Category Archives: Astrophysics

aliens, Astrophysics

Are we alone?

About 13.8 billion years ago, there was nothing..and then, bang! The universe was created. When the universe was only 200 million years old, it gave birth to stars. Slowly stars became very common in the universe. After many many years, our star, the head of our solar system, the Sun was born. The solar system was a violent place then. The mass emitted by the sun created small rocky bodies, one of which was the Earth. The Earth is a little over 4.5 billion years old, with its oldest materials being 4.3 billion-year-old zircon crystals. To date, we have no evidence as to how life came into being. Theories say that bacteria were brought to the earth by an asteroid, some say that it was aliens who ruled the planet and left it after mass destruction, whereas some theories say that there was a chemical reaction between water and organic elements (which created amino acids) on being hit by lightning.

Unicellular cells developed to form complex organisms like us which had the ability to think and reason. As there was a development in education and space sciences, one major thought kept hitting everyone’s mind – “Are we alone?”. The Universe is a huge place. It is a waste of space if we’re the only ones living in it. Come on.. there have to be aliens right?

There are about 100,000,000,000 galaxies in the known universe. Each galaxy has 100,000,000,000 to 1,000,000,000,000 stars. Planets also appear to be common in every solar system observed so far. The milky way itself has 400 billion stars i.e. 10,000 stars for every single grain of sand on earth! Then why have we not been contacted by aliens till now?

Drake’s Equation and Fermi Paradox

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drake equation

The Drake Equation is:
N = R * fp * ne * fl * fi * fc * L

where:
N = The number of broadcasting civilizations.
R = Average rate of formation of suitable stars (stars/year) in the Milky Way galaxy
fp = Fraction of stars that form planets
ne = Average number of habitable planets per star
fl = Fraction of habitable planets (ne) where life emerges
fi = Fraction of habitable planets with life where intelligence evolves
fc = Fraction of planets with intelligent life capable of interstellar communication
L = Years a civilization remains detectable

You see, it’s so easy to calculate the number of alien civilizations in our galaxy! Hahaha..just kidding. The Drake Equation appears extremely pleasing on a piece of paper but is unrealistic (according to me). So do we conclude that we’re alone? Not so early.. We are probably forgetting about The Fermi Paradox.

The Fermi paradox is named after physicist Enrico Fermi, which is the apparent contradiction between the lack of evidence and high probability estimates for the existence of extraterrestrial civilizations. It is a conflict between probability and evidence. It also states that we could be protected under a shield that does not allow us to contact other intelligent beings.

aliens, Astrophysics

WOW! Signal

Are we alone? Do aliens exist? These are some questions which keep bugging us all the time. In the late 1900s, technology was developed enough to give scientists a sense of confidence about extraterrestrial life.

How strange would it be if there were aliens? “We are alone” and “There’s somebody out there” are two possibilities, each equally scary. To address this major dilemma, scientists initiated a project called SETI—the Search for Extraterrestrial Intelligence—in 1997. The purpose of this mission is to send and receive radio signals from intelligent life in deep space. Beyond SETI, numerous other radio telescopes have been searching for similar signals.

In 1959, Cornell physicists Philip Morrison and Giuseppe Cocconi speculated that any extraterrestrial civilization attempting to communicate via radio signals might use a frequency of 1420 megahertz. This frequency is naturally emitted by hydrogen, the most common element in the universe, and therefore likely familiar to all technologically advanced civilizations. In 1973, after completing an extensive survey of extragalactic radio sources, Ohio State University assigned the now-defunct Big Ear telescope to SETI.

On August 15, 1977 The Ohio State University’s Big Ear Telescope received a weird signal which couldn’t have been created naturally. The signal appeared to come from the constellation Sagittarius and bore the expected hallmarks of extraterrestrial origin. Astronomer Jerry R. Ehman discovered the anomaly a few days later while reviewing the recorded data. He was so impressed by the result that he circled the reading on the computer printout and wrote the comment Wow! on its side, leading to the event’s widely used name.

The Signal

The entire signal sequence lasted for the full 72-second window during which Big Ear was able to observe it, but has not been detected since, despite several subsequent attempts.Wow_signal_profile.svg

This represents the intensity variation of the radio signal over time, measured as unitless signal-to-noise ratio. A common misconception is that the Wow! signal constitutes some sort of message. In fact, what was received appears to be an unmodulated, continuous wave signal with no encoded information; essentially a flash of radio energy.

Two different values for the signal’s frequency have been given: 1420.36 MHz (J. D. Kraus) and 1420.46 MHz (J. R. Ehman), both very close to the value of 1420.41 MHz of the hydrogen line.

Hypothesis

  1. Interstellar scintillation of a weaker continuous signal : This basically means that the signal might not be real but an illusion like the twinkling of stars.
  2. Reflected signal : An earth sourced signal could have been reflected by some debris in space.
  3. Hydrogeb could surrounding two comets : Antonio Paris proposed that the hydrogen cloud surrounding two comets, 266P/Christensen and 335P/Gibbs, now known to have been in roughly the right position, could have been the source of the Wow! signal.

Well, the signal couldn’t be replicated again and there is no definite information about its source. Could they be aliens? Nobody knows!

These efforts are driven by the profound curiosity and desire to answer one of humanity’s oldest questions: Are we alone in the universe? The discovery of extraterrestrial intelligence would revolutionize our understanding of our place in the cosmos, while the confirmation of our solitude would deepen the mystery of life’s origins on Earth. Regardless of the outcome, the quest to find intelligent life beyond our planet continues to inspire scientific innovation and exploration.

Astrophysics

Astrophysics

In the beginning, there was eternal darkness. And then, bang! An explosion brought forth an endlessly expanding existence of time, space, and matter. Every day, we discover something new, further than ever imagined, beyond the limits of our existence.

Our universe is a magically unbound expanse of space and time brimming with endless possibilities. Imagine a theoretical tunnel providing shortcuts through space and time, or a three-dimensional hole pulling in all light. Picture blue balls of fire undergoing nuclear fusion, becoming heavier, expanding into red giants, and finally exploding due to a collapse under their own weight.

But before venturing into outer space, we must understand science. “Science is a body of knowledge and a method of how we learned that knowledge.” Science teaches us that our assumptions might be incorrect. We need to observe the universe, scrutinize every phenomenon, and make educated guesses about what is happening and why, to uncover the answers.

Understanding the universe requires curiosity and systematic study. We must embrace the scientific method, which involves making observations, forming hypotheses, and conducting experiments to test our theories. This approach allows us to peel back the layers of the unknown, gradually revealing the intricate workings of the cosmos. Through science, we can comprehend the forces that shape the stars, the planets, and the very fabric of reality itself.

In essence, science is our guiding light in the vast darkness of the unknown, enabling us to explore and understand the universe’s profound mysteries. Through diligent study and relentless curiosity, we can unlock the secrets of existence, continually pushing the boundaries of what we know and expanding our understanding of the cosmos.

I know that I am standing on a surface that appears flat but is, in fact, round. This sphere, our Earth, has a metallic core and is enveloped by a fuzzy atmosphere. It is surrounded by a magnetic field that protects us from the constant barrage of subatomic particles from the sun, which is 150 million kilometers away and the strongest source of light, reaching our planet in just eight minutes. This light also illuminates the days of other planets, comets, and asteroids in the main asteroid belt and the Kuiper Belt, which can be considered the outer boundary of our solar system, extending through the Oort Cloud into interstellar space filled with gas clouds and dust lanes. We locate ourselves on one of the outer arms of the Milky Way Galaxy, which has a supermassive black hole at its center. There are millions of such galaxies drifting away from each other due to the expansion of our universe, a phenomenon explained by dark matter and dark energy.

This is what we have learned after decades of intensive research in the field of astronomy. However, it is not just astronomy alone that has provided this information. Astronomy is the study of celestial bodies, their positions, and phenomena such as eclipses and the phases of the moon. It is like an advanced version of stargazing. Observing planets is part of astronomy. But, if we send rovers to a planet, is that still astronomy? We have sent Curiosity to Mars, Juno to Jupiter, and Cassini to Saturn. Curiosity is conducting geology, metallurgy, chemistry, image processing, and almost everything except traditional astronomy. Thus, according to the modern definition, astronomy encompasses everything observed and experimented on beyond Earth’s atmosphere.

Now, you might ask why it is so important to study this field of science. Astronomy has led to revolutions in almost every field. Let’s go back in time, even before telescopes were invented. What did people see then? They clearly knew they lived in a place that seemed stationary while the sky appeared to move. They saw the sun rising and setting, so geocentrism seemed perfectly correct at that time. However, over time, people learned that the sun is the center of the solar system.

The invention of the telescope marked a significant milestone. Galileo and Newton made significant improvements to it. Newton also developed calculus and Newtonian mechanics to understand the behavior of moving planets. As a result, our knowledge of mathematics, physics, and chemistry improved. Then came another revolution: photography. We could capture much fainter objects on photographic plates. Today, we use computers to analyze images taken by telescopes. Over time, astronomy has opened doors to many more branches of study, which aren’t strictly astronomy but are closely connected.

Many people are unaware that Astronomy, Astrophysics, and Cosmology are three distinct but closely related branches of science. Astronomy is the study of celestial bodies, their positions, and their motions in space. Astrophysics, on the other hand, applies principles and laws of physics, chemistry, and mathematics to understand the nature and behavior of these bodies. For instance, Astronomy tells us about the existence of a star system called Trappist-1, approximately 40 light-years away. Astrophysics, however, informs us that the planets in this system have solid surfaces and may be tidally locked to their star, meaning the same side of the planet always faces the star, resulting in perpetual day on one side and perpetual night on the other. This could lead to weather patterns vastly different from those on Earth, such as strong winds blowing from the day side to the night side and extreme temperature changes.

Cosmology is the study of the universe as a whole. It encompasses topics like the Big Bang, dark energy, and the cosmic microwave background. Cosmology relies more on logic and reasoning than on direct observation and analysis. It seeks to understand the large-scale properties of the universe and its origins, structure, evolution, and ultimate fate.

About a century ago astrology was also a science. Astrologists looked into the night sky to predict the positions of planets and expressed how they affected our lives. What we do not realize is that the night sky is changing. The position of our earth in the milky way is not where it was a hundred years ago. The constellations are changing. Thus in today’s date astrology is more like a pseudo science.

It’s not just scientists who enjoy the pleasure of studying astronomy; everyone can become an amateur astronomer with some basic knowledge. We are all born scientists, and curiosity is a fundamental part of being human. Astronomy encompasses several categories: simulation/computation, observation, theoretical physics, and experimental physics. Theoretical physics involves applying laws and equations to prove new theories and is notoriously challenging. Experimental physics often requires large and expensive apparatus. However, observation is something everyone can engage in!

Take William Herschel, for example. A classically trained musician, he became an amateur astronomer who discovered Uranus and was the first to observe binary star systems. With a good amateur telescope, you can observe changes in the sky and report your findings to an astronomical society. Significant discoveries can earn you recognition. Thomas Bopp and Carolyn Shoemaker are notable amateurs who made significant contributions, discovering 32 comets, 377 minor planets, and 800 asteroids!

For those without a telescope, many citizen science organizations allow you to analyze their data using your computer. NASA frequently offers opportunities for public participation. For instance, the JunoCam project invites everyone to analyze and process images taken by the Juno probe.

Astronomy is an accessible and exciting field for anyone with a curious mind. Whether through direct observation with a telescope or participating in citizen science projects, everyone has the potential to contribute to our understanding of the universe.