Category: Space

Neutron Stars- The Most Powerful Stars In Our Universe

What would happen if a star with over 10 to 25 times the mass of our Sun goes supernova? There are two probabilities due to the resulting supernova explosion; one would lead to forming a black hole, and the other leading to the formation of Neutron stars. With the most powerful gravitational field and magnetic force, Neutron stars are spinning balls of collapsed stars that illuminate the night sky. Astronomers have discovered nearly 2000 Neutron stars in the milky way and theorize that there could be over 1 million in our neighbouring galaxies. 

How is a Neutron Star Formed?

In our universe, new stars are formed from the remnants of collapsed stars. The same is true in the case of a Neutron star. Before understanding how Neutron stars were formed, we need to know a little about stars and the cause of a gravitational collapse. Stars comprise millions and billions of hot plasma that is being pushed into the core due to gravity that nuclei fuse. Hydrogen fuses into Helium, thereby releasing energy that pushes against gravity and tries to escape. Stars are quite stable as long as this balance exists. However, over a few billion years, this Helium will get depleted and result in the star growing into a red giant. Medium-sized stars like our Sun will burn Helium into Carbon and Oxygen during the end of their life, swelling into a red giant. These medium-sized stars will turn into white dwarfs.

Gravitational Collapse Resulting in a Supernova

However, for stars that are 10 to 25 times the mass of our Sun, the internal reaction would be far different once the Helium gets exhausted. The balance of pressure and radiation collapses, and gravity will squeeze the star tighter, and the core would burn hotter and faster, resulting in the star swelling hundreds of times. At this stage, heavier elements will begin to fuse; carbon burns to neon in a few centuries. Neon burns to Oxygen in a few months, Oxygen burns to Silicon in months, and Silicon burns to Iron. This Iron ball is nuclear ash with no energy to give and therefore cannot be fused. Without the outward pressure from fusion, the core gets crushed due to the enormous weight around it. 

Due to the collapsing weight of the star, the electrons and protons fuse into neutrons and further gets squeezed together. This is known as a gradual gravitational collapse. Here, an iron ball the size of the Earth gets crushed into a small ball the size of a city. This will result in the whole star imploding with gravity, pulling the outer layers of the star at 25% the speed of light. This implosion bounces off the iron core, producing a massive shockwave with the remnants of the star spewed into space. This is known as a supernova explosion, which is so bright that it could outshine galaxies. After the explosion, what remains is a Neutron star with the mass of over a million Earths but compressed to an object which is nearly 25 km wide. 

The Nature of a Neutron Star

A Neutron Star’s gravity is the second strongest in the universe, first to black holes. If a Neutron star gets denser, it could even become a black hole. Even light gets bent around it, so you can only see the front and parts of the back. They are massively hot as they burn at a million-degree Celsius. Just like planets, Neutron stars also comprise an atmosphere, crust, and core. The crust is very hard as the outermost layers comprise iron leftover from the supernova explosion. On the crust, there are enormous nuclei with millions of protons and neutrons shaped like spaghetti. Physicists call this nuclear pasta which is known to be one of the densest and strongest materials in the universe. Nobody knows what the core of a neutron star might comprise due to its dense nature. Physicists theorize that protons and neutrons might dissolve into an ocean of quarks known as the Quark-Gluon plasma. 

Celestial Ballerinas 

Have you ever seen a ballerina spinning by pulling her arms in? When Neutron stars collapse, they begin spinning very fast, several times per second. PSR J1748-2446ad is one of the fastest spinning neutron stars in our universe, spinning at 716 times a second, which is nearly 25% the speed of light. 

The spin of Neutron stars creates radio pulses that can be detected. These are known as radio pulsars, which are the best-known type of neutron stars. These fast-spinning celestial ballerinas are known as magnetars until they calm down. Magnetars are 1000 times stronger than regular neutron stars, with a magnetic field that is 100 million times stronger than the most powerful man-made magnets. 

The Collision of Two Neutron Stars Forms a Black Hole

The best types of Neutron stars are friends with other neutron stars. While radiating energy like gravitational waves and ripples in space-time, two Neutron stars would collide as their orbits decay. Their collision would result in both stars getting destroyed in a killonova explosion, forming a black hole. The remnants of the explosion and debris of a killonova explosion will mix back into the galaxy. Some of them end up in a cloud that gravity pulls together, leading to the formation of stars and planets. This process would repeat as a cycle.  

Even our solar system is the product of the remains of collapsed Neutron stars. In fact, all the elements in our technological world are built out of the elements Neutron stars made billions of years ago.

Einstein Rosen Bridge- Wormhole Theory

Monica was an inquisitive fifteen-year-old girl who was always in the pursuit of learning more and experimenting with various concepts. She was a very bold teen who never backed down to a challenge and always questioned age-old beliefs and primitive religious ideologies. On a fine Saturday afternoon, Monica finished her assignment that encompassed the core concepts of Einstein’s theory of relativity. She was fascinated by the theory of interstellar travel through Einstein’s Rosen Bridge, popularly known as wormholes. She wanted to know more about this concept, so she turned to her father for an explanation. 

Monica’s father, Richard, was a theoretical astrophysics and cosmologist who often kindled Monica’s interest in Physics and Astronomy. He always made it a point to address his daughter’s queries patiently despite his busy schedule. 

What are Wormholes?

Monica asked, “Hey dad, I have been looking into the concept of Einstein’s Rosen Bridge but couldn’t make heads or tails of it! Can you please explain?” 

Richard replied with a sparkle of excitement in his eyes, “Wow, Monica, I am so glad that you are interested to learn more about this wonderful theory. It would be a pleasure for me to explain this to you.”

He continued, “Monica, to understand the theory about wormholes, you need first to know Einstein’s theory of general relativity and its relevance to the Rosen Bridge. Since general relativity states that the region of space and time can be bent and is not static, Einstein and physicist Nathan Rosan further elaborated on the idea. They proposed the existence of space-time through bridges that connect two different points in space-time. This bridge was coined as the Einstein Rosen bridge.” 

“I understood the concept of the bridge, dad. Can you elaborate on the use of this bridge?” Asked Monica.

“Sure honey, since these bridges connect two different points in space-time, it could reduce the travel time drastically. If you are looking to travel to a place that is several lightyears away, wormholes can make your journey much faster.”

Monica asked, “But dad, don’t the laws of physics state that no object of mass can travel at or faster than the speed of light?”

“Yes, that’s right, dear, but when it comes to the concept of wormholes, it establishes a portal that directly ships you to another point in space-time in an instant. It is kind of like taking a shortcut to your favourite fast-food place.” 

Are there White Holes?

“Wow, dad, that was quite insightful. Can you please tell me more about the principle of how wormholes function?” asked Monica.

The Einstein Rosen bridge theory was further expanded where massive blackholes play a vital role in linking two areas of space. Richard explained, “as we have seen from Einstein’s theory of relativity about black holes, matter and light that gets sucked into the black hole is spat out through a white hole in another region of space or even another dimension, perhaps even a multiverse.”

Monica said, “sounds so cool, dad. Does that mean that white holes exist?”

“No honey, the existence of white holes and wormholes are only on paper; they haven’t been proven. No telescope has spotted a region in space where matter and light are being emitted. Also, there is no proof that black holes are portals to other regions in space or another universe; it is all just speculation.” 

The Scope of Wormholes

“Oh, I see,” said Monica with a disappointed expression on her face. “So, let’s assume that wormholes are real; if so, what are they useful for?”

Richard replied, “sweetheart, if wormholes are real, they can be used for a wide variety of interstellar travel and travel between galaxies in a zap.” They would be like shortcuts to destinations that would normally take hundreds of years to reach, that is assuming that we could travel at the speed of light. Even though an object would travel slower than light inside the wormhole, it would reach a destination before light itself, as the region inside a wormhole is like taking a very easy shortcut to a location. 

“Oh my god, that is so amazing, dad! Hey, tell me what expert scientists have to say about wormholes? Monica said with her eyes filled with excitement.” 

“Did you know that several scientists have theorized some concepts that could suggest that wormholes could exist? Yeah, Stephen Hawking says that wormholes could be all around us, but they would appear microscopically small. Within every piece of matter, including time itself, there could be very small holes and wrinkles that are smaller than an atom. Due to them being so tiny, there is no possible way to travel between or manipulate them.”

Magnetic Wormholes

Monica said, “This is really fascinating, dad. Are there other types of wormholes?”

Richard said, “the Einstein Rosen bridge is the theory of a gravitational wormhole, whereas another type of wormhole is known as a magnetic wormhole. A magnetic field can be transferred from one place to another through a magnetically non-detectable path in a magnetic wormhole. Hey, did you know that physicists in Spain were able to create a magnetic wormhole in 2015? They created a tunnel that enabled a magnetic field to disappear at one point in space and reappear at another. Using metasurfaces and metamaterials, they constructed a tunnel that was able to achieve this near unimaginable feat.” 

“Thanks for this amazing insight dad, you have made the theory of wormholes play like a documentary movie in front of my eyes. I would love to submit an article explaining this concept for my science project.” 

“That’s my girl, remember Monica, the field of science is always ever-evolving, who knows, in the future, we could probably stumble into some mind-blowing evidence that could prove things which are far beyond our current knowledge. Always explore, don’t limit the potential of your brain to mere bookish knowledge, and expand your thinking beyond the horizons of humankind.” 

Tiny Vibrating Strings in the Universe- String Theory Simplified

Gravity has been one of the most pivotal forces that bind planets, stars, and galaxies. Scientists have been keen on understanding the nature of elements through mathematical calculations and analytical methods. Theoretical physicists were unable to make head or tail for several unanswered questions that have baffled them for decades. That’s when Werner Karl Heisenberg, a German theoretical physicist, did extensive research and arrived at string theory. Understanding this theory and deciphering it was like finding a needle in a haystack. The string theory was a single mathematical picture that described all forces and matter. It aimed at addressing various theoretical conundrums with the principle of how gravity works as its fundamental point. 

General relativity proposed by Einstein states that gravity was a reaction of large objects, such as planets, towards the curved regions of space. However, theoretical physicists were not convinced as they thought that gravity had to behave like magnetism. This is because even small particles such as fridge magnets stick as they swap photons with the particles on the fridge’s surface. Physicists understood that gravity lacked this description from the perspective of small particles among the four forces in nature. They could predict the appearance of a gravity particle but were unable to calculate what happens when two gravitons smashed together, as mathematical calculations showed infinite energy was packed into a small space. This meant that the math lacked something; this was when string theory found its place.

The string theory draws a new perspective of the standard description of the universe by replacing all matter and force particles with just a single element. These tiny vibrating strings twist and turn in a complex manner. Although this theory broadens the perspective of our universe, it fails to unify certain aspects in physics as scientists continue to debate on its relevance and scope for improvement today. 

What is String Theory?

Strings can collide and rebound cleanly without implying physically impossible infinities. Quantum mechanics and probability principles were enough to explain the composition of our universe. However, many problems bothered scientists and prevented them from having a good night’s sleep. Quantum gravity was one of the prominent problems in modern physics; it had to reconcile general relativity with principles of quantum mechanics. There were large gaps in developing a consistent theory of quantum gravity due to several problems in black holes, atomic nuclei, and the early development of the universe during that time. One possible solution, which theorists borrowed from nuclear physicists in the 1970s, is to eliminate the problematic, point-like graviton particles. 

String theory is a concrete framework that addresses these pressing questions and others. Point-like particles of particle physics could be modelled as one-dimensional objects known as strings. The behaviour of these strings and the nature of their interaction through space is string theory. There is only one type of string that resembles a small loop or segment of an ordinary string. Picture tying a small string between two poles and striking it. Observe its vibration; through this, you can notice that the string doesn’t vibrate in a particular manner. This is exactly how the string particles interact in the universe. 

All elementary particles are viewed as vibrating strings. Over large distances, the mass, charge and other properties of the string determine the vibrational state of the string. One of the vibrational states of the string gives rise to a quantum mechanical particle graviton; it carries the gravitational force. Therefore, string theory nothing but the theory of quantum gravity. 

How Does Modern String Theory Connect Mathematical Dots?

As science advanced and new discoveries came to light, the String theory was also the subject of modification. The modern string theory was reformulated in 1988 by John Schwarz, an American theoretical physicist, and Andre Neveu, a French physicist. The new string theory was in a league of its own as it did not have to remain consistent with special relativity and quantum theory. This modified theory was the superstring theory that stated that the world comprises three spatial dimensions and one temporal dimension. For the universe to remain finite, time had to be curved as this would require a second temporal dimension. String theorists envision that some multi-dimensional compactification of space existed at every point in space.

Duality, an abstract mathematical relationship between two situations, looks different but could be translated. Theoretical physicists used analogous dualities that bridge unrelated branches in math, such as geometry and number theory. Each operates differently, but dualities enable mathematicians to translate from one another. String theory has the potential to illuminate the dark web by linking different areas of math; this is still up for debate among scientists. Leading scientists believe that string theory still continues to evolve and remains a very productive field of research with the potential to solve long-standing mathematical equations.

Conclusion

Several scientists still debate the string theory’s future, as it has failed to live up to its promise of uniting gravity and quantum mechanics. However, it has become one of the most useful sets of tools in science. If we understand the nature of dark matter and dark energy, it could give us a better perspective of the universe and maybe make string theory more relevant. This is because understanding the dark matter will open up a pandora’s box that would help scientists analyze different aspects regarding dimensions and vibrating strings. The string theory is just a theory and could also be disproved in the future due to new discoveries in cosmology, astrophysics, quantum mechanics, astronomy, or even overall science. 

Why A Ring Around Saturn?

Why a ring around Saturn? Because she’s engaged! As the second-largest planet in the solar system, Saturn is a gas giant adorned with a gorgeous icy ring that adds flair to its personality. It is made up of Hydrogen and Helium gases making up a huge ball that is home to one of the most breath-taking landscapes in our solar system. Saturn is named after the Roman god of agriculture and wealth, also the father of Jupiter. 

What is Saturn Made up of?

Before we understand why Saturn has a ring around it, we need to know the history of how the planet was formed. 4.5 billion years ago, Saturn was formed when other planets in the solar system took shape. Gravity pulled swirling dust and gas in to become this enormous second-largest gas giant in the solar system. At its core, there are dense metals like iron and nickel that are surrounded by rocky material and other compounds solidified by intense pressure and heat. Its core is very stable and integral as it is enveloped by a layer of liquid hydrogen similar to Jupiter’s core but considerably smaller. 

Did you know that Saturn can float on water if dropped in a planet-sized tub? Yes, that’s right, the planet’s average density is less than water due to its gas composition. Saturn does not have a true surface as it comprises swirling gas and liquids deep down. Let us take a journey into Saturn by flying a space drone into the planet’s atmosphere. As the drone flies into Saturn, it would melt and vaporize well before it hits the planet’s surface. This is due to the extreme pressure and temperature of the planet that could crush, melt, and reduce the spacecraft into smithereens. Also, the planet lacks a crust or surface as it is only a ball of swirling gases. 

The Atmospheric Composition

Let us hypothetically design a specific suit that can withstand the hostile conditions on Saturn. As you are dropped into Saturn, you will be able to observe faint stripes, get streams and storms. They will be of different shades of yellow, brown, and grey. You will be swept away by winds in the upper atmosphere that reach a speed of 1,600 feet per second. The pressure will be so immense that it would squeeze gas into a liquid form. But you will not be affected by this as the hypothetically created suit would be able to withstand this pressure. 

As you make your way to the planet’s North pole, you will be mesmerized by a six-sided jet stream. This stream that resembles a hexagon was first observed by the Voyager 1 spacecraft in 1980. This hexagon spans at 20,000 miles across, with a wavy jet stream of wind hitting you at 322 km/hr with a massive rotating storm at the center. Saturn’s smaller magnetic field is smaller than Jupiter’s but 578 times more powerful than Earth’s. It has an enormous magnetosphere that covers the rings and many of the satellites. The magnetosphere behaves like electrically charged particles and is influenced by Saturn’s magnetic field than the solar wind.

How Did the Ring Form?

When Saturn was formed, it is believed that pieces of asteroids and comets of shattered moons broke up before they reached the planet, thanks to its strong gravity. Since these asteroids were very far away from the Sun, they were coated with ice due to the extreme cold. The planet’s ring comprises dust-sized icy grains to large chunks as big as a house or even a mountain. These rings would look white from the surface, with each ring orbiting around the planet at a different speed. 

Saturn’s ring extends up to 175,000 miles from the planet, but the vertical height is 30 feet in main rings. The ring was named in the order they were discovered alphabetically, with the main ones being A, B, and C. Fainter and more recently discovered rings were D, E, F, and G. The rings D, C, and B are close to the inner atmosphere of the planet and rings A, F, G, and E were farther out. Also, there is a faint ring in the orbit of Saturn’s moon Pheobe. 

Saturn’s rings are truly an amazing sight to behold. You can visit a nearby observatory to check out that marvelous sight on the right day. Just make sure to search on the internet and find the day when Saturn will be visible in the right sky and drive to the observatory. 

Delving into Dark Energy and Dark Matter

For the last six decades, scientists at NASA, the Russian Space Agency, and other renowned space research organizations around the world have expanded the knowledge of our universe by a monstrous margin. They have launched a full fleet of telescopes and satellites that have explored various galaxies, planets, and the farthest corners of the universe. As a result, what we considered as fiction 100 years ago is now a reality due to the discovery of new elements and the study of the evolution of the universe from the big bang to the present. 

Wilkinson Microwave Anisotropy Probe, the Spacecraft that Gave Our Universe its DOB

The cosmic microwave background is a record of the earliest version of the big bang. The dark ages are where the first stars and galaxies were formed. We must be ever grateful to the Wilkinson microwave anisotropy probe, which made this measurement and gave a coherent picture of the universe we see today. This probe was enabled astronomers and astrophysics to precisely date the age of the universe, which is 13.77 billion years old. Scientists were also able to understand that atoms only made 4.6% of the universe, with the remaining being dark matter and dark energy. The universe consists of regular matter, dark matter, and dark energy. Regular matter constitutes just 5%, consisting of atoms that make up stars, planets, humans, and every other visible object in the universe.

Galaxies, solar systems, and planets are held together by gravity, the universal binder; however, something doesn’t quite add up as galaxies are achieving something that defies gravity. Galaxies are rotating at such speed that the gravity generated by the observable matter doesn’t hold them together as they should have been torn apart long ago causing a cosmic catastrophe. This leads scientists to believe that something that is not observable is in play.

27% of the Universe is Dark Matter

We look up in the universe and see the effects of gravity, how it binds stars, planets, and galaxies together. Now, picture a simulation that lets you re-create the events in the history of the universe. Let’s add up all the comets, black holes, asteroids, stars, and everything we know about to account for the gravity we see. Now add dark matter, the extra gravity, Eureka, the universe becomes what we see. That’s why we know that dark matter is real; we don’t know what it is, but we know that it’s there because we cannot make the universe we see today unless the dark matter is added into the simulation as it perfectly matches with the gravity. 

Particle physicists are convinced that there is an exotic particle that doesn’t interact with light, telescopes, or any other equipment but has gravity. These particles are invisible to us but are attracting matter into them and interacting with other elements in a unique and accelerated way. These exotic particles are known as dark matter, which forms the bulk of a galaxy’s mass and the foundation of the universe’s large-scale structure. The nature of dark matter is that it doesn’t emit, absorb, or reflect light, thereby making its presence invisible to the universe. However, its presence is known due to its gravitational pull on the visible matter in space. 

Scientists theorize that dark matter could not be matter at all but the gravity from ordinary matter from a nearby other universe or multiverse whose gravitational influence we feel. Mind-blowing, isn’t it? However, there is no hard data of this, but there are theoretical, philosophical reasons to think that a multiverse exists. The first observation of the existence of dark matter was by the Chandra X-ray Telescope in 2007 when it observed the bullet cluster of galaxies. 

68% of the Universe is Dark Energy

The Hubble Space Telescope observed very distant supernovae showed scientists that there was a time where the universe was expanding at a much slower rate than today. However, the expanding universe has not been slowing down but has accelerated by a significant margin. No scientist could rationally or theoretically explain this phenomenon, but they knew that something was causing this expansion. Scientists discovered a mysterious pressure in the vacuum of space acting opposite to the force of gravity. This pressure was coined as dark energy, a placeholder term to describe what was observed. No known force could stop or slow down the expansion of the universe.

In fact, in theory, space cannot accommodate or allow this rapid expansion of the universe as it might tear in an unimaginable way. Leading scientists and astrophysics are still baffled at this fact as they cannot explain the nature of dark energy. This energy is needed to measure the geometry of space with the total matter in the universe. 

A Breakthrough that Could Re-define Our Understanding of the Universe

The universe is far from being fully understood, and there are numerous theories as to what dark matter and dark energy actually are. Scientists have been racking their brains about what these entities are. In recent times, new methods could detect these energies, thereby leading to a breakthrough in our understanding of the universe. In astrophysics, there is always a capacity to measure something, even if it is unknown to us. For instance, you could measure something falling to the ground by assessing its velocity but not know what the particle is. Likewise, we can measure the sun moving across the sky and build calendars based on that and not know that the Earth revolves around the Sun (This is what our early ancestors did). 

Rebecca K Leane is an astroparticle physicist at the SLAC national accelerator laboratory at Stanford University. She believes that Jupiter is an ideal candidate to detect dark matter. It has a large surface area that enables it to capture more incoming particles than any other planet in the solar system. 

Exoplanets can also be used to detect dark matter as it does not involve the use of new instruments. When the gravity of exoplanets captures dark matter, it travels to the planetary core to release its energy as heat. The more the dark matter is captured, the more it should heat up the atmosphere. This heat could be captured by NASA’s James Webb Space Telescope, an infrared telescope that is scheduled to launch in November 2021. This telescope is planned to succeed the Hubble and give rise to much larger discoveries that could re-shape the understanding of our universe.

Conclusion

With the launch of the James Webb telescope, scientists could observe various statists of galaxy evolution and compare these observations and analyze theories of the role that dark matter played in that process. In 2025, NASA is planning to launch the Nancy Grace Roman Space telescope designed to unravel the secrets of dark matter and dark energy. It would enable scientists to image exoplanets, explore topics in infrared astrophysics. If this project is successful, it could pave the way to several groundbreaking scientific discoveries that could change the understanding of our existence in the universe! 

Hey! Who Turned Off The Lights: Eclipses Explained

One of the most spectacular sights to behold once every 18 months, solar and lunar eclipses are fascinating to the human eye. However, a total solar or lunar eclipse would occur only once in 50-80 years. Depending on where you are located on Earth, some locations are like a diamond box in a Cricket stadium that enables you to view a total eclipse in all its glory. When people observed the Moon during an eclipse, they saw the Earth’s shadow on the Moon, which led to the discovery that the Earth was round.

Scientists still continue to discover more about the Moon from lunar eclipses. In 2011, NASA’s lunar reconnaissance orbiter obtained data of how instantly the Moon’s dayside cools during a lunar eclipse. This helped scientists understand the Moon’s surface better. Also, solar eclipses pave the way for astrophysicists to learn more about the Sun’s corona, its top layer.

Both the solar and lunar eclipses depend on the position and movement of the Earth and the Moon while orbiting the Sun. The Moon obstructs the Sun’s rays during a solar eclipse, and its shadow falls on Earth. In a lunar eclipse, the inverse happens, where the shadow of the Earth falls on the Moon, causing it to appear red. Come, let’s dive into the principle of eclipses and how they occur.

How Does the Moon Revolve Around the Earth?

To understand the cause of Eclipses, we need to understand how the Moon orbits the Earth. If you are an avid sky gazer, you might notice that the Moon keeps the same side facing our planet. This is because the Moon is tidally locked to our planet as it orbits. Most planets that are relatively close to each other in orbit are tidally locked in orbit with synchronized rotation. For instance, the planet Mercury is tidally locked to the Sun due to its close proximity and the enormous gravitational force and mass of the Sun.

The Moon orbits Earth with a 5-degree tilt; its orbit determines the portion of the Moon that is visible to the Earth. For instance, if the Moon reaches point B in the image below, then it would appear crescent-shaped when viewed from the Earth. This is because the side of the Moon exposed to the Sun is only faintly visible from Earth, thereby appearing as a crescent. The same principle applies to half-crescent, half-moon, and gibbous Moon. The whole cycle of the Moon’s orbit around Earth is 27.5 days, approximately 28 days. 

What is a Solar Eclipse?

Now that we know how the Moon revolves around our Earth and how its orbit impacts our perception of it, it would be easy for us to understand how solar eclipses occur. When the Moon orbits Earth, its orbit also traverses between the Sun and our Earth. At this moment, our Moon blocks the sunlight that reaches us and results in a solar eclipse. The Moon casts a shadow onto Earth.

As the Moon obstructs the Sun’s rays, its shadow gets smaller as it reaches Earth. Umbra is the dark centre of the Moon’s shadow. People who are witnessing a total Solar Eclipse will be standing in the umbra. Penumbra is the lighter outer part of the Moon’s shadow. People who stand in the penumbra will only see a partial eclipse due to the outer shadow. A total solar eclipse is an umbral eclipse, and a partial solar eclipse is known as a penumbral eclipse. A perfect total solar eclipse will look like a ring as the Moon obstructs the Sun’s rays. Since the Moon is smaller than the Sun, the outer portion of the Sun’s rays would seep through the Moon’s edges, making it appear like a beautiful ring studded with a precious gemstone. 

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A total solar eclipse usually occurs in certain parts of the globe that are perfectly positioned under the umbral shadow of the Moon. They occur once in two years, and people in certain locations could be fortunate enough to see total solar eclipses more frequently than others due to their proximity to the umbra. Unlike lunar eclipses, solar eclipses last for a few minutes. If you plan to see the Sun during an eclipse, think again, as the Sun’s harmful rays could damage your retina badly, causing permanent blindness. Make sure to use solar viewing goggles or a solar viewer to enjoy the show. 

What is a Lunar Eclipse?

As Earth’s natural satellite, Moon governs many aspects of our planet, from marking festivals to affecting tidal currents. When manifesting as a Full Moon, the cold, rocky body comes directly opposite to the Sun. When the Earth comes between the Sun and the Moon, it blocks sunlight from reaching the Moon. This specific alignment casts the Earth’s shadow on the Moon’s surface, causing a total lunar eclipse (the Earth eclipsing the Sun’s light from the Moon). Hence, a total lunar eclipse requires a Full Moon and the straight alignment of the Sun, Earth, and Moon. 

Full Moons come around every month roughly. But why don’t we get to see the lunar eclipse every other month? Since the Moon’s orbit is inclined by 5° to the Earth’s orbit around the Sun, it usually passes above or below Earth’s shadows, totally unaffected by them. Only around two to four times a year, the Moon comes in the path of the Earth’s shadows causing either partial or total lunar eclipse (governed by the portion of the Moon affected by the Earth’s shadows). 

Well, if the Earth blocks sunlight from falling on the Moon’s surface, how are we still able to see it? Thanks to the bending of light waves, sunlight passes the Earth’s atmosphere and lights up the Moon’s surface. Add to that the dynamics of light- refraction, scattering and absorption, the Moon appears deep red during the lunar eclipse. Unlike a solar eclipse, you don’t need aid to watch the Moon on a lunar eclipse. Your bare eyes will do!

Myths and Superstitions about Eclipses

Humans have always built cultural and religious myths around celestial events – eclipses are not an exception. 

• Some believe that solar eclipses produce harmful rays capable of robbing one’s eyesight. But scientists disregard the notion on the grounds that the faint light crossing 150 million kilometres of space can cause, at the worst, retinal damage but not blindness. 

• It is widely believed that pregnant women shouldn’t watch the eclipse as its radiation might damage the foetus. Scientists completely dismiss this myth stating that the electromagnetic radiation reaching the Earth from the Sun is perfectly safe.

• Another classic myth is that eclipses will poison any food prepared during the event. Experts suggest not to pay heed to this folklore and keep going about your life as any other normal day. 

• A few religious texts strongly recommend against taking baths during the lunar eclipse. Since this is a baseless superstition, please take a bath for the sake of those around, if not for you.  

• “You should not sleep during the eclipse,” Indian astrologers point out, considering the event to be a bad omen. Yet, science reaffirms, “You sleeping on your bed has nothing to do with the Moon.” 

We might have come far from the ages of folktales and misinformation, but myths and superstitions continue to persist among us. Now that you know how eclipses occur keep looking forward to the numerous eclipses ahead without fear or concern, but only wonder and excitement. 

Why Are Planets Round?

Have you ever wondered why planets are shaped round? Why aren’t they shaped like pyramids, cubes, or discs? Well, if they were shaped like discs, it would surely be a paradise for flat earthers. 🤣😂 Jokes apart, let’s understand the reason why planets are spherical or oblate spheroid in shape. 

When the solar system was formed, planets formed from the remnants of the protoplanetary disc that comprised of asteroids. These asteroids are large space rocks that bonded together to form the planets we see today. However, you may wonder, although each planet does not constitute just rocks but also gases, why do all elements bind together in the form of a sphere?

Why a Sphere?

Well, the simple answer is gravity. Around 4.5 to 5 billion years ago, space rocks from the protoplanetary disc that orbited around the Sun were the building blocks for planets. This protoplanetary disc was formed due to the aftermath of the birth of our star, the Sun. When large space rocks or space debris and gases bump on each other, they bind together to form large planet-size objects. Over a period of time, these large rocks gather enough mass to have gravity, the key force that holds elements together in space. Once the planet is big enough, it automatically begins to clear a path around the star it orbits. 

Gravity works in one way; it pulls equally from all sides, specifically from the centre to the edges. When materials of large mass bind together, gravity starts acting on them in this manner, and they clump together to form a sphere. Whether it is just space rock or high-density gas and space debris, gravity acts in the same manner and pulls materials inward, giving them a spherical shape. Gravity holds planets together, it’s the universal glue.

Are all Planets a Perfect Sphere?

Not really; most planets are slightly bulged in the middle, similar to a basketball. For instance, our Earth is slightly flat at the poles but bulged along the equator, giving it the shape of an oblate spheroid. Some planets in our solar system, like Mercury and Venus, are the roundest among all, whereas others are thicker in the middle. For instance, Saturn and Jupiter are thicker in the middle.

Try this, soak a tennis ball in water and throw it in the air by giving it a little spin. What do you observe? The water on the ball would dissipate along the outer edges in a sprinkling manner. This is the same in the case of planets too, when large planets spin, materials on the outer edge move faster than the ones on the inside to keep up. This is because things along the edge have to travel the farthest and the fastest. 

Saturn and Jupiter are large planets with a fast spin; this results in a large bulge along the middle like an extra width. This width is known as the equatorial bulge. Saturn is the planet that is thickest around the middle with a 10.7% bulge and Jupiter with a 6.9% bulge in our solar system. 

Gravity, the binding force in the universe, always acts inward; that’s why all materials accumulate and bind together form as a sphere and not as a pyramid, cube, or disc. This law applies to not just the planets in our solar system but to all planets in the universe. 

The Moon, A Perfect Soulmate for Earth

Thousands of poems, millions of admirers, an object that lights up the lives of star-crossed lovers, the Moon. Have you ever wondered how this thing of beauty has had a profound impact on our lives? Oh, I am sure that a 4-billion-year-old relationship between our Earth and the Moon would redefine true love. Here is a wonderful story of how two planets that were meant to be, collided with each other and became entangled in the web of love. This collision was one reasons why our Earth transformed from a barren Hell into a paradise beaming with life. 

Proto Earth, a barren planet

4.5 billion years ago, proto-Earth, which formed from the remnants of swirling gas and dust, revolved around infant Sun. The planet was a barren hell filled with lava due to the rise of hot magma from the planet’s mantle. The atmosphere comprised harmful gases erupting from volcanos, and there was no protection from asteroids and space debris. Several asteroids and debris hit young proto-Earth as they revolved around the newly formed Sun. For millions of years, our planet, which we now call home, remained lifeless and uninhabitable. 

The collision that was meant to be

Around 4.5 to 4.6 billion years ago, a planet named Thea revolved around the young Sun, its orbit nearly along Proto-Earth. It was a planet the size of Mars and travelled at the speed of 4 km/second. Due to the gravitational influence of either Venus or Jupiter, it headed towards a collision with Proto-Earth. Thea struck Earth at a 45-degree angle, at the speed of 8,900 miles per hour. The collision resulted in the ejection of pieces of Proto-Earth and Thea. The Earth’s gravity slowly drew some particles. A huge chunk of rocks began slowly forming into a small planet by accumulating the remnants of the proto-planetary disc that had formed due to the collision. This small planet, the Moon, got tidally locked to the Earth and began revolving around it. This whole process would have taken a hundred million years to happen. 

The collision between Thea and Proto-Earth had slightly tilted Earth’s position and stabilized its orbit around the Sun, thereby forming a perfect orbit in the habitable zone of the star. Before the collision, Earth was spinning faster with no probability of a stable atmosphere forming. The collision slowed down the Earth’s rotation and stabilized it further. If Thea had struck Earth head-on, it would have resulted in both planets being destroyed instantly, creating a short-lived asteroid belt between Venus and Mars. In January 2016, there was evidence that confirmed the presence of the same materials, which turned out to be Thea’s remains, found on both the Earth and the Moon. 

The formation of the Moon and Alternate hypothesis 

Lunar rock samples, retrieved from Apollo astronauts, had a startlingly similar composition to Earth’s crust. This confirms that the formation of the Moon was likely due to a violent event. The Moon’s formation from the resulting collision between Thea and the Earth is known as the Giant-Impact hypothesis, which is widely accepted by scientists today. However, let us look into three other hypotheses that existed from the beginning. 

The first hypothesis describes that a single planet body split into Earth and Moon. The second one speculates that the Moon was captured by the Earth’s gravity, which was the case for most outer planets. The third hypothesis describes that the Moon’s origin formed from the remanets of the protoplanetary disk that accreted. 

An inseparable bond that binds our life force

The Moon helps the Earth rotate in its axis and keep it in perfect orbit. Although most asteroids that are aimed close to the Earth’s orbit usually get caught by Jupiter’s massive gravity, some smaller asteroids land on the Moon. Without the Moon, there would be no environment for many coastal animals to survive as our oceans would have smaller tides, thereby preventing crabs, starfish, turtles, and snails from reproducing and surviving. The temperatures on Earth could vary erratically as the Earth’s axis would tilt by 45 degrees or more. There could be no tilt that could result in no seasons or a major tilt that could result in extreme seasons, perhaps an eternal ice age.

Without the Moon, the Earth’s rotation could slow down further, resulting in far shorter days and more days in a year. We must always celebrate the inseparable bond between the Moon and our Earth. Their strong relationship helps humans thrive. That fortunate collision has helped the Earth stay in perfect orbit and given birth to the evolution of the life we see today. Many scientists theorize that without the Moon, life on Earth may not have evolved as we know it. This is because the Earth would have had a far different orbit around the Sun, leaving it either too hot or far too cold for life to exist. Thea was a planet that sacrificed itself to give us life. It is this 4-billion-year-old relationship between these two lovebirds that helps us evolve and thrive on this planet.

Into Interstellar Space with Voyager

Have you ever imagined yourself leaving the Earth, travelling into outer space, visiting other planets, and eventually leaving the solar system to view the universe in all its glory? Well, Voyagers did just that! Come, let’s take a journey into interstellar space with Voyager.

Voyager the Journey and Beyond

In the early 1970s, NASA had a stellar plan to study outer planets of the solar system and gain a deeper knowledge of them. They were wondering how to build a space probe that could hover through space. With the information gathered from the Pioneer 10 spacecraft, scientists at NASA’s Jet Propulsion Laboratory were able to design the probe such that it could take immense radiation from Jupiter with enhanced radiation shielding. On July 1st 1972, the project to launch Voyager 1 and Voyager 2 for the purpose of deep space exploration began.

Equipped with 16 hydrazine thrusters referencing instruments and gyroscopes, the two Voyagers had instruments to study objects in space and bring to light the best pictures of the cosmos through its cameras.

Take off… the beginning of an awesome journey

On September 5th 1977, Voyager 1 took off from NASA’s Kennedy Space Centre in Florida. Although Voyager 2 probe was launched a month before, Voyager 1 would be the first to reach Jupiter and Saturn due to its trajectory. Scientists at the Kennedy Space Centre and employees of NASA’s jet propulsion laboratory watched the rocket break through the stratosphere and reach outer space. Voyager 1 sent the first picture of the Earth and the Moon on September 6th 1977, a trickle of tear rolled down the eyes of scientists and engineers as they saw the image.

Flyby of planets in the solar system

Travelling at the speed of 17 kilometres per second, Voyager 1 reached Jupiter on March 5th 1979. It was a sight to behold; it captured images that helped scientists decipher the giant red spot and conclude that it is the eye of a huge storm. It also uncovered other strange phenomena that inflated Jupiter’s magnetic field due to ions stripping from the planet’s surface and creating a torus around it. This acts as an electric generator in Jupiter’s magnetic field.

Voyager encountered Saturn, the ringed planet, on November 9th 1980 and captured its rings in the most magnificent picture. It also flew by Titan, one of Saturn’s moons, and discovered the possibility of seas of liquid methane and ethane on its surface. Voyager 2, on the other hand, reached Saturn nearly a year later in August 1981 and made it to Uranus in January 1986. It made a phenomenal discovery of 11 new moons orbiting Uranus and took pictures of them.

In August 1987, NASA’s deep space network completed expanding the three big dishes that enabled engineers and scientists at the laboratory to better communicate with the two Voyagers. Voyager 2 made yet another startling discovery of six new moons when it encountered Neptune in August 1989. In the meantime, Voyager 1 was on its way towards the end of the solar system. You may ask, why didn’t the Voyagers encounter Pluto? That’s because the primary objective of the Voyager mission was focused on exploring Jupiter and Saturn for Voyager 1 and Uranus and Neptune for Voyager 2.

Are we just a speck? The Pale Blue Dot

On valentine’s day 1990, NASA’s engineers turned the camera of Voyager 1 towards Earth just before disabling the camera to conserve energy. The camera captured the image of a pale blue dot with its size hardly a fragment of a pixel. This image shook the whole of humankind as it was a clear depiction that the human race is just a speck of merely irrelevant species in this vast humongous universe that spans to a diameter of 93 billion lightyears (observable). (nine thousand three hundred crore lightyears).

First man-made object to enter interstellar space

On February 17th 1998, Voyager 1 became the farthest ever human-made object from the Earth, beating the Pioneer 10. The termination shock is a boundary that separates the solar wind and the Heleosheath; it is the outermost region of the solar system. At this point, the solar wind slows down and heats up abruptly. Scientists and engineers at NASA could not communicate with Voyager 1 as ground antennas were not scheduled to capture the data that the spacecraft was listening to. However, after a while, NASA’s experts were able to connect back to the Voyager as it entered the Heleosheath. They were able to measure the analyze the measurements and nature of the spacecraft only when Voyager 2 crossed the termination shock three years later.

The Heliosphere is the region outside the solar system that resembles a bubble that is inflated by plasma emitted by the Sun. This region ends at a point known as the Heliopause, which is exposed to the particles and ions of deep interstellar space. Picture this, you are visiting another country and are going through two different checkpoints, the security checkpoint and the immigration and customs checkpoint. This concept is somewhat similar and also applies to both Voyagers that left the solar system.

On August 25th 2012, the Voyager 1 becomes the first human-made object in the history of mankind to leave the solar system and enter interstellar space, followed by Voyager 2 on November 5th 2018. The Voyagers collect detect the intensity of the cosmic space and the interstellar magnetic field around the heliosheath and send data back for our scientists to rack their brains about. Scientists understand the nature of the coronal mass ejection thrown out by the Sun, causing the Voyagers to ring.

For the universe to see… The Golden Record

Where would the two Voyagers go? You may ask, well, their trajectory is not pointed to any nebula, specific star or a planet, but it travels aimlessly through interstellar space at the speed of 62,140 km/hour. Oh! You might think that is fast, but it is nothing compared to the speed of light, which is 300,000 kilometres per second. Since most starts in our neighbourhood are around 4-8 light-years away, it would take the Voyager a whopping 73,000 years to reach Proxima Centauri at its current speed of 17 km/second. That is if its trajectory is aimed towards Proxima Centauri.

The odds that one of the Voyagers would come in contact with intelligent life in this colossal universe is highly minuscule. Scientists at NASA, along with Carl Sagan, decided to add a Golden phonographic record for any intelligent life to decipher. This golden record contains a message from the human race that includes greetings in various languages, sounds, music, thoughts, and images of Earth and life. Jimmy Carter, the US president at that time, also shared a small message, “We are attempting to survive our time and may live into yours, having solved the problems we face, to join a community of galactic civilizations.”

Placing the Golden record on both the Voyagers was truly a remarkable idea. Experts at NASA have included some simple ways how the record can be played and accessed through pictorial representations. Also, the record is built in such a way that data could be extracted from it even after a billion years (100 crore years). The record also includes an hour-long brain wave of Carl Sagan’s wife.

A Tribute to Carl Sagan 

Although he lived a relatively short life, Carl Sagan was one of the most influential and brilliant astrophysicists. He was also a cosmologist, astrobiologist, and science communicator. He has written several books that continue to influence students and young scientists to pursue their dreams in the field of Scientology. His inquisitiveness, scientific thinking, and advocacy has propelled several kinds of research and built a platform for young scientists to emulate.

Here is the link to the speech by Carl Sagan in Cornell lecture 1994 regarding the pale blue dot.

A Tribute to Stephen Hawking

Meet the man who gave a new definition to the universe, a cosmologist, a passionate physicist, and a genius who was born to mesmerize the world with his voracious intellect. Stephen William Hawking was one of the world’s greatest theoretical physicists and an indispensable asset in the field of cosmology and particle physics. 

A Legend is born 

Stephen Hawking was born on 8th January 1942 to a relatively well to do family in Oxford, England. In his initial years, he was not academically successful but eventually showed excellence in scientific subjects and mathematics. He was also known as Einstein during his school days. He studied at Oxford university college, which was an utter cakewalk for him as he found most subjects ridiculously easy. However, he went into depression when he was diagnosed with motor neuron disease, Amyotrophic Lateral Sclerosis (ALS), during his graduate years, and doctors gave him only two years to live. Despite this severe blow in his life that rendered him speech impaired and physically challenged, Hawking cheated death and soared to great heights with his thoughts pervading in every young astrophysicist well past his demise. 

New Beginnings

Hawking came to Cambridge to study with one of the world’s famous cosmologists back in the 1960s, Sir Fred Hoyle. 

Hoyle strongly believed in the steady-state theory, which inferred that the universe has no beginning or end. This theory stated that matter would continuously be created as the universe expands, in utter disagreement with the big bang notion of an indefinitely dense initial state. The steady-state theory was widely accepted among the most renowned astrophysicists at that time. 

Young Hawking was eager to flex his neurons and genius intellect; he called his doctoral thesis properties of expanding universes. During his first months at Cambridge, he was interested in Narlikar’s calculations and began hanging around his office opening discussions and sharing ideas. He became more engrossed with Narlikar’s difficulties with the project Hoyle assigned. 

In a talk at the prestigious royal society, Hoyle discussed the latest ideas based on Narlikar’s calculations. After his speech, he asked the crowd whether they had any questions, flaunting his appreciation with a sheepish grin filled with pride. Much to his dismay, Hawking stood up and said, “the quality you talk about diverges.” Filled with ego, Hoyle says, “How do you know?” Hawking replies, “Because I worked it out.” Hawking goes on to showcase his paper summarizing mathematical methods he had used and proved the divergence of Hoyle’s equations. 

Hoyle was furious as an embarrassed laugh passed through the audience. He had his work refereed openly by an unknown post-graduate student. 

Limitless Intellect

One of the Oxford tutors supervising Hawking’s work in statistical physics assigned several problems from a textbook. Only to be greeted with a list of mistakes in the textbook marked clearly with a valid explanation. His mind knew no bounds as he harnessed extreme intellect that enabled him to decipher even the most complex calculations and postulates into simple yet understandable concepts. 

As Hawking was nearing his end of term at Oxford, he met with a terrible fall in the staircase due to the beginning effect of ALS, which resulted in a temporary memory loss. However, even ALS stood no match, as Hawking passed with flying colours! 

A New Perspective of the Universe

Albert Einstein predicted the existence of black holes through his theory of relativity. Black holes stemmed from massive stars that collapsed. However, this black hole theory was not well understood by scientists due to the lack of exploration and complex nature of the concept. 

Hawking took it a step further and notched it down for easier understanding. He christened a new definition to the black hole theory that established the existence of black holes as reality and not just a theory that could be debunked. With his remarkable brain, he proved certain rigorous mathematical theorems of Einstein’s equations for gravity. Under general circumstances, he showed that there were places where equations broke down and coined them singularities. The region inside a black hole, in which even light cannot escape, is known as a singularity. 

Yes, Black holes Shrink, Hawking Radiation

In his initial research, Hawking was of the strong impression that the size of a black hole remains constant and never changes. However, after some vigorous research and rethinking, he proved that black holes could shrink as they radiate energy, thereby reducing mass. This energy that radiates is known as Hawking radiation.

Hawking theorized that this radiation from virtual particles was constantly popping into and out of existence in the bizarre quantum realm. This happens in matter-anti-matter pairs, where one has positive energy and the other with a negative. Hawking also emphasized that black holes have tendencies of evaporating or boiling themselves away in a brilliant burst of energy equal to a million 1 megaton hydrogen bombs, astounding, isn’t it? 

Gracefully Dealing with Criticism

A successful person is always prone to criticism; Stephen Hawking was not new to that. He faced criticism from other scientists who coined the black hole information paradox. This paradox was a puzzle with the combination of quantum mechanics and general relativity. 

Hawking proved that once a star dies, all its mass would collapse into a single point of infinite density that results in a singularity. The information paradox stated that once the black hole collapsed, all information is lost, thereby violating the principle of quantum physics that information cannot be destroyed as it stays constant. Hawking debunked the paradox with his witty argument that information is not lost but is encoded in particles emitted by the radiation. 

Hawking’s contributions to physics are a force to be reckoned with. His level of intellect was beyond comprehension and blew the minds of renowned cosmologists and scientists. He established a strong foundation for scientists in the future by bridging several gaps in quantum cosmology, black holes, thermodynamics, and various riddles in the universe. His contributions would pave the way for future research and reshape our understanding of the universe.