First Results: Unveiling the Depths of Space
The James Webb Space Telescope (JWST), a marvel of modern space observation, was launched into orbit around the L2 Lagrange point on January 24. This cutting-edge telescope has the unparalleled ability to explore the farthest reaches of space, providing a glimpse into the light of the first stars and galaxies that emerged shortly after the Big Bang.
On July 12, NASA released the first series of JWST images, capturing the deepest and clearest views ever seen in the history of space observation. Among these images was the awe-inspiring “Webb’s First Deep Field,” showcasing the galaxy cluster SMACS 0723. The President of the United States, Joe Biden, had the privilege of viewing this extraordinary photograph at the White House.
The head of NASA, Bill Nelson, expressed great satisfaction, noting that the picture covered merely a minuscule fraction of the vast starry sky, represented by a mere grain of sand held at arm’s length.
Peering into the Depths of Centuries: Unraveling Cosmic History
The age of our universe is estimated to be approximately 13.8 billion years. The previous space telescope, “Hubble,” provided a glimpse into the past, reaching back 13.3 billion years and capturing images of space objects formed 500 million years after the Big Bang. This period, known as the epoch of reionization, witnessed the formation of the first galaxies, as gravity condensed gas within them, giving birth to the first stars and essential elements like carbon and oxygen.
With JWST, astronomers anticipate an even deeper voyage, aiming to explore the “Dark Ages” that span from 380,550 to 250 million years after the Big Bang. This era was characterized by the universe being predominantly filled with hydrogen and helium atoms, with most of the hydrogen eventually reionizing into protons and electrons, allowing light to traverse the cosmos. This milestone event, known as the cosmic dawn, occurred around 150 million years after the Big Bang.
Due to the universe’s expansion, light from the most distant galaxies reaches us in the form of infrared radiation, stretching beyond the visible spectrum. JWST, exclusively equipped to observe in the infrared range, contains specialized cameras that can penetrate the inner regions of galaxies concealed by cosmic dust. This opens the door to studying the earliest stages of star formation within newly formed galaxies.
A New Perspective on Distance: The Farthest Reaches of the Universe
Traditionally, the most distant astronomical object was believed to be the galaxy GN-z11 in the Ursa Major constellation, discovered by the Hubble telescope in 2016. Its light originated 400 million years after the Big Bang and traveled to us for an astounding 13.4 billion years. However, as the universe continues to expand, the distance to GN-z11 in light years has now reached an astonishing 32 billion.
Since April, JWST’s data has led to multiple updates to the “most distant objects” table. The galaxy CEERS-93316, detected in July, stole the top spot. Born just 250 million years after the Big Bang, it holds the record for the most distant galaxy ever observed.
In the realm of stars, the title of the most distant goes to WHL0137-LS, affectionately named Earendel after one of Tolkien’s characters. It formed around 900 million years after the Big Bang, and its light traveled 12.9 billion years to reach Earth. Initially discovered by the Hubble telescope using gravitational lensing, JWST provided a clearer view of this distant star and its parent galaxy, WHL0137-zD1, now unofficially dubbed the “Sunrise Arch” due to its curved light, resembling a crescent moon.
Challenging Cosmological Theories: Galaxies and the Big Bang
The initial images from JWST have already challenged the generally accepted cosmological theory of the Big Bang. According to this theory, as we move further back in time and space, the number of space objects and their complexity should decrease. However, JWST’s first images revealed a remarkably consistent density of galaxies in the farthest reaches of space, comparable to what we see in our immediate vicinity. Thousands of galaxies were already in existence during the universe’s early stages, with many displaying complex structures, indicating a longer period of evolution.
Astronomers propose that galaxies began forming much earlier, approximately between 120 and 220 million years after the Big Bang, and the first stars made of hydrogen and helium could have emerged within 100 million years.
Rebecca Bowler, an astronomer from the University of Manchester and one of the authors involved in the discovery of CEERS-93316, emphasized that these findings raised significant questions about the formation of the first stars and galaxies, exceeding the predictions of computer simulations.
With only the initial JWST dataset processed so far, it is highly likely that the period of the first space objects’ formation will be pushed even further back, further challenging the Big Bang theory.
Looking Ahead: A Cosmic Journey of Discovery
NASA plans to release new images from JWST to the public on a weekly basis. Scientists eagerly anticipate analyzing these images to unravel the mysteries of the cosmos. Their objectives include determining when the first galaxies emerged, their sizes, compositions, the formation of supermassive black holes, and potential connections between the distribution of galaxies, black holes, and the structure of dark matter. Ultimately, the journey might culminate in creating a comprehensive map of the universe’s overall structure—a testament to humanity’s unyielding quest for knowledge and understanding in the vastness of space.