before the objects crash into one another.” He said that LIGO begins to hear the impending collision once the orbits tighten to about five times per second. At that point, the gravitational waves reach a frequency of 10 hertz, or cycles per second, the low end of its range. And in the few minutes left in their lives, the tightening spiral causes both the frequency and strength of the gravitational waves to increase. Brady concluded, “That means they sweep right through the most sensitive band of the LIGO instruments.”
Scientists are in the early stages of developing supermassive LIGOs to find supermassive black holes in the center of galaxies. Just like light giving off different frequencies, the gravitational waves also give us different frequencies. Thus, we will need to develop supersensitive instruments that can detect unique chirps in a field of crickets. Currently, there are only two detectors online (LIGO and Virgo, the European Gravitational Observatory’s primary instrument in Italy), but researchers will create more and improve them incrementally. They will broaden the range of detectable waves and pinpoint sources of waves. Italy’s Advanced Virgo instrument will come online in the fall of 2016. Others will follow.
In December, the European Space Agency launched the Laser Interferometer Space Antenna (LISA) Pathfinder into orbit 932,000 miles from Earth. Even though, Pathfinder will not be searching for gravitational waves, it will prove that a hypersensitive, space-based wave detector is possible to launch into space. Space will be able to filter out the static and noise detected with earth-based instruments. Martin Hewisson, LISA Pathfinder scientists said, “We want to make this the quietest place in the solar system. If LISA is successful, scientists can build a gravitational wave detector called eLISA, which will consist of three spacecraft in an equilateral triangle connected by laser arms. This detector will pick up gravitational waves generated by binary supermassive black holes, ultra-compact binaries, and small black holes falling into supermassive black holes.
Different events produce gravitational waves of different frequencies. The above graph compares those sources against operating and future detectors. This shows the potential for future astronomers being able to detect not only where black holes are located in our universe, but perhaps even locating the Big Bang.
But even before we have eLISA, new ground-based gravitational wave detectors should turn on within a few years. These new instruments will allow astrophysicists to triangulate the positions of waves and hone in on their sources. An upgraded version of Virgo will begin observations in the fall of 2016 in conjunction with LIGO. Advanced Virgo’s improvements will increase its sensitivity ten times. This will allow researchers to probe a volume of space thousands of times larger than before. Virgo could pick up a gravitational wave signal once per month, or even per week, with its enhancements. LIGO India is a proposed detector that would serve as the third in the LIGO family and could be operational by 2022. In Japan, crews have blasted and excavated tunnels in the abandoned Kamioka mine to make way for the Kamioka Gravitational Wave Detector (KAGRA). KAGRA is expected to detect signals from neutron star mergers every one or two months once it is fully operational.
The Einstein Telescope represents a third-generation detector that is in the design phase. It would be hundreds of times more sensitive than the instruments we have now. This telescope will be buried underground to reduce noise. It will form a full triangle like eLISA and will have three detectors: two for low-frequency signals and one to detect high frequencies.
A new era in astronomy is set to begin based on a heightened sense of listening. So, what is the gravity of this new discovery? Well, certainly it gives us a new tool for detecting dark matter through sound, which otherwise cannot be detected with sight. But more importantly, it gives us a basis for using our imagination to carry beyond the simplistic theory of the Big Bang and expansion until everything freezes in the icy depths of space. Now, we know that Einstein got it exactly right and that the space-time fabric carries throughout the universe. This fabric is so connected that gravitational waves created over a billion years ago still vibrate across the fabric.
What does all this mean? Well, I’m not certain, but I think it means that everything in our universe, including time and the Big Bang are still in this fabric. That may mean that past, present, and future are just nouns that help us imagine where we are in that fabric. And whether this fabric encloses on itself so that time is continuous or whether this fabric is part of a perpetual time machine that expands and contracts, it really does not matter. Because the primary point is that the universe is all interconnected in one fabric. Solar systems are connected to galaxies and galaxies are connected together, so that our universe is one entity. We don’t know if there are other universes which are also connected like cells in an organism, but we know that we are connected in our universe.
This helps explain a lot of mysteries in our universe. Now, we know why the stars orbiting on the outside of the Milky Way galaxy are traveling at the same speed as the stars on the interior. They are all connected in the space-time fabric. Typically, you would expect the exterior stars in a galaxy to slow down as they get farther away from the center, which probably houses a supermassive black hole. But if they are in the same fabric as those stars located closer to the center, the distance from the supermassive black hole will not change their speeds.
What else? Well, this may explain why we can see the galaxy EGS8p7, located 13.2 billion light years away from earth. This galaxy, the farthest we have seen as of today, was formed about 600 million years after the Big Bang. So since this ancient galaxy no longer exists, how can we still see the light that traveled 13.2 billion years to reach us? Traveling at the speed of light, which is faster than any speed our earth can obtain, the light from EGS8p7 would have zipped past us billions of years ago, never to be seen again. However, if you analyze EGS8p7 as being forever locked into the space-time fabric, then we may someday even discover the Big Bang, also embedded in the same fabric. And the mystery about why we can still see or hear evidence of ancient galaxies is solved by the space-time fabric, which embraces everything that ever happened or ever will happen in our universe. However, it makes for a strong case that we currently are in a contraction phase since we can see ancient galaxies just as if we were moving back in time.
Now we can start examining our universe as if it were one entity so that if we detect contraction where we are, the entire fabric of the universe is contracting. And our universe must be closed by virtue of the fact that a fabric has an end. The only questions remaining are: (1) is our universe enclosed in a huge orbit and (2) does it both expand and contract?
It seems highly likely that our universe is enclosed in some type of geometrical figure. If a system is closed, it must have edges. And if it has edges, these edges must form some type of design that connects. The second question is the tougher one. Scientists believe that the universe has been expanding since the Big Bang and many cosmologists think that it will end in a Deep Freeze. This theory seems ridiculous to me.
Our universe is most likely designed to last forever in a perpetual motion mechanism. The red shift discovered by Edwin Hubble supports the theory of expansion. However, the red shift may also support the theory of contraction. For example if dark energy were to cause expansion and dark matter were to cause contraction of our visible universe, the galaxies would appear to be pulling away from each other in either case. In other words, the dark energy would propel galaxies away from each other, while the dark matter would cause galaxies to contract, shrinking uniformly. Both expansion in distance and shrinking in size will cause a red shift.
If there were an original expansion of the fabric, then there should also be a contraction if you believe that our universe is a perpetual time machine. This makes sense to me because if the past and future are in the same fabric, then going backwards in time is not only possible, but is likely. From our perspective, we may go back to the Big Bang, but we may call it the Big Crunch.