Its later target is located in the distant spiral galaxy, which helps to map the region of dark matter. The analysis of HST images even helped scientists win the Nobel Prize of 20 1 1 year-finding that the expansion of the universe is accelerating.
So people evaluate HST in this way: when there is a problem on the earth, Hubble will answer it.
"Ten Discoveries" of Science and Technology
In the working time after HST, astronomical observation has achieved great success, and a large number of observation, analysis and research papers have been published in the field of astronomy, with high citation rate.
HST has taken many photos of space, galaxies and stars. Long-term observation of the universe in different bands; The primitive galaxy, which is 0/300 million light-years away from the Earth/Kloc, was observed, and the light emitted came from the early universe just formed after the Big Bang. Five planets in the solar system were discovered.
In addition, outstanding achievements have been made in the observation and research of black holes, quasars, the birth and death of stars, the age of the universe and dark matter.
By 2006, HST had been in orbit for 15 years, made many exciting discoveries and took 4.5 billion beautiful astronomical photos. People magazine summarized its findings and listed the most important "Top Ten Discoveries":
One of the main tasks of HST is to help astronomers determine the exact age of the universe.
Astronomers use HST to observe Cepheid variables in Andromeda and other constellations to determine the expansion rate and age of the universe. HST makes the age of the universe accurate to 65.438+0.3 billion years to 65.438+0.4 billion years. At present, the latest research results make the age of the universe accurate to 65.438+037 billion years.
HST plays an important role in the study of dark energy.
Dark energy is a mysterious force, which acts as a "pedal" for cosmic gas and accelerates the expansion of the universe.
HST's information about supernovae helps researchers reveal that this mysterious force persists in the universe.
HST completed the direct measurement of the atmospheric chemical composition of a planet outside the solar system.
In the atmosphere of a planet the size of Jupiter, it found sodium, hydrogen, carbon and oxygen.
This observation proves that HST and other telescopes can sample chemical components from the atmosphere of some celestial bodies.
HST provides astronomers with photos of distant galaxies, reflecting the scene at the beginning of the birth of the universe and providing valuable information for scientists to further understand the origin and evolution of the universe.
HST photographed M87 elliptical galaxy, and the observation data confirmed that there is a huge black hole in the center of most galaxies.
199965438+1On October 23rd, HST captured the scene of gamma ray burst, which was the largest gamma ray burst recorded at that time.
The images taken show that these brief flashes of radiation come from distant galaxies, which form many stars at a very fast speed.
These images also confirm that these explosions originated from the disintegration of some superstars.
Astronomers use HST to track the "homes" of some quasars (host galaxies) and prove that they are located in the central regions of these galaxies.
HST photographed the protoplanetary disk in Orion Nebula, and the data proved that it was common to bake a disk-shaped dust disk around a young star.
HST captured the scene of1July, 1994, when the comet named Shoemaker Levi-9 broke into 2 1 fragments and hit Jupiter, and the mushroom fireball generated by the impact hit Jupiter.
A group of planetary nebulae with jumping colors photographed by HST depicts the last color of dying stars.
Planetary nebulae are shells of gas thrown by dying stars. Images taken by HST show that planetary nebulae are like snowflakes, and no two are exactly the same.
Great achievements of HST before the second maintenance
By April of 1997, HST had been working for seven years, during which it had achieved fruitful scientific results.
More than 2,000 scientists from more than 20 countries around the world made more than 1 10000 scientific observations by using HST, and wrote 1346 papers based on the analysis.
The main achievements of HST in this period include: enhancing human understanding of the age and size of the universe; It is proved that there are supermassive black holes in the center of some galaxies; Thousands of galaxies and galaxy clusters have been observed, and the "primitive galaxies" in the early days of the birth of the universe have been detected, making it possible for scientists to track and study the development history of the universe; The mysterious quasars and their environment were deeply observed. It reveals the different formation processes of stars more deeply; The composition of heavy elements in the process of star formation in the early days of the universe was studied. The complex composition of the gas shell around the death star is revealed. The dust ring around the young stars in the Orion Nebula was observed, revealing the existence of other planetary systems in the Milky Way. The collision between comet Sumek and Jupiter was observed in detail. Observed planets such as Mars; It is found that there is oxygen in the atmosphere of two moons of Jupiter-Europa and Ganymede.
The near-infrared camera, multi-target spectrometer and image spectrograph installed by HST for the second time enable the telescope to track the ancient galaxies formed about 654.38 billion years after the Big Bang and observe black holes, expanding galaxies, exploding stars and many celestial bodies in detail.
The second maintenance work improved the service life of HST, further enhanced the observation ability, and extended the observation light band to the near infrared range.
Initiate the golden age of early cosmic imaging
In the process of repeated maintenance, HST replaced all the original observation instruments.
Among them, two new instruments are very important, namely the Advanced Sky Survey Camera (ACS) installed in the third maintenance and the Wide Field of View Camera No.3 (WFC3) installed in the fifth maintenance.
ACS can travel through the cosmic distance from visible light to infrared light, which is very suitable for measuring redshift galaxies and medium-large galaxy clusters.
WFC3 is used to observe and study galaxies at all stages of evolution, from very distant young galaxies to closer star systems, including planetary systems in the solar system and exoplanets.
Its main feature is that it can span the electromagnetic spectrum, from ultraviolet to visible light, and enter the near infrared (NIR) band. Its brand-new high-definition image obtained in infrared light source makes it an important pioneer of Weber telescope.
WFC3' s broad-spectrum "panchromatic" coverage and ACS are excellent supplements. Together, they are considered to have created a new golden age of early universe imaging, provided astronomers with the best observation function at that time, and provided excellent wide-field imaging quality in a wide wavelength range.
Explore the early universe and galaxies
The important achievements of HST in observing the early universe and galaxies can be traced back to the situation in BIGBANG hundreds of millions of years later, which is of great significance for understanding the early universe and early galaxies.
Most of these achievements were taken in the ultra-deep field mode of HST. ACS was the main instrument used in the early stage, and the combination of high ACS and WFC3 was mainly used after 2009.
This observation mode is generally carried out in a small sky area, about one tenth of the diameter of the full moon, and the field of view contains about 5500 galaxies. The brightness of the darkest galaxy is one-tenth that of the human eye, and it is difficult to "see" even with advanced observation instruments. Therefore, the principle of "gravitational lens" is often used to focus and amplify the light emitted by the observation source. In addition, taking such a distant image of the universe often requires many long exposures.
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From September 24th, 2003 to June 65438+1October 65438+June, 2004, HST made 800 exposures to the small area of Celestial Tower near Pisces and Bojiang Tower in Nantian District, with a total exposure time of 1 1.3 days, and finally took a photo.
The smallest and reddest dot in the photo shows about 100 distant galaxies, which may be the farthest galaxy known at that time, and existed 800 million years after the Big Bang.
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In 2009, HST took a farther and deeper image of the universe in near infrared light.
In August of that year, the HUDF09 team used the newly installed WFC3 infrared channel to observe the same day. The shooting process lasted ***4 days, and the total exposure time was 173000 seconds.
The red shift z of the galaxy shown in the photo reaches 8 8.5, which is calculated to be the scene of the Big Bang after 600 million years.
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20 12, 165438+ 10, 16, HST took a very deep field of view in Xiaotian near Ursa major, and obtained a galaxy photo named MACS0647-JD by using the magnifying effect of the gravitational lens produced by the huge galaxy cluster around it.
MACS0647-JD is a very young galaxy, which only emits light with red wavelength. It is estimated that it was formed 420 million years after the Big Bang, and its diameter is about 600 light years, which is about 250 times smaller than that of the Milky Way (150000 light years).
Early galaxies are generally extremely unstable, and there will be countless collisions in the next few billion years, and then gradually form a huge cosmic structure that we can see.
In the next/kloc-0.3 billion years, MACS0647-JD may fuse with other galaxies and galaxy fragments for dozens, hundreds or even thousands of times. This observation will help scientists understand how the universe was formed when the first stars and galaxies appeared.
There is no farthest, only farther!
The discoveries made by HST and another important infrared astronomical satellite of NASA (abbreviated as SST) alone or together constantly rewrite the history of observing the farthest galaxy.
It is the sentence "No farthest, only farther!" "
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In May and September of 20 15, two farthest galaxy candidates were discovered. The former is named EGS-zs8- 1 galaxy, which is about 13 1 100 million light years away from the Earth. The latter is named EGS8p7 galaxy, which is about 65.438+032 billion light years away from the Earth.
According to the current estimate of the age of the universe, they were born 600 million years and 500 million years after the Big Bang.
The red shift of EGS-zs8- 1 galaxy is the highest in previous measurements. It was first recognized by HST and SST, and then observed in detail by the 10 meter telescope of Keck Observatory in Hawaii.
According to these observations and analysis results, the researchers believe that the stars in EGS-zs8- 1 are "between 1 billion and 300 million years old", which are very young stars and the first stars after the birth of the universe. Therefore, EGS-zs8- 1 is considered as one of the oldest galaxies observed so far.
The observation results also show that EGS-zs8- 1 is very active, and the speed of star formation is 80 times faster than that of the Milky Way.
In addition, according to the unique colors observed by SST in this galaxy and other early galaxies, scientists believe that it may be caused by the rapid formation of massive young stars due to the interaction of primitive gases in these galaxies.
Further study of this galaxy may reveal the types and quantities of heavy elements formed in early galaxies and young stars.
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In 20 18, HST was very lucky to discover the SPT-clj0615-JD galaxy cluster.
This is a very small embryonic galaxy, only 500 million years away from the Big Bang. HST took photos of this galaxy with the help of gravitational lens principle.
Astronomers estimate that the mass of this small galaxy does not exceed 3 billion solar masses (about1100 of the mass of the Milky Way), and its diameter is less than 2,500 light years, only half that of the small Magellanic Cloud. This galaxy is considered to be the prototype of the young galaxy that appeared shortly after BIGBANG.
Although some other primitive galaxies have been seen in the early days, they all look like little red dot because of their small size and long distance.
However, under the gravitational field of a huge foreground galaxy cluster, not only the light emitted by the background galaxy is amplified, but also the target galaxy is amplified into a small arc (about 2 arc seconds long).
Combined with the data of HST and SST, the red shift value of this newborn galaxy is as high as 10, and its time can be traced back to13.3 billion years ago, that is, 400-500 million years after the birth of the universe.
Scientists pointed out that this galaxy is already at the limit of HST detection ability, and the follow-up work will be continued by the Weber Space Telescope, including the details of the birth and evolution of stars in the early universe and the substructure of early galaxies.
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20 14+65438+20041From October 5 to September 28, HST observed a very distant galaxy in the southern sky, and named it Tayna, WFC3 means "primary".
This observation and imaging also uses the principle of gravitational lens, which greatly enhances the brightness of galaxies and makes them look 20 times higher than normal brightness.
According to its redshift data, scientists estimate that it is about 65.438+0.33 billion years away from us, equivalent to 400 million years after the birth of the universe, and it is the farthest celestial body discovered at that time.
It is about the same size as the Large Magellanic Cloud, and the star formation speed is 10 times that of the Large Magellanic Cloud.
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On February 1 1, 2065438+3, 2005, HST made an in-depth observation of the northern sky, and found the farthest galaxy in the direction of Ursa Major on March 3, 20 16, but the red shift of the galaxy was not estimated at that time.
From April 2065438 to April 2007, an international team led by Jiang of Peking University Institute of Astronomy and Astrophysics used one of the most advanced ground-based infrared telescopes in the world-Keck telescope with a diameter of 10 meter on the Hawaiian Mountain to observe the depth spectrum of the galaxy. Based on spectral analysis and calculation, it is found that the exact redshift of this galaxy is 10957, and it is confirmed as134 billion.
Because the red shift of the galaxy is as high as 1 1, it is named GN-z 1 1, where z stands for red shift.
The research team not only read the accurate red shift from the spectrum, but also read other information.
The spectrum shows that there are three emission lines, which are emitted by carbon and oxygen secondary ionized gas, indicating that the galaxy is rich in non-hydrogen and non-helium elements. This information implies that the newly discovered galaxy may not be the first generation galaxy in the universe.
This discovery is of great significance for understanding the formation of galaxies and stars in the early universe and opens a window for studying very early celestial bodies in the universe.
The joint imaging of HST and SST shows that GN-z 1 1 is 25 times smaller than that of the Milky Way, and the star mass is only 1% of that of the Milky Way. However, the growth rate of GN-z 1 1 is very fast, and the speed of star formation is about 20 times that of the Milky Way.
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Scientists are very excited about the observation and achievements of HST and SST in the very deep early universe.
The Weber telescope with wider infrared band and higher instrument observation accuracy should be able to observe the early universe and the first stars and galaxies farther away from the Big Bang, which are only hundreds of millions of years old, and it is possible to achieve more breakthrough results.