ARCHIVO | El tamaño del universo conocido: Earendel | El Siglo 21 es Hoy

Earendel, the most distant star ever found, gives us a new figure for the size of the known universe. The Hubble Space Telescope detected the most distant star ever seen, named Earendel, an Old English word meaning ‘morning star’ or ‘rising star’. It is very distant; the light it emitted, which Hubble only saw in 2022, took about 13 billion years to reach us. It is so far away that its light has taken 12.9 billion years to reach Earth. A light-year is a unit of length used to measure astronomical distances, approximately equal to 9.46 × 10¹² km. It is the distance light travels in one Earth year. For the first time, we are seeing the light from such a distant star, from a single star. Because of the distance of its light, scientists are certain that it belongs to the first generation of stars in the history of the Universe. The star is already dead, having exploded billions of years ago. Its light reached the Hubble Space Telescope and human eyes because the light from the galaxy where it was located was distorted by gravitational lensing, creating a physical effect equivalent to the magnification provided by a lens. A Help for Hubble The Hubble Space Telescope, or simply Hubble, is one of the most renowned space telescopes in modern astronomy. It orbits outside Earth's atmosphere in a circular orbit around the planet at 593 kilometers above sea level, with an orbital period of between 96 and 97 minutes. The Hubble telescope is very powerful, but it has a limit to how far away or how far back in time it can see. The greater the distance, the greater the delay in the light's travel. In this case, Hubble's capabilities were aided by the phenomenon of gravitational lensing. In astrophysics, a gravitational lens is formed when light from distant, bright objects like quasars is bent around a massive object located between the emitting and receiving objects. This phenomenon was predicted by Albert Einstein. Einstein had been able to predict the behavior of starlight as it passes near the Sun. He predicted it in 1912, a few years before the publication of his theory of general relativity in 1916. Just as the curved glass of a bottle distorts the image when we look through it, a gravitational lens distorts and magnifies the image of distant galaxies, producing double or multiple images, arcs, etc. And if a lensing galaxy is directly in front of a background galaxy, it produces what is called an "Einstein ring." Light from a source, instead of traveling in a straight line, is deflected or bent by the presence of a massive body, which warps spacetime. It's as if light were attracted by the gravity of a massive body. An Einstein ring is a special case of gravitational lensing of light, caused by the precise alignment of the source, the lens, and the observer. This creates a symmetry around the lens, resulting in a ring-like structure. During a solar eclipse, the astronomer Arthur Eddington observed that light from distant stars bent as it passed near the Sun. Essentially, massive bodies act like lenses, deflecting light from objects coming from behind and magnifying it. It's a natural telescope. Gravitational lensing phenomena can also be used to detect the presence of invisible massive objects, such as black holes. The vast cosmic distances would have made Eärendel's observation impossible without the Hubble Space Telescope and gravitational lensing. The galaxy that hosts the star Earendel has been magnified and distorted by particular gravitational lenses into a long crescent shape also known as the Dawn Arc. Earendel will allow us to learn more about the early universe. Because it formed when the universe was very young, we can learn what stars were like at that time and how they have evolved over time. Farther than Icarus Hubble has made more than 1.5 million observations in its operational life. Before Earendel took the record for the 'most distant star' in the Universe, an equally ancient star held the title. Also discovered by Hubble, 'Icarus' was a blue star whose light took 9 billion years to reach Earth. Yes, the Hubble telescope is over 30 years old; it was launched into orbit in 1990, but it continues to function perfectly. The discovery was published on March 30, 2022, in Nature, and marks a milestone in contemporary astronomical observation. According to the Johns Hopkins University team, Earendel is observable due to the position in which...