The image shown above, the Pearly Blue Dot, is an iconic photo of Earth taken by NASA’s Voyager 1 spacecraft on February 14, 1990. Voyager 1 was hurtling rapidly out of the solar system – beyond Neptune, about 3.7 billion miles (6 billion kilometers) from the sun.
The image, known as the Pearly Blue Dot, shows Earth within a scattered beam of sunlight. Voyager 1 was so far away that – from its perspective – Earth was just a dot of light about the size of a pixel.

The famous astronomer Carl Sagan, after seeing the picture above, said, Look back at that point. There it is, that is home, that is ours, and on it everyone you love, everyone you know, everyone you have ever heard of, every human being who has ever lived, has lived their lives. The sum total of our joys and sorrows, thousands of self-confident religions, ideologies, economic theories, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and farmer, every young couple in love, every mother and father, every hopeful child, inventor and explorer, every teacher of morality, every corrupt politician, every superstar , every supreme leader, every saint and sinner in the history of our species, has lived there – on a speck of dust caught in a sunbeam.

In the past, it was widely accepted that the Earth occupied the central  position in the universe. This notion was eventually supplanted by the Sun,  which is now recognized as the nucleus of the solar system. Our solar  system is nestled within the Milky Way galaxy, which is estimated to  harbor around 400 billion stars. The Sun is orbited by eight planets,  including Earth, along with their moons. At the core of the Milky Way  lies a black hole.

If one could travel at light speed from Earth to the center of the Milky Way,  the journey would take an astonishing 26,000 years. The speed of light in a vacuum is exactly 300,000 kilometers per second. The exact center of the  universe remains a mystery. Approximately 13.8 billion years ago, the  universe began to expand explosively from an infinitely dense and hot point,  an event known as the Big Bang. This expansion continues at the speed of  light. Approximately 2 trillion galaxies (2,000,000,000,000) have been  identified so far, but many more await discovery.

The image above shows thousands of galaxies packed into this near-infrared image of the galaxy cluster SMACS 0723. The finely detailed image is a combination of high-resolution imaging from NASA’s James Webb Space Telescope and a natural effect known as gravitational lensing.

The Big Bang

The Big Bang stands as the prevailing explanation for the origin of the  universe. About 13.8 billion years ago, the universe initiated its rapid  expansion from a region of extreme density and temperature. This  event spurred a rapid expansion of the universe, cooling it  in the process. In the initial moments following the Big Bang, the universe’s  rapid expansion resulted in the formation of the first elementary particles,  such as protons, neutrons, and electrons. Roughly 380,000 years later, as  the universe cooled further, the first atoms formed, principally hydrogen  and helium.

Millions of years after the Big Bang event, hydrogen and helium gases  began fusing under gravity’s influence, giving rise to the first stars. As  gas particles clustered together due to gravitational pull, their pressure  and temperature increased, triggering nuclear fusion. The stars formed  during this period were immense but had brief life spans. In their final  stages, these stars culminated in spectacular ‘supernovae’, dispersing  heavier elements like carbon, oxygen, and iron into the cosmos. The stars  that illuminate our sky today and the planets that orbit them emerged  from the remnants of these colossal explosions. Our solar system formed  around 4.6 billion years ago, starting with the Sun, followed by the  planets and their moons.

Earth

Our Earth took shape approximately 4.5 billion years ago. Initially, it was  a molten rock mass, but as it gradually cooled, a solid crust began to form alongside the development of an early atmosphere. The presence of water  became crucial for life’s emergence on Earth. Life is believed to have  originated in aquatic environments. About 3.5 billion years ago, amino  acids formed, leading to the emergence of single celled organisms  such as amoebas. Eventually, multicellular life forms developed, and the  complexity of living organisms increased. Aquatic creatures moved  onto land, gradually evolving into terrestrial organisms. This evolutionary  process resulted in an extraordinary diversification of life.

The universe is immensely vast. Scientists estimate there are around  2 trillion galaxies within it, each containing roughly 100 billion stars. The  Milky Way, our home galaxy, is merely one of these countless galaxies. The  universe’s expansion is occurring at a pace exceeding the speed of light.  As discovered by Edwin Hubble in the 1920s, galaxies are receding from  one another, attributed to the influence of dark energy.

Modern telescopes, such as the Hubble and James Webb Space Telescopes,  as well as others, serve to investigate the universe. Utilizing these  instruments, scientists capture images of the cosmos by detecting light  emitted billions of years ago, enhancing our understanding of the universe’s  formative stages. Evidence supporting the Big Bang theory is gathered  by analyzing the remnants of the universe’s early radiation, known as  cosmic microwave background radiation.

While the universe remains shrouded in mystery, fresh discoveries are  unveiled daily. One certainty is that life exists beyond Earth. The absence  of aliens visiting us may stem from our lack of advanced technology. We are  not solitary in the cosmos. Perhaps a multiverse exists, as many speculate.