Explore Gravity

 

What is gravity?

Explore gravity:

The attraction between objects with mass. It is responsible for the phenomenon that keeps us and everything else on Earth grounded and influences the motion of planets, stars, galaxies, and other celestial bodies in the universe.

F= Gm₁m_{2 /} R²

 Where, F is the gravitational force between two masses m₁ and m₂

G is the gravitational constant

R is the distance between the the centres of the two masses

 

Who discovered gravity and how?

The discovery of gravity is often attributed to Sir Isaac Newton, an English mathematician, physicist, and astronomer. Newton formulated the law of universal gravitation and introduced it to the world in his work "Philosophic Naturalis Principia Mathematica" (Mathematical Principles of Natural Philosophy), commonly known as the Principia, published in 1687.

Newton's insight into gravity came from his profound observations and analysis of various natural phenomena, along with his mathematical genius. One of the most famous stories associated with Newton's discovery of gravity involves an apple falling from a tree. The story goes that while sitting under an apple tree, Newton saw an apple fall to the ground, prompting him to wonder if the same force responsible for pulling the apple to the Earth's surface also governed the motion of the Moon around the Earth and the planets around the Sun.

Newton's key breakthrough was formulating the mathematical law of universal gravitation, which described how every object with mass in the universe attracts every other object with mass through a gravitational force.

 

Understanding of gravity evolved further

Einstein proved that gravity and acceleration are actually able to change the way in which time travels. For example,with the warping of time due to gravity, people who are on the space station are actually aging slower than everyone else on Earth

Massive objects, such as planets or stars, warp the fabric of spacetime around them, and other objects move along the curved paths in response to this distortion. The warping of spacetime is what we perceive as the force of gravity.

 

    Why gravity is important?

1.    Holding celestial bodies together: Gravity is responsible for the formation and stability of celestial bodies like planets, moons, stars, and galaxies. Without gravity, these structures would not be able to maintain their shape and coherence.

2.    Orbiting and motion of celestial bodies: Gravity governs the orbital motion of planets around the Sun, moons around planets, and satellites around Earth. It enables the precise movements of celestial bodies in our solar system and beyond.

3.    Earth's atmosphere and climate: Gravity holds the Earth's atmosphere in place, preventing it from drifting off into space. This is vital for sustaining life on our planet. Additionally, gravity's effect on air and ocean currents plays a crucial role in regulating the climate.

4.    Tides: The gravitational pull of the Moon and, to a lesser extent, the Sun, causes tides in Earth's oceans. Tidal forces also affect other celestial bodies with atmospheres and oceans.

5.    Black holes and galaxies: Gravity is the force responsible for the formation of galaxies and their structures. It also governs the behaviour of black holes, which are regions of spacetime where gravity is incredibly intense.

6.    Time dilation: According to Einstein's theory of general relativity, gravity can affect the passage of time. In areas of stronger gravitational fields, time appears to pass more slowly compared to regions with weaker gravitational fields. This phenomenon has practical applications, such as the need to account for time dilation in the operation of global positioning systems (GPS).

7.    Space exploration: Understanding gravity is crucial for space exploration missions. Astronauts need to account for gravity when launching and landing spacecraft and navigating through space.

8.    Fundamental force: Gravity is one of the four fundamental forces in the universe, along with electromagnetism, the strong nuclear force, and the weak nuclear force. It plays a key role in shaping the interactions between particles and is essential for the structure and behaviour of matter.

 

Why gravity is not important?

1.    Microscopic scale: On extremely small scales, such as in the realm of quantum mechanics, gravity becomes relatively negligible compared to other fundamental forces like electromagnetism and the strong and weak nuclear forces. At these scales, other forces dominate the behaviour of particles.

2.    Space travel beyond our solar system: When it comes to interstellar or intergalactic space travel, the effects of gravity from individual celestial bodies become less significant. Spacecraft can use gravitational slingshot manoeuvres and rely more on propulsion systems for navigation in these vast distances.

3.    Some extreme environments: In certain extreme environments, such as in the vicinity of black holes or during high-energy particle collisions, gravity may not be the dominant force, and other fundamental forces play a more prominent role.

4.    Theoretical unification: In the realm of theoretical physics, researchers are seeking a unified theory that can explain all fundamental forces, including gravity. Some theories, such as string theory or loop quantum gravity, attempt to incorporate gravity into a broader framework, but achieving a complete unified theory remains a challenging task.

 

Planets warping of spacetime compared to Earth

1.    Jupiter: Jupiter is the largest planet in our solar system and has a mass approximately 318 times that of Earth. Due to its massive size and high density, Jupiter creates a substantial gravity well, causing significant warping of spacetime around it.

2.    Saturn: Saturn is the second-largest planet and has a mass approximately 95 times that of Earth. While it is smaller and less massive than Jupiter, it still produces a considerable warping effect on spacetime.

3.    Uranus: Uranus is the seventh planet from the Sun and has a mass approximately 14.5 times that of Earth. It is less massive than Jupiter and Saturn, so its warping of spacetime is smaller than these gas giants but still notable.

4.    Neptune: Neptune, the eighth planet from the Sun, has a mass approximately 17 times that of Earth. It is a gas giant like Jupiter and Saturn, so its warping of spacetime is comparable to Uranus but not as significant as the two largest planets.

5.    Mars: Mars is a terrestrial planet with a mass approximately 0.11 times that of Earth. Being smaller and less massive than Earth, Mars produces a smaller warping of spacetime.

6.    Mercury: Mercury is the smallest planet in our solar system and has a mass approximately 0.055 times that of Earth. As the smallest and least massive planet, it has the least warping effect on spacetime among the planets.