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How is the speed of light calculated?

How is the speed of light calculated-abhiexo

Undoubtedly, one of the most significant ideas in physics is the speed of light. The time it takes for light to move between two sites is typically used to calculate the speed of light. The speed of light varies depending on the substance it is traveling through, and it is represented by the letter C and is equal to 299,792,458 meters per second.

Ole Roemer (1644–1710), a Danish astronomer, was the first to calculate the speed of light in 1676. By monitoring eclipses of Jupiter’s moon, Roemer calculated the speed of light. He became fascinated on some odd movements of the moon Io orbiting Jupiter. Moon lo (Jupiter’s fifth moon) is the solar system's most active volcanic body. Numerous volcanoes, some of which are hundreds of miles high, are scattered across Io's surface. The big planet occasionally covered its small moon from our view, resulting in an eclipse, although the intervals between eclipses appeared to shift over the year.

Following several years of observations, Romer found the connection. We’re in a specific spot in our own orbit around the sun when we witness the eclipse of Io. But a few days later, when another eclipse occurs, we’re in a slightly different spot. We might be nearer or farther from Jupiter than we were before. The next eclipse will have to wait a little bit longer if we are farther away than when we last witnessed one. If light has a fixed speed, then this is the only way to account for the differences in the timing of Io eclipses. The diameter of the Earth's orbit, according to Roemer, may be traversed by light in twenty-two minutes. By dividing the diameter of the Earth’s orbit by the time difference, one might then calculate the speed of light.

The calculation was initially done by the Dutch scientist Christiaan Huygens, who calculated that the speed of light is 131,000 miles per second. The discrepancy resulted from mistakes in Roemer’s calculation of the greatest time delay (the actual amount is 16.7, not 22 minutes), as well as from an inaccuracy in his understanding of the Earth’s orbital diameter. The fact that Roemer’s data offered the first quantitative estimate for the speed of light that it was within reasonable bounds, however, was more significant than the precise result.

In 1728, James Bradley, an English astronomer, determined the speed of light by examining star aberrations, or the apparent shift in their positions brought on by the earth’s rotation around the sun. Bradley arrived at a far more precise figure by measuring the angle of this change and deducting the earth’s speed, which he could determine from information available at the time. He determined that light travels at 301,000 km/s in a vacuum.

Continued Measurements

It took several centuries for the measurement of the speed of light to become firmly established, but it wasn’t until the middle of the eighteenth century that everything started to come together. At that point, scientist James Clerk Maxwell unintentionally created light.

When Maxwell made his discovery, he was experimenting with the then-poorly understood phenomena of electricity and magnetism. He found a single, comprehensive theory that could account for all the many facts. He found that changing electric fields can result in magnetic fields, and vice versa, in those equations, laying the foundation for what we now know to be the electromagnetic force.

This makes it possible for electrical waves to generate magnetic waves, which in turn cause waves of electricity to traverse through space while leapfrogging over one another. And when Maxwell attempted to determine the velocity of these so-called electromagnetic waves, he came up with the same figure that researchers had been using to determine the speed of light for generations. As a result, light travels at that speed and is formed of electromagnetic waves, which also describes how rapidly waves of electricity and magnetism move across space-time.

Contrasting the velocity of light in Air and Water

The French philosopher Armand Hippolyte Fizeau was the next to measure the speed of light, and he did so without the use of astronomical data. Instead, he created a device with a beam splitter, a rotating toothed wheel, and a mirror that was positioned 8 kilometers from the light source. He could change the wheel’s rotational speed to let one light beam get toward the mirror while obstructing the other. His estimate of c, 315,000 km/s, was published in 1849 but was not as precise as Bradley’s.

The experiment by Fizeau was improved upon a year later by the French scientist Léon Foucault, who used a revolving mirror in place of the toothed wheel. Foucault’s estimate of c, 298,000 km/s, was more correct and he also made a significant discovery in the process. He discovered that the speed of light in air is faster than the speed in water by placing a tube of water between the revolving mirror and the stationary one. This proved that light is a wave in contrast to what the corpuscular theory of light anticipated.

A.A. Michaelson constructed an Interferometer in 1881 to enhance Foucault’s observations by comparing the phases of the initial beam and the returning beam and displaying an interference pattern on a screen. 299,853 km/s was the outcome.

The ether was a phantom material that light waves were imagined to travel through, and Michelson had created the interferometer to detect its presence. Due to the failure of his experiment, which he carried out with scientist Edward Morley, Einstein came to the realization that the speed of light is an absolute constant that is constant across all reference frames. The basis for special relativity theory was laid out in that manner.

How to Travel Nearly at the Light-Speed?

Particles are launched across space at speeds that are close to the speed of light as twisted magnetic fields break and realign. It is known as magnetic reconnect ion.

As far as we can tell, nothing travels faster than the speed of light, according to Einstein’s theory of special relativity, which effectively places a speed limit on cosmic motion. The problem is that when an item gets closer to light speed, it tends to become heavier and heavier, slowing down its velocity. We currently understand that only very small particles are capable of approaching the speed of light.

Scientists measured a solar eclipse on May 29, 1919, and their findings supported Einstein’s theories. In a recent announcement, NASA listed three methods via which particles can reach incredible speeds:

  • Electromagnetic Fields

Electromagnetic Feilds- abhiexo
Image by OpenClipart-Vectors -Pixabay

In simple terms, electromagnetic fields push charged particles forward in a manner relating to how gravity pulls at mass-containing objects. This is how charged particles are accelerated by electromagnetic fields. Electromagnetic fields have the ability to accelerate particles close to the speed of light.

Even on Earth, we can mimic this process. Pulsed electromagnetic fields are produced by massive particle accelerators, such as those at the Fermi National Accelerator Laboratory of the Department of Energy or the Large Hadron Collider of the European Organization for Nuclear Research. These fields have the ability to accelerate charged particles almost as fast as light. After then, scientists frequently collide these particles to discover what particles and energy are created.

  • Magnetic Explosions

In space, magnetic fields can be found all throughout the solar system and around the Earth. They even direct charged cosmic rays as they swirl over the fields. Near planets, the swift particles also have a number of unintended consequences. Near us, magnetic reconnect ion takes place when the Earth’s magnetosphere, or shielding magnetic field, is pushed against by the Sun’s magnetic field.

The Magnetospheric Multiscale spacecraft from NASA were created with the goal of focusing on learning every component of magnetic reconnection. The mission circles the Earth with four identical spacecraft to observe magnetic reconnection in operation. Scientists can learn more about particle acceleration at relativistic speeds both throughout the universe and around the Earth by using the findings of the data analysis.

  • Wave-Particle Interactions

Wave-Particle Interactions- Abhiexo

Informally known as wave-particle interactions, electromagnetic wave-particle interactions can also cause particles to spin out of control at high speeds. These kinds of interactions are ongoing in near-Earth space and are accountable for speeding particles to rates that can harm the electronics aboard spacecraft and satellites.

Van Allen Probes and other NASA missions aid in the understanding of wave-particle interactions. Van Allen probes monitor wave-particle interactions to improve particle movement predictions and safeguard satellite electronics. This is due to the vulnerability of these sensitive spacecraft components to high-speed particles.

It is also believed that some cosmic rays from sources outside of our solar system are accelerated by wave-particle interactions. A hot, thick, compressed gas shell known as a blast wave is expelled from the star core following a supernova explosion.

We encounter the speed of light in a variety of ways every day. We may observe that when a light switch is turned on and the bulb instantly turns on. Since sound waves move through the air at the speed of light, we can hear it when we play music through our computer speakers or mobile devices. Among the most significant aspects of our life is the speed of light. It’s what makes it possible for us to communicate with one another and perceive the environment around us.

Also read:

Scientists just detected a massive structure 60 times Bigger than the Milky Way!

Milky way galaxy- Abhiexo

Note: Those who love to know and interested in space, solar systems, galaxies; they'll reach Abhiexo (online store) and buy Solar System Planet Posters or other vintage solar system poster.

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