In July 1923, the Oldenburg publishing house in Munich published the book “Rocket into Outer Space.” Its author was Hermann Julius Oberth, who became famous decades later and was even promoted to the “founding fathers” of rocketry. The main provisions of his work can be briefly formulated as follows:
1. With the current state of science and technology, it is possible to create an apparatus capable of going beyond the Earth’s atmosphere.
2. In the future, such devices will be able to develop such a speed that they will overcome gravity and go into interplanetary space.
3. It is possible to create devices that can perform similar tasks with a person on board, and without serious damage to his health.
4. Under certain conditions, the creation of such devices may become quite feasible. Such conditions may arise in the coming decades.
In the final, ascertaining phrases of the last part of the book, there is a discussion of distant prospects - the possibility of seeing the far side of the Moon, launching artificial Earth satellites, their widespread use for various purposes, creating orbital stations, carrying out certain types of activities with their help, including scientific research and astronomical observations. This allows us to consider July 1923 as the “starting point” of space astronomy.
To commemorate the 90th anniversary of this event, the editors of our journal have prepared a series of articles about ongoing (or recently completed) projects to explore the Universe, based on astronomical instruments beyond the Earth's atmosphere. The complete chronicle of this most interesting and actively developing branch of astronomy deserves a separate book, which, undoubtedly, will be written soon.
Visible space telescopes
In the course of evolution, the human eye has acquired the greatest sensitivity to that part of the electromagnetic spectrum that is best transmitted by the earth's atmosphere. Therefore, astronomical observations since ancient times have been carried out mainly in the visible range. However, already at the end of the 19th century, it became clear to astronomers that the “ocean of air” with its inhomogeneities and unpredictable currents created too many obstacles for the further development of observational technology. If, when measuring the positions of stars in the sky, all these errors were mainly eliminated by statistical methods, then attempts to obtain high-resolution images of celestial bodies were unsuccessful even in places with the best astroclimate. When observing from the Earth's surface, the most advanced telescopes could provide a standard resolution of about half an arcsecond, in ideal cases up to a quarter of a second. Theoretical calculations showed that moving the telescope outside the atmosphere would improve its capabilities by an order of magnitude (in the ultraviolet part of the spectrum it was possible to achieve almost 20 times higher resolution).
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CHARACTERISTICS OF THE SPACE VEHICLE:
> Length - 13.3 m, diameter - 4.3 m, weight - 11 tons (with installed instruments - about 12.5 tons); two solar panels measure 2.6 x 7.1 m. INSTRUMENTS THAT WORKED OR ARE WORKING AT THE HUBBLE OBSERVATORY: > Wide Field and Planetary Camera. Equipped with a set of 48 light filters to highlight areas of the spectrum that are of particular interest for astrophysical observations. The cameras contain 8 CCD matrices (2 sections of 4 matrices each). A wide-angle camera has a larger viewing angle, while a planetary camera has a larger equivalent focal length, allowing for greater magnifications. It is with this camera that all the stunning “landscape” photographs were taken. |
| SPACE TELESCOPE |
The beginning of the practical implementation of the ideas of extra-atmospheric astronomy is associated with the name of the American astrophysicist Lyman Spitzer. In 1946, he prepared for the Douglas Aircraft Company's RAND (Research and Development) project an extensive report, “The Astronomical Advantages of an Extraterrestrial Observatory,” in which he not only proved that large orbital telescopes would immeasurably expand the capabilities of studying celestial objects, but also outlined a detailed program of such research. The first orbital observatory (to photograph the Sun) was launched by the UK in 1962 as part of the Ariel program.
In 1968, the US National Aerospace Administration (NASA) approved a plan for the construction of a reflecting telescope with a mirror diameter of 3 m. The project received the code name LST (Large Space Telescope). The launch was planned for 1972. But the struggle now continued in the financial “plane”: funds were then allocated, then the next government and Congress reduced funding, until the program was completely curtailed. The diameter of the telescope lens was reduced to 2.4 m, but a new participant in the project appeared - the European Space Agency (ESA), which agreed “in exchange” for 15% of the observation time to partially finance the program and participate in the manufacture of individual instruments.
In 1979, the NASA report “Strategy for Space Astronomy and Astrophysics for the 1980s” was published, which proposed the implementation of the “Large Observatories” program. Already funded by Congress in 1978, the LST became one of the four elements of the project - it was assigned the role of “observer” in the visible, as well as near-infrared and ultraviolet ranges. The Compton Observatory (CGRO) was responsible for research in the hard X-ray and gamma-ray range,2 the Chandra telescope (CHO) was supposed to study soft X-rays, and the Spitzer (SST) - the mid- and far-infrared region of the spectrum.
Hubble Space Telescope
Work on the creation of LST moved most quickly. Initially, its launch into orbit was planned for 1983. However, it was not possible to launch it then, but it was decided to name the orbital observatory after Edwin Hubble. On April 24, 1990, the Discovery shuttle launched the telescope into its intended orbit. From the beginning of design to launch, $2.5 billion was spent on this project - with an initial budget of $400 million.
Hubble is currently the oldest and most prolific astronomical instrument operating outside the atmosphere. To keep it in working order, NASA organized 4 repair missions, the last of which was carried out by the crew of the Atlantis shuttle in May 2009. The total cost of operating the orbital observatory on the American side amounted to more than 6 billion dollars; another 593 million euros were allocated by the ESA.
Flight control, data reception and primary processing are carried out by the Goddard Space Flight Center. Within 24 hours, the data is transferred to the Space Telescope Science Institute (STScI), which is responsible for its main processing and publication for use by the scientific community. The Hubble telescope operates as an international research laboratory. Projects from all over the world are considered, although competition for observation time is fierce, so on average one in 10 projects is implemented.
Scientific achievements of the Hubble telescope. Despite the fact that after the start of work, deviations in the shape of the telescope’s main mirror from the calculated ones were discovered (which did not allow it to be used “at full strength”), Hubble almost immediately began to produce valuable scientific results. When creating this instrument, it was stated that its main task was “to direct your gaze into the depths of the Universe.” He had, first of all, to work off the “advance payment” - to continue the research begun by his “godfather” Edwin Hubble: to clarify the constant and verify the law of his name, to confirm the interpretation of the red shift as the Doppler effect and the reality of the expansion of the Universe. The now legendary space telescope successfully completed these tasks.
Astronomers have long ceased to need evidence that our Galaxy is not the only such system in the Universe. There is also no doubt that all these “stellar islands” (more precisely, their gravitationally bound groups) are constantly moving away from each other. The speed of mutual removal is directly proportional to the distance between objects, and the proportionality coefficient is called the “Hubble constant” (H0). Its first estimates, made by Hubble itself, gave a value of about five hundred kilometers per second per megaparsec. Over the next 90 years, they were repeatedly revised, being the subject of heated debate: after all, in fact, this constant, reduced to system units, is the reciprocal - neither more nor less - of the age of the Universe. Its last, most accurate value is 70.4 (km/s)/Mpc (H0 = 2.28x10 -18 s -1), and measurements made by the Hubble telescope made a significant contribution to its establishment. This is precisely what is considered to be his main “scientific feat”.
Having established the fact of the expansion of the Universe, Edwin Hubble limited himself to this, but his “cosmic namesake” went further and managed not only to confirm this at a new technical level, but also to prove the unevenness of this expansion (more precisely, its acceleration). Such a discovery required measurements of the spectral characteristics of objects at extremely large distances - and only Hubble was “strong” in this. It was possible to make several thousand estimates of the brightness of type 1a supernovae, the peculiarity of which is that at the maximum of the outburst they release approximately the same amount of energy, which means that the observed brightness of the outburst depends only on the distance to its source.6 More than a dozen people participated in this research program ground and space telescopes. The fruits of such cooperation were very successful, and the degree of importance of the results obtained for science was sufficient to award the Nobel Prize in physics to the team of authors of the discovery.
To test the “range” of the telescope, several so-called deep surveys of the Universe were carried out. To do this, a site in the sky was selected where there were no nearby galaxies and stars of our Galaxy, and photography was carried out with the longest possible exposures. At the same time, it was possible to capture very distant objects of various types, sizes, luminosities and ages. Among them were young star clusters that are just preparing to become “familiar” galaxies, and already fully formed star systems. Deep surveys of the Universe - the Hubble Deep Field (HDF), jokingly called by astronomers “Deep Punctures of the Universe” - are a look through billions of years into the ancient history of our world.
During one of the “punctures”, Hubble focused its attention on an area the size of one thirty-millionth of the celestial sphere and discovered more than 3,000 dim—at the limit of visibility—galaxies there. A detailed photograph of another similar area of the sky showed the same picture, from which it was concluded that the Universe is isotropic - its homogeneity in all directions on large scales. Since such observations require very long exposures (during one of the sessions the “exposure” reached 11.3 days), they were rare. Astronomers were able to see protogalaxies - the first clumps of matter that formed less than a billion years after the Big Bang and later merged into modern star systems.
Of particular note is the unique Great Observatories Origins Deep Survey (GOODS) experiment, carried out by the coordinated efforts of the Hubble, Spitzer, Chandra space telescopes, the XMM-Newton orbital X-ray telescope and a number of the largest ground-based instruments. The objects of observation were two sites from the Hubble Deep Field program. At redshift Z=6, a spatial resolution of the order of a kiloparsec has been achieved, and photometric redshifts have been determined for 60 thousand galaxies in the field. Participants in this project claim that they looked 13 billion years ago, into the era of reionization, when the radiation of the first stars caused the decay of some interstellar hydrogen atoms into electrons and protons.
The record so far is the “dive” into the depths of the Universe, announced in September 2012 (Hubble extreme Deep Field). For 10 years, a section of the sky in the Fornax constellation was exposed with a total exposure of 2 million seconds. Astronomers claim that in this case they saw the Universe at a completely “childish” age - no more than half a billion years. The dimmest galaxies in the image (there are about 5,500 of them in total) have a brightness 10 billion times lower than the sensitivity limit of human vision.
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ASC FIAN Astrospace Center of the Physical Institute of the Academy of Sciences, Russia ESA European Space Agency NASA National Aerospace Administration, USA CNES National Center for Space Research, France CSA Canadian Space Agency A.S.I. Italian Space Agency JAXA Japan Aerospace Exploration Agency SSC Swedish Space Corporation |
| SPACE TELESCOPE |
| Below the names of the telescopes are the orbital parameters, operator and launch date. |
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For a long time, theoretical astrophysicists tried to convince the scientific community that supermassive black holes must necessarily be present in the central regions of galaxies, but there was no observational evidence of this. As soon as the Hubble telescope “intervened in the dispute,” everything fell into place: now a galaxy without a central black hole is more exotic. Now the scientists’ arguments look very convincing: systematic observations of a large number of stellar systems have revealed a correlation between the size of the bulge (the central condensation of the galaxy) and the mass of superdense objects in their centers, determined from the radial velocities of the stars.
Not all of the space telescope's results required complex long-term observations. Among his photographs there are many that in themselves already represent solved astrophysical problems. He demonstrated the birth of stars in the “Tripartite Nebula” M20 extremely clearly. Planetary nebula NGC 7027 is the final stage of evolution of a star similar to our Sun. The “Pillars of Creation” in the Eagle Nebula have become classic...
At the time of preparing the “flight mission” of the observatory, some problems were not only not a priority, but astronomers only guessed that they would arise. Such tasks, first of all, should include the search for planets of other stars (exoplanets). Thanks to the high sensitivity of its detectors and the absence of the influence of the Earth's atmosphere, Hubble is able to detect an insignificant change in the brightness of the observed star caused by the passage of a planetary-sized satellite in front of its disk. In observational technology, this method of searching for exoplanets is called the “transit method.” It is applicable only for objects whose orbital plane is slightly inclined towards the direction of the Earth, but it allows one to immediately determine many of their characteristics - in particular, size, mass, and sometimes the composition of the atmosphere (by spectral analysis of the star’s radiation during an “eclipse”). A breakthrough discovery should be recognized as the first detection of an organic molecule - methane CH4 - in the gaseous shell of the giant planet HD 189733b using one of the most important instruments of the Hubble telescope - the NICMOS spectrometer (Near Infrared Camera and Multi-Object Spectrometer), installed on board the observatory seven years after launch during the second repair mission.
In addition to planet-like bodies, the space telescope confirmed the existence of numerous protoplanetary disks in star-forming regions (the Eagle Nebula, the Great Orion Nebula) and near some stars. These discoveries initiated the emergence of a very promising scientific direction - the search and study of exocomets and exoasteroid belts. It is now obvious that the process of planet formation in our Galaxy occurs constantly. Hubble has collected a lot of evidence for the recently generally accepted conclusion that exoplanets should be a completely ordinary and widespread phenomenon in the Universe.
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| The Hubble Space Telescope gave us a stunning image of the bright ring of star formation surrounding the heart of a barred spiral galaxy, designated NGC 1097. The galaxy is approximately 45 million light-years away and is visible in the southern constellation Fornax. It belongs to the class of Seyfert galaxies; the fact that its main plane is almost perpendicular to the direction towards Earth makes it a particularly tasty object for astronomers. Hidden in the very center of the galaxy, a supermassive black hole (BH) with a mass of about 100 million solar masses is gradually absorbing matter from the surrounding space. This matter, falling into a black hole, “spins” into an accretion disk, heats up and begins to emit in a wide range of electromagnetic waves. The contours of the disk are clearly outlined by relatively recently “born” stars, the material for which is the matter of the central bar (bridge) of the galaxy falling onto the BH. These star-forming regions glow brightly due to emission from clouds of ionized hydrogen. The diameter of the ring is about 5 thousand light years, and the spiral arms of NGC 1097 extend tens of thousands of light years beyond. However, there are certain moments in the behavior of this galaxy that sharply distinguish it from the community of similar objects. It has two small companions - the elliptical galaxy NGC 1097A, located at a distance of 42 thousand light years from the center of the “main” star system, and the dwarf galaxy NGC 1097B. Their presence certainly influences the evolution of the unusual cosmic “trio”. There are serious reasons to assert that in the recent (on a cosmic scale) past, the interaction between its members was closer and more active. NGC 1097 is also a unique region for supernova hunters: it has already recorded three high-mass star explosions between 1992 and 2003. In this regard, it deserves special attention and regular monitoring. |
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| SPACE TELESCOPE |
The main “field of activity” of a powerful space telescope, of course, was considered to be deep space exploration. Therefore, when studying our Solar System, its potential was used rather limitedly. But the list of his achievements within its boundaries is also impressive. First of all, it should be noted that, unprecedented in the history of astronomy, the fall of fragments of comet Shoemaker-Levy 9 (D/1993 F2 Shoemaker-Levy 9) onto Jupiter in July 1994. This incident was the first observed collision of two bodies in the Solar System.
The Hubble telescope has finally photographed the surface of Pluto with such resolution that it has become possible to talk about mapping it. In images taken by the space observatory, experts distinguish polar caps, bright moving spots and mysterious lines. Also impressive was the discovery at Pluto, in addition to the already known satellite Charon, of four more small moons - Nix, Hydra, PIV, PV.
When observing the asteroid Vesta (4 Vesta), planetary scientists were struck by the high resolution and clear detail of the surface (of course, one should not compare the images taken a decade and a half ago from a distance of more than 110 million km with those obtained by the Dawn spacecraft in 2011-12 gg., while in orbit around Vesta). After Hubble's 2006 study of 2003 UB313, initially considered the 10th planet in the solar system and later named Eris (136199 Eris), the celestial body was deemed too small to be considered a planet. There is no doubt about the importance of the discovery of polar (auroral) lights on the giant planets Jupiter and Saturn, as well as on the Jovian moons Io and Ganymede.
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| An important object of research for the Hubble telescope has become planetary nebulae - the post-mortem stage of the evolution of stars like our Sun. As thermonuclear fuel reserves are depleted, they begin to periodically eject their matter into the surrounding space, turning into the state of a white dwarf - a super-dense object that releases energy due to slow gravitational compression. The ejected shells, illuminated by the radiation of the stellar remnant, form complex structures in which the dynamics of the process of emission of matter can be seen. A striking example of such structures are the gaseous filaments of the nebula NGC 5189, located in the southern constellation Muca at a distance of 1800 light years (it has the unofficial name “Spiral”). It can be assumed that the nebula was formed through the interaction of two independent expanding structures inclined towards each other. Such double bipolar structuring is usually explained by the presence of a massive satellite in the “burnt out” star, which, with its attraction, influences the direction of the “rivers” of outflowing gas. Although this explanation is very plausible, it was not possible to visually detect such a companion in this case. The bright golden rings consist of a large number of radial filaments and comet-like nodes. They are usually formed by the combined effects of ionizing radiation and stellar wind. The photograph was taken on July 6, 2012 with a Wide Field Camera 3 through narrow-band filters centered on the main emission lines of ionized sulfur, hydrogen and oxygen atoms. Broadband filters were used to determine the star's color in the visible and near-infrared. |
| SPACE TELESCOPE |
Since service missions to the Hubble Observatory are no longer possible (due to the cessation of flights of American reusable spacecraft), its technical capabilities will only decrease over time, and its equipment will become obsolete. NASA guarantees full operation of the telescope until at least 2015. Its proposed “replacement”, named after the former director of the US space agency James Webb (James Webb Space Telescope - JWST), will be focused mainly on the near-infrared range. This is due to the fact that as a result of the development of adaptive optics technology, which compensates for the influence of atmospheric inhomogeneities, ground-based observatories will soon be able to take photographs of celestial objects with “Hubble” resolution, spending much less money and effort than is required for launching into orbit and operating a tool of comparable size.
Space observatories play a major role in the development of astronomy. The greatest scientific achievements of recent decades rely on knowledge gained from spacecraft.
A large amount of information about celestial bodies does not reach the earth because... it is hampered by the atmosphere we breathe. Most of the infrared and ultraviolet range, as well as X-rays and gamma rays of cosmic origin, are inaccessible for observation from the surface of our planet. To study space in these ranges, it is necessary to move the telescope beyond the atmosphere. Research results obtained using space observatories revolutionized man's understanding of the universe.
The first space observatories did not exist in orbit for long, but advances in technology made it possible to create new instruments for exploring the universe. Modern space telescope- a unique complex that has been developed and operated jointly by scientists from many countries for several decades. Observations obtained using many space telescopes are available for free use by scientists and astronomy enthusiasts from all over the world.
Infrared telescopes
Designed for space observations in the infrared range of the spectrum. The disadvantage of these observatories is their heavy weight. In addition to the telescope, a cooler has to be placed into orbit, which should protect the telescope’s IR receiver from background radiation - infrared quanta emitted by the telescope itself. This has resulted in very few infrared telescopes operating in orbit throughout the history of spaceflight.
Hubble Space Telescope
Image by ESO
On April 24, 1990, with the help of the American shuttle Discovery STS-31, the largest near-Earth observatory, the Hubble Space Telescope, weighing more than 12 tons, was launched into orbit. This telescope is the result of a joint project between NASA and the European Space Agency. The Hubble Space Telescope is designed to last for a long time. The data obtained with its help are available on the telescope website for free use by astronomers around the world.
Ultraviolet telescopes
The ozone layer surrounding our atmosphere almost completely absorbs ultraviolet radiation from the Sun and stars, so UV quanta can only be detected outside of it. Astronomers' interest in UV radiation is due to the fact that the most common molecule in the Universe, the hydrogen molecule, emits in this spectral range. The first ultraviolet reflecting telescope with a mirror diameter of 80 cm was launched into orbit in August 1972 on the joint American-European Copernicus satellite.
X-ray telescopes
X-rays bring us information from space about powerful processes associated with the birth of stars. The high energy of X-ray and gamma rays allows them to be recorded one at a time, with an accurate indication of the registration time. Due to the fact that X-ray detectors are relatively easy to manufacture and light in weight, X-ray telescopes have been installed on many orbital stations and even interplanetary spacecraft. In total, more than a hundred such instruments have been in space.
Gamma-ray telescopes
Gamma radiation is similar in nature to x-ray radiation. To record gamma rays, methods similar to those used for X-ray studies are used. Therefore, space telescopes often examine both X-rays and gamma rays simultaneously. Gamma radiation received by these telescopes brings us information about the processes occurring inside atomic nuclei, as well as about the transformations of elementary particles in space.
Electromagnetic spectrum studied in astrophysics
| Wavelengths | Spectrum area | Passing through the earth's atmosphere | Radiation receivers | Research methods |
| <=0,01 нм | Gamma radiation | Strong absorption |
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| 0.01-10 nm | X-ray radiation | Strong absorption O, N2, O2, O3 and other air molecules |
Photon counters, ionization chambers, photoemulsions, phosphors | Mainly extra-atmospheric (space rockets, artificial satellites) |
| 10-310 nm | Far ultraviolet | Strong absorption O, N2, O2, O3 and other air molecules |
Extra-atmospheric | |
| 310-390 nm | Near ultraviolet | Weak absorption | Photomultipliers, photoemulsions | From the surface of the Earth |
| 390-760 nm | Visible radiation | Weak absorption | Eye, photoemulsions, photocathodes, semiconductor devices | From the surface of the Earth |
| 0.76-15 microns | Infrared radiation | Frequent absorption bands of H2O, CO2, etc. | Partially from the surface of the Earth | |
| 15 µm - 1 mm | Infrared radiation | Strong molecular absorption | Bolometers, thermocouples, photoresistors, special photocathodes and photoemulsions | From balloons |
| > 1 mm | Radio waves | Radiation with wavelengths of about 1 mm, 4.5 mm, 8 mm and from 1 cm to 20 m is transmitted | Radio telescopes | From the surface of the Earth |
Space observatories
| Agency, country | Observatory name | Spectrum area | Launch year |
| CNES & ESA, France, European Union | COROT | Visible radiation | 2006 |
| CSA, Canada | MOST | Visible radiation | 2003 |
| ESA & NASA, European Union, USA | Herschel Space Observatory | Infrared | 2009 |
| ESA, European Union | Darwin Mission | Infrared | 2015 |
| ESA, European Union | Gaia mission | Visible radiation | 2011 |
| ESA, European Union | International Gamma Ray Astrophysics Laboratory (INTEGRAL) |
Gamma radiation, X-ray | 2002 |
| ESA, European Union | Planck satellite | Microwave | 2009 |
| ESA, European Union | XMM-Newton | X-ray | 1999 |
| IKI & NASA, Russia, USA | Spectrum-X-Gamma | X-ray | 2010 |
| IKI, Russia | RadioAstron | Radio | 2008 |
| INTA, Spain | Low Energy Gamma Ray Imager (LEGRI) | Gamma radiation | 1997 |
| ISA, INFN, RSA, DLR & SNSB | Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) |
Particle detection | 2006 |
| ISA, Israel | AGILE | X-ray | 2007 |
| ISA, Israel | Astrorivelatore Gamma ad Immagini LEggero (AGILE) |
Gamma radiation | 2007 |
| ISA, Israel | Tel Aviv University Ultraviolet Explorer (TAUVEX) |
Ultraviolet | 2009 |
| ISRO, India | Astrosat | X-ray, Ultraviolet, Visible radiation | 2009 |
| JAXA & NASA, Japan, USA | Suzaku (ASTRO-E2) | X-ray | 2005 |
| KARI, Korea | Korea Advanced Institute of Science and Technology Satellite 4 (Kaistsat 4) |
Ultraviolet | 2003 |
| NASA & DOE, USA | Dark Energy Space Telescope | Visible radiation | |
| NASA, USA | Astromag Free-Flyer | Elementary particles | 2005 |
| NASA, USA | Chandra X-ray Observatory | X-ray | 1999 |
| NASA, USA | Constellation-X Observatory | X-ray | |
| NASA, USA | Cosmic Hot Interstellar Spectrometer (CHIPS) |
Ultraviolet | 2003 |
| NASA, USA | Dark Universe Observatory | X-ray | |
| NASA, USA | Fermi Gamma-ray Space Telescope | Gamma radiation | 2008 |
| NASA, USA | Galaxy Evolution Explorer (GALEX) | Ultraviolet | 2003 |
| NASA, USA | High Energy Transient Explorer 2 (HETE 2) |
Gamma radiation, X-ray | 2000 |
| NASA, USA | Hubble Space Telescope | Ultraviolet, Visible radiation | 1990 |
| NASA, USA | James Webb Space Telescope | Infrared | 2013 |
| NASA, USA | Kepler Mission | Visible radiation | 2009 |
| NASA, USA | Laser Interferometer Space Antenna (LISA) |
Gravitational | 2018 |
| NASA, USA | Nuclear Spectroscopic Telescope Array (NuSTAR) |
X-ray | 2010 |
| NASA, USA | Rossi X-ray Timing Explorer | X-ray | 1995 |
| NASA, USA | SIM Lite Astrometric Observatory | Visible radiation | 2015 |
| NASA, USA | Spitzer Space Telescope | Infrared | 2003 |
| NASA, USA | Submillimeter Wave Astronomy Satellite (SWAS) |
Infrared | 1998 |
| NASA, USA | Swift Gamma Ray Burst Explorer | Gamma radiation, X-ray, Ultraviolet, Visible radiation |
2004 |
| NASA, USA | Terrestrial Planet Finder | Visible radiation, Infrared | |
| NASA, USA | Wide-field Infrared Explorer (WIRE) |
Infrared | 1999 |
| NASA, USA | Wide-field Infrared Survey Explorer (WISE) |
Infrared | 2009 |
| NASA, USA | WMAP | Microwave | 2001 |
What is Hubble?
American scientist Edwin Powell Hubble became widely known for his discovery of the expansion of the Universe. Great scientists still often mention him in their articles. Hubble is the man after whom the radio telescope was named, and thanks to whom all associations and stereotypes were completely replaced.
The Hubble telescope is one of the most famous among objects that are directly related to space. It can be confidently considered a real automatic orbital observatory. This space giant required a considerable financial investment (after all, the costs of an unearthly telescope were hundreds of times higher than the cost of a ground-based telescope), as well as resources and time. Based on this, the two largest agencies in the world, such as NASA and the European Space Agency (ESA), decided to combine their capabilities and make a joint project.
In what year it was launched is no longer secret information. The launch into earth orbit took place on April 24, 1990 on board the Discovery shuttle STS-31. Returning to history, it is worth mentioning that the launch year was originally planned to be different. The expected date was supposed to be October 1986, but in January of the same year, The Challenger disaster occurred and everyone was forced to postpone the planned launch. With each month of downtime, the cost of the program increased by 6 million dollars. After all, it is not so easy to keep an object in perfect condition that will need to be sent into space. Hubble was placed in a special room , in which an artificially purified atmosphere was created, and the on-board systems were partially functioning.During storage, some devices were also replaced with more modern ones.
When Hubble was launched, everyone expected an incredible triumph, but not everything immediately turned out the way they wanted. Scientists encountered problems from the very first images. It was clear that there was a defect in the telescope mirror, and the quality of the images was different from what was expected. It was also not entirely clear how many years would pass from the discovery of the problem to its solution. After all, it was obvious that it was impossible to replace the main mirror of the telescope directly in orbit, and returning it to Earth was extremely expensive, so it was decided that it was necessary to install additional equipment on it and use it to compensate for the mirror defect. So, already in December 1993 The shuttle Endeavor was sent with the necessary structures. The astronauts went into outer space five times and successfully installed the necessary parts on the Hubble telescope.
What new did the telescope see in space? And what discoveries has humanity been able to make based on the photographs? These are some of the most common questions scientists ever ask. Of course, the largest stars captured by the telescope did not go unnoticed. Namely, thanks to the uniqueness of the telescope, astronomers simultaneously identified nine huge stars (in the star cluster R136), whose mass is more than 100 times the mass of the Sun. Stars have also been discovered whose mass exceeds the mass of the Sun by 50 times.
Also notable was the photo of two hundred insanely hot stars that together give us the nebula NGC 604. It was Hubble that was able to capture the fluorescence of the nebula, which was caused by ionized hydrogen.
Speaking about the big bang theory, which today is one of the most widely discussed and most reliable in the history of the origin of the Universe, it is worth remembering the cosmic microwave background radiation. CMB radiation is one of its fundamental evidence. But another one was the cosmological redshift. Taken together, the result was a manifestation of the Doppler effect. According to it, the body sees objects that approach it in blue, and if they move away, they become redder. Thus, observing space objects from the Hubble telescope, the shift was red and on this basis a conclusion was made about the expansion of the Universe.
When looking at telescope images, one of the first things you will see is the Far Field. In the photo you will no longer be able to see the stars individually - they will be entire galaxies. And the question immediately arises: at what distance can the telescope see and what is its extreme boundary? In order to answer how the telescope sees so far, we need to take a closer look at the Hubble design.
Telescope Specifications
- Overall dimensions of the entire satellite: 13.3 m - length, weight about 11 tons, but taking into account all installed instruments, its weight reaches 12.5 tons and diameter - 4.3 m.
- The shape of the orientation accuracy can reach 0.007 arcseconds.
- Two bifacial solar panels are 5 kW, but there are 6 more batteries that have a capacity of 60 amp hours.
- All engines run on hydrazine.
- An antenna that is capable of receiving all data at a speed of 1 kB/s and transmitting at 256/512 kB/s.
- The main mirror, the diameter of which is 2.4 m, as well as the auxiliary one - 0.3 m. The material of the main mirror is fused quartz glass, which is not susceptible to thermal deformation.
- What is the magnification, so is the focal length, namely 56.6 m.
- The frequency of circulation is once every hour and a half.
- The radius of the Hubble sphere is the ratio of the speed of light to the Hubble constant.
- Radiation characteristics - 1050-8000 angstroms.
- But at what height above the Earth’s surface the satellite is located has long been known. This is 560 km.
How does the Hubble telescope work?
The operating principle of the telescope is a reflector of the Ritchie-Chretien system. The structure of the system is the main mirror, which is concave hyperbolically, but its auxiliary mirror is convex hyperbolic. The device installed at the very center of the hyperbolic mirror is called an eyepiece. Field of view is about 4°.
So who actually took part in the creation of this amazing telescope, which, despite its venerable age, continues to delight us with its discoveries?
The history of its creation goes back to the distant seventies of the 20th century. Several companies worked on the most important parts of the telescope, namely the main mirror. After all, the requirements were quite strict, and the result was planned to be ideal. Thus, PerkinElmer wanted to use its machines with new technologies to achieve the desired shape. But Kodak signed a contract that involved using more traditional methods, but for spare parts. Manufacturing work began back in 1979, and polishing of the necessary parts continued until mid-1981. The dates were greatly shifted, and questions arose about the competence of the PerkinElmer company; as a result, the launch of the telescope was postponed to October 1984. Soon, incompetence became increasingly apparent, and the launch date was pushed back several more times. History confirms that one of the projected dates was September 1986, while the total budget for the entire project grew to $1.175 billion.
And finally, information about the most interesting and significant observations of the Hubble telescope:
- Planets have been discovered that are outside the solar system.
- A huge number of protoplanetary disks have been found that are located around the stars of the Orion Nebula.
- There has been a discovery in the study of the surface of Pluto and Eris. The first cards were received.
- Of no small importance is the partial confirmation of the theory about very massive black holes that are located in the centers of galaxies.
- It has been shown that the Milky Way and the Andromeda Nebula are quite similar in shape but have significant differences in their history of origin.
- The exact age of our Universe has been unambiguously established. It is 13.7 billion years old.
- Hypotheses regarding isotropy are also correct.
- In 1998, studies and observations from ground-based telescopes and Hubble were combined, and it was found that dark energy contains ¾ of the total energy density of the Universe.
Space exploration continues...
Man has always been interested in the mysteries of the universe. When did our universe appear? How long ago? Are there other planets similar to Earth? There are a huge number of questions, and astronomers, with the help of their instruments, have always tried to see more, further and more clearly in space.
Observing from the surface of our planet is generally quite convenient. You just need to choose a place with an atmosphere that is not polluted by various emissions. The telescope lens can be made as large as available technology allows. All that remains is to automate the process of observing and recording results. And, it would seem, that’s it, get ready to learn all the secrets of the world. However, researchers face a big problem associated with the absorption of infrared and ultraviolet radiation coming from space by the earth's atmosphere. Meanwhile, this wave range, invisible to the human eye, contains a huge amount of information that helps to understand the essence of the processes taking place.
Lyman Spitzer
The idea of creating an observation device, the image of which is not subject to distortion by the earth's atmosphere, was first put forward by Hermann Oberth in 1923. At that time, such prospects seemed very distant in the future. However, already in 1946, in the work of astrophysicist Lyman Spitzer, the basic principles of the functioning of an extraterrestrial observatory were formulated. It was proposed to use as the main working element not a system of lenses, as in conventional terrestrial telescopes, but a huge mirror that would collect flows of outgoing radiation on its surface. In this case, the accuracy of observation will be affected only by the evenness of the mirror surface without any introduced distortions caused by turbulent flows of the earth’s atmosphere. And of course, such a telescope could operate in all ranges of interest.
The period from the formulation of the idea to its implementation was more than 40 years. After all, first it was necessary to work out in detail the procedure for launching the telescope into low-Earth orbit, and tools that made it possible to polish the surface of the mirror with great precision appeared only in the 60s of the last century.
The American corporation NASA is rightfully considered a pioneer in the field of creating large space telescopes. Since 1962, she has been closely involved in the creation of universal surveillance equipment. The first orbital astronomical observatories (OAO) were quite cumbersome and did not have stable communication channels with the control center for transmitting accumulated information. But even this imperfect technique made it possible to make a number of scientific discoveries. For example, the ultraviolet spectrogram of the Sun was photographed and studied for the first time.
Hubble Telescope
The next step was to develop a telescope with a large mirror that could be used to study distant galaxies and planets. Its construction took about 15 years, and the cost was so high that NASA had to turn to the European Space Agency for help. As a result, it was launched into orbit only in 1990. The telescope was named after the American scientist Edwin Hubble, who developed the concept of the expanding Universe.
The first results of the new space telescope were simply stunning. The previously impossible resolution, which makes it possible to obtain a clear image of distant planets without any distortion, created a real sensation in the scientific community. With the help of Hubble, it was possible to examine in detail the process of the collision of comet Shoemaker-Levy with Jupiter, obtain clear images of the surface of Pluto, and discover previously unknown planets located outside the solar system.
Fragment of the Carina Nebula photographed by the Hubble telescope in 2010
The Hubble Space Telescope ends its lifespan in 2014. It should be replaced by a new device, the construction of which is already in full swing by NASA and the European Space Agency. Russian scientists also participate in the development. It is planned that the new telescope will be named after James Webb, a talented American scientist who made a huge contribution to the study of the theory of the origin of our world.
The diameter of the new telescope's mirror will be 6.5 meters (Hubble's is 2.5 m). To protect it from solar radiation, it is planned to deploy a huge reflective screen, the purpose of which will be to remove excess heat from the measuring sensors. The telescope will be able to look even further into the universe, catching the radiation of the most distant stars. Therefore, it is no coincidence that the main purpose of launching it into orbit is considered to be to conduct a whole set of observations in relation to planetary systems outside our galaxy, study their physicochemical parameters and determine the possibility of the existence of organic life on them. With the help of a new telescope, scientists will aim to prove that we are not alone in the universe.
Space telescopes are typically telescopes that operate outside the Earth's atmosphere and thus do not bother to peer through that atmosphere. The most famous space telescope today is the Hubble Space Telescope, which has discovered hundreds of exoplanets, revealed many spectacular galaxies, cosmic events, and expanded the horizons of our view into space. Hubble will be replaced by the James Webb Space Telescope, which will be launched into space in 2018 and whose mirror will be almost three times the diameter of Hubble's mirror. After James Webb, scientists plan to send the High-Definition Space Telescope (HDST) into space, but this is only in the plans for now. Be that as it may, space telescopes have and will continue to account for the majority of our discoveries in deep space.
We imagine space as a dark, cold and quiet place where there is nothing but the endless Universe around. However, one can argue about the silence of outer space. Thousands of different radio signals travel throughout the Universe. They are emitted by various space objects and most of these signals are nothing more than noise and interference. But among them there are also those that cannot be classified as interference. And recently it registered a huge Chinese radio telescope.
