At the edge of the galaxy
The most distant space objects are located so far from the Earth that even light years are a ridiculously small measure of their remoteness. For example, the closest cosmic body to us - the Moon is located only 1.28 light seconds from us. How can one imagine the distances that a light pulse cannot overcome in hundreds of thousands of years? There is an opinion that it is incorrect to measure such a colossal space with classical quantities, on the other hand, we have no others.
The most distant star of our Galaxy is located in the direction of the constellation Libra and is removed from the Earth at a distance that light can overcome in 400 thousand years. It is clear that this star is located near the boundary line, in the so-called zone of the galactic halo. After all, the distance to this star is approximately 4 times the diameter of the imaginary expanses of our Galaxy. (Diameter Milky Way estimated at about 100,000 light years.)
beyond the galaxy
It is surprising that the most distant, quite bright star discovered only in our time, although it was observed earlier. For incomprehensible reasons, astronomers did not pay attention special attention on a faintly luminous spot in the starry sky and different on a photographic plate. What happens? People see a star for a quarter of a century and ... do not notice it. More recently, American astronomers from the Lowell Observatory discovered another of the most distant stars in the peripheral limits of our Galaxy.
This star, already dimmed from "old age", can be searched in the sky in the constellation of Virgo, at a distance of about 160 thousand light years. Such discoveries in the dark (in the literal and figurative sense of the word) parts of the Milky Way make it possible to make important adjustments in determining the true values of the mass and size of our star system in the direction of their significant increase.
However, even the most distant stars in our galaxy are relatively close. The most distant quasars known to science are more than 30 times further away.
A quasar (English quasar - short for QUASi stellAR radio source - "quasi-stellar radio source") is a class of extragalactic objects that are distinguished by very high luminosity and such a small angular size that for several years after discovery they could not be distinguished from "point sources" - stars.
Not so long ago, American astronomers discovered three quasars, which are among the "oldest" objects in the universe known to science. Their distance from our planet is more than 13 billion light years. Distances to distant space formations are determined using the so-called "red shift" - a shift in the emission spectrum of fast moving objects. The farther they are from the Earth, the faster, in accordance with modern cosmological theories, they move away from our planet. The previous distance record was set in 2001. The redshift of the then discovered quasar was estimated at 6.28. The current trinity has offsets of 6.4, 6.2 and 6.1.
dark past
Open quasars are only 5 percent "younger" than the Universe. What was before them, immediately after big bang- it is difficult to fix: hydrogen, formed 300,000 years after the explosion, blocks the radiation of the earliest space objects. Only an increase in the number of stars and the subsequent ionization of hydrogen clouds allows us to break the veil over our "dark past".
To obtain and verify such information, it is required teamwork several powerful telescopes. The key role in this matter belongs to the Hubble Space Telescope and the Sloan Digital Telescope, located at the New Mexico Observatory.
The science
Newly opened celestial object is fighting for the title of the most distant observable space object in the universe from us, astronomers said. This object is a galaxy MACS0647-JD, which is located 13.3 billion light years from Earth.
The universe itself, according to scientists, is 13.7 billion years old, so the light from this galaxy that we can see today is its light from the very beginning of the formation of the cosmos.
Scientists observe object with NASA space telescopes Hubble And "Spitzer", as well as these observations were made possible with the help of a natural cosmic "magnifying lens". This lens is actually a huge cluster of galaxies, whose combined gravity warps space-time, producing the so-called gravitational lens. When light from a distant galaxy passes through such a lens on its way to Earth, it is amplified.
Here's what a gravitational lens looks like:
“Lenses like this can magnify the light of an object so much that no human-made telescope can do it., - speaks Marc Postman, an astronomer at the Space Telescope Science Institute in Baltimore. - Without such a magnification, one must make a titanic effort to see such a distant galaxy."
The new distant galaxy is very small, much smaller than our Milky Way. scientists said. This object, judging by the light that has come down to us, is very young, it came to us from an era when the Universe itself was at the earliest stage of its development. She was only 420 million years old, which is 3 percent of her current age.
A small galaxy is only 600 light years wide, but as you know, the Milky Way is much larger - 150 thousand light years wide. Astronomers believe that MACS0647-JD eventually merged with other small galaxies to form a larger one.
Cosmic merger of galaxies
"This object is possibly one of the many building blocks of some larger galaxy, the researchers say. - Over the next 13 billion years, it could go through tens, hundreds or even thousands of mergers with other galaxies or their fragments."
Astronomers continue to observe even more distant objects as their observing techniques and instruments improve. The previous object that held the title of the most distant observable galaxy was the galaxy SXDF-NB1006-2, which is located at a distance of 12.91 billion light years from Earth. This object was seen with telescopes Subaru And "Kek" in Hawaii.
Damn big place. When we look at the night sky, almost everything that is visible to the naked eye is part of our galaxy: a star, a cluster of stars, a nebula. Behind the stars of the Milky Way, for example, the Triangulum galaxy peeps through. We find these "island worlds" everywhere in the universe, wherever we look, even in the darkest and most empty patches of space, if we can only gather enough light to look deep enough.
Most of these galaxies are so far away that even a photon traveling at the speed of light would take millions or billions of years to traverse intergalactic space. Once it was emitted from the surface of a distant star, and now it has finally reached us. And although the speed of 299,792,458 meters per second seems incredible, the fact that we have only traveled 13.8 billion years since the Big Bang means that the distance that light has traveled is still finite.
You probably think that the most distant galaxy from us should be no further than 13.8 billion light years from us, but that would be a mistake. You see, in addition to the fact that light moves at a finite speed through the universe, there is another, less obvious fact: the fabric of the universe itself expands over time.
Solutions general theory relativity, which ruled out such a possibility altogether, appeared in 1920, but the observations that came later - and showed that the distance between galaxies is increasing - allowed us not only to confirm the expansion of the universe, but even to measure the rate of expansion and how it changed over time. The galaxies we see today were much farther away from us when they first emitted the light we receive today.
The EGS8p7 galaxy currently holds the record for remoteness. With a measured redshift of 8.63, our reconstruction of the universe tells us that the light from this galaxy took 13.24 billion years to reach us. A little more math and we'll find that we're seeing this object when the universe was only 573 million years old, just 4% of its current age.
But because the universe has been expanding all this time, this galaxy is not 13.24 billion light-years away; in fact, it is already 30.35 billion light years away. And do not forget: if we could instantly send a signal from this galaxy to us, it would cover a distance of 30.35 billion light years. But if you instead send a photon from this galaxy towards us, thanks to dark energy and the expansion of the fabric of space, it will never reach us. This galaxy is already gone. The only reason The reason we can observe it with the Keck and Hubble telescopes is that the light-blocking neutral gas in the direction of this galaxy turned out to be quite rare.
Hubble mirror compared to James Webb mirror
But don't think that this galaxy is the most distant of the most distant galaxies we'll ever see. We see galaxies at such a distance as far as our equipment and the Universe allow us: the less neutral gas, the larger and brighter the galaxy, the more sensitive our instrument, the farther we see. In a few years, the James Webb Space Telescope, because it will be able to capture light of a longer wavelength (and therefore with a large redshift), will be able to see light that is not blocked by neutral gas, will be able to see dimmer galaxies than our modern telescopes (Hubble, Spitzer, Keck).
In theory, the very first galaxies should appear with a redshift of 15-20.
We will talk specifically about the most distant discovered star, since space objects (galaxies, quasars, gamma-ray bursts) that are even further away have already been found.
So, the most distant star from Earth is a supernova with the code name GRB 090429B.
The abbreviation GRB stands for gamma-ray burst (a large-scale burst of energy accompanied by light flashes recorded by special telescopes). Telescopes filmed the explosion of this supernova on April 29, 2009. This supernova became, apparently, the most distant star from the Earth. According to calculations, it arose 520 million years after the Big Bang.
Big Bang (Big Bang)- a cosmological model of the universe, according to which the Universe began to expand rapidly from a singular point, which has an infinitely small (zero) size. In other words, this theory claims that we originated from nowhere and are flying to nowhere. However, this topic is for a completely different article.
A gamma-ray burst from the farthest star from Earth was observed by telescopes: Swift, Gemini North, the Very Large Telescope, the UK Infrared Telescope, Hubble and the La Silla Observatory telescope.
Light from GRB 090429B reached Mother Earth only 13.140 billion years after the outburst. GRB 090429B should be a massive star, probably 30 times the mass of the Sun.
The universe is a damn big place. When we look at the night sky, almost everything that is visible to the naked eye is part of our galaxy: a star, a cluster of stars, a nebula. Behind the stars of the Milky Way, for example, the Triangulum galaxy peeps through. We find these "island worlds" everywhere in the universe, wherever we look, even in the darkest and most empty patches of space, if we can only gather enough light to look deep enough.
Most of these galaxies are so far away that even a photon traveling at the speed of light would take millions or billions of years to traverse intergalactic space. Once it was emitted from the surface of a distant star, and now it has finally reached us. And although the speed of 299,792,458 meters per second seems incredible, the fact that we have only traveled 13.8 billion years since the Big Bang means that the distance that light has traveled is still finite.
You probably think that the most distant galaxy from us should be no further than 13.8 billion light years from us, but that would be a mistake. You see, in addition to the fact that light moves at a finite speed through the universe, there is another, less obvious fact: the fabric of the universe itself expands over time.
Solutions to general relativity that ruled out such a possibility altogether appeared in 1920, but the observations that came later - and showed that the distance between galaxies was increasing - allowed us not only to confirm the expansion of the Universe, but even to measure the rate of expansion and how it changed over time. The galaxies we see today were much farther away from us when they first emitted the light we receive today.
The EGS8p7 galaxy currently holds the record for remoteness. With a measured redshift of 8.63, our reconstruction of the universe tells us that the light from this galaxy took 13.24 billion years to reach us. A little more math and we'll find that we're seeing this object when the universe was only 573 million years old, just 4% of its current age.
But because the universe has been expanding all this time, this galaxy is not 13.24 billion light-years away; in fact, it is already 30.35 billion light years away. And do not forget: if we could instantly send a signal from this galaxy to us, it would cover a distance of 30.35 billion light years. But if you instead send a photon from this galaxy towards us, thanks to dark energy and the expansion of the fabric of space, it will never reach us. This galaxy is already gone. The only reason we can see it with the Keck and Hubble telescopes is that light-blocking neutral gas in the direction of this galaxy turned out to be quite rare.
Hubble mirror compared to James Webb mirror
But don't think that this galaxy is the most distant of the most distant galaxies we'll ever see. We see galaxies at such a distance as far as our equipment and the Universe allow us: the less neutral gas, the larger and brighter the galaxy, the more sensitive our instrument, the farther we see. In a few years, the James Webb Space Telescope will be able to look even further, because it will be able to capture light of a greater wavelength (and therefore with a large redshift), it will be able to see light that is not blocked by neutral gas, it will be able to see dimmer galaxies than our modern telescopes (Hubble, Spitzer, Keck).
In theory, the very first galaxies should appear with a redshift of 15-20.