Image Credit: Getty, https://www.technologyreview.com/2019/12/14/131574/tidal-forces-carry-the-mathematical-signature-of-gravitational-waves/
Observation is the fundamental pillar of science, it is to find out patterns in nature and construct the resultant into something which makes sense to us. Science without Observation wouldn’t have evolved this far as we see it today, since during historic times there was no sophisticated, state of the art technology available, humans were relied on their senses with “vision” or “seeing” is the most important of them. This is due to the fact that substances, bodies, or phenomena were observed before deriving any further conclusion for the latter with the help of our other senses. So basically to understand a specific thing and to draw resultant conclusions, vision, or observing the thing is the primary objective, which would help us yield its possible outcomes.
Galileo invented the telescope, one of the first observational devices of Astronomy which projected the outer space to Humans in a perceptive way. Witnessing Cosmic phenomena, bodies or even anomalies is easier today since Humans have evolved the technology and came out with new inventions to an extent that scientists are facilitated to detect these above-mentioned things across the Electromagnetic Spectrum (Electromagnetic Spectrum- It is a classification of different kinds of Electromagnetic waves like Radio waves, X-rays, Visible Light, etc. on the basis of their wavelengths Visible Light is the only Electromagnetic wave visible to we humans).
The Need to evolve Observational Astronomical technologies and concepts:
Astronomy and Astrophysics are highly dependent on Observations since it reveals the truest and the purest of colors of the Universe. But everything in the vast Cosmos is not visible as some of the cosmic phenomena, and anomalies do not propagate in the form of Visible Light. Hence Scientists improvised all these years by evolving the technologies for capturing these “cosmic information” released by specific phenomena or anomalies in space. Engineers and Scientists developed telescopes that are able to detect these phenomena throughout the whole Electromagnetic Spectrum be it Radio telescopes, X-ray telescopes, or even Gamma-ray telescopes to name a few. But this isn’t the conclusive point of observational Astronomy since a lot of other anomalies are happening in the Universe which isn’t limited to the Electromagnetic Spectrum, one of these famous cosmic phenomena is Gravitational waves, which may be considered as a milestone for Astronomy and Astrophysics.
What are Gravitational waves?
Image Credit: R. Hurt/Caltech-JPL, https://www.nasa.gov/feature/goddard/2016/nsf-s-ligo-has-detected-gravitational-waves
Gravitational waves also known as Gravity waves are violent and powerful distortions on the fabric of Space-time. These fundamentally are “Ripples” on the surface of Space-time which propagate with the speed of light and have variable magnitude.
Albert Einstein theorized that the Space is not absolute, it actually is a surface which curves due to the effect of Gravity by any substance with mass, and this may be visualized by a simple experiment:
1.) A rubber sheet or cloth is stretched tightly, then a ball is kept on it
2.)The Ball creates a depression/valley/curve on the surface of the desired materials mentioned above
3.) This clearly provides a miniature visualization of how mass and energy curves space-time
Gravity besides its basic meaning is actually the influence on a cosmic object, phenomena, or even light when it passes from or near from depression as explained above by another cosmic object or phenomena which creates that depression. This influence tends to attract it due to the distortion created on space-time fabric.
This is an example that explains what Space-time is according to Einstein’s theory of Relativity (though this is just an example to imagine a 2-D form of Space rather than its 4-D structure). Einstein clearly explains that “Gravity” so commonly referred to as a force is actually a function Space-time itself.
In 1916 Einstein in his theory also predicted there are specific “Ripples” (like the ripples on the surface of the water when an object is dropped into it) which are produced due to some extremely violent cosmic phenomena if at all Space-time is what actually he theorized. Turns out after his predictions were proved to be accurate, there was an existence of this amazing phenomenon which was actually ruled out by Einstein later as it did not make any sense to him.
How are these waves produced?
Image Credit: AURORE SIMONNET/LIGO/CALTECH/MIT/SONOMA STATE
These “Ripples” on the surface of Space-time are resultant of an event like merging Black holes, Binary or pair of rotating Black holes, Binary neutron star systems, and Asymmetric neutron stars, etc. Their energetic revolutions cause Space-time to distort, just like crumpling up a sheet of paper by applying force to it. This may be visualized by putting a hand blender in water, the rotation of the blender blades creates “Ripples” on the surface of the water very similar to Gravitational waves.
Anything in the Universe which is violent and has some influence of very high mass substances or energies are bound to distort the Space-time fabric hence causing Gravitational waves for example- Supernova explosion.
Even during the origin of our Universe “the Big Bang” considered as the most violent cosmic phenomena whose resultant is this ever-expanding Universe formed in which we live, the after-effects just milliseconds after Space-time came into existence might have produced extremely powerful Gravitational waves with an unimaginable magnitude.
These specific waves 12 to 13 billion years ago if detected by scientists would provide an introduction to our Universe’s existence just after the “Big bang”. The problem being the magnitude might not be sufficient enough to detect them and probably it might take more time and more advanced technology to successfully detect these, who knows the results are uncertain.
Characteristics of the Gravity waves:
These waves though may be visualized by us by conducting a simple experiment (as discussed above) but are not visible. These waves affect the fabric of Space-time itself:
1.) Consider taking two coordinates in Space
2.) Gravity wave basically will expand and contract the distance between these two points
This distortion will be dependent on the magnitude of the wave, the stronger the wave the more distortion is experienced on the fabric of Space-time.
Gravity waves travel at the speed of light but still detection of these waves is extremely complicated and difficult. This is due to the fact that we do not have any Binary system of Black holes, neutron stars, or supernovae near us, the distance from these phenomena is huge ranging from millions and billions of light-years. The problems are (1) Time is taken and (2) Enormous distances due to which these waves lose their magnitudes making detections even more difficult. Considering our distances from the violent sources that cause Gravitational waves, the wavelength which we might come across for detection would be something like detecting a protons vibration in short unimaginably short wavelengths.
Electromagnetic Radiation may get absorbed, reflected, or refracted due to its high interactions with matter present in the Universe, Gravity waves travel inter-galactic space free of distortions or alterations providing a much clear picture of the Universe which also helps to study cosmic anomalies of Astrophysical importance like never before.
Science is evolving and developing at a fast pace which is also giving humanity opportunities that did not exist earlier. These opportunities will bring us closer to nature and will help us understand our place in the Universe and answer the question that- what is the fundamental reason for our existence?
References:
1.) Laser Interferometer Gravitational-wave Observatory (LIGO), https://www.ligo.caltech.edu/page/why-detect-gw
2.) Laser Interferometer Gravitational-wave Observatory (LIGO), https://www.ligo.caltech.edu/page/what-are-gw
3.) Laser Interferometer Gravitational-wave Observatory (LIGO), https://www.ligo.caltech.edu/page/ligo-gw-interferometer
4.) Massachusettes Institute of Technology, Technology Review, (MIT), https://www.technologyreview.com/2019/12/14/131574/tidal-forces-carry-the-mathematical-signature-of-gravitational-waves/