The recipe for a space telescope
It’s been a quarter century we have a ‘spy’ in space, which has continued to unveil the stunning secrets hidden within the cosmos. But long before seeing its first light, the space telescope was conceived in the minds of brilliant scientists, who struggled to convince the world about the importance of making it happen.
In the early seventeenth century, when Galileo Galilei made the first astronomical observations with a telescope, nobody imagined instruments have hundreds of kilometers of land area.
The discoveries of Galileo marked a before and after in the conception of the universe, it showed that the Sun was not perfect and had scars on its surface -the Solares spots, there were bodies orbiting other planets -the famous four Galilean moons of Jupiter and even the lunar surface is irregular.
The idea of send a telescope into space for many outlandish, emerged in the twentieth century. It was easy to imagine the technological challenges involved, coupled with the high costs She estimated 2,000 million dollars. At the time there were already huge telescopes on the ground. The American astronomer George Ellery Hale had undertaken the task of building the telescope in the world’s largest land.
On four occasions, he conceived the largest telescope of his time, including one with a main mirror of 5 , 1 meters on Mount Palomar in California (USA), which saw first light 10 years after the death of Hale, in 1948, and was named after the astronomer as a tribute.
In 1923, Hermann Oberth, German physicist, published his book The rocket into interplanetary space, in which he mentioned how a telescope into orbit by a rocket propulsion. It was perhaps the first reference to send a telescope into space, and almost half a century was given before the launch of Hubble in 1990.
But what was the point of sending an instrument in a complex space mission and spend the same money that could be built 20 optical devices such as Palomar?
The main enemy of observational astronomers is the Earth’s atmosphere, a turbulent medium that makes the images lose quality and distorted. The same effect is experienced when a coin is flipped to the bottom of a pool and prevents define the shape of the object under water.
In astronomy, the fluid is air and the bodies that we observe would be the currency that we are not able to see in detail. The stars we see flashing in the sky precisely the effect of our atmosphere.
In 1946, the American astronomer Lyman Spitzer published astronomical advantages of an extraterrestrial observatory, which summarized the importance for astronomy to shake above the terrible effect of the atmosphere.
The space age
was missing almost a decade yet to begin formally the conquest of space, marked by the launching of the first artificial satellite Soviets: Sputnik 1, on October 4, 1957. Thereafter, progress was rapid: in 1958 NASA and the space race was created managed to send the first man into space Yuri Gagarin in 1961 aboard Vostok 1.
62, and probably as a result of events, the National Academy of Sciences of the United States ruled on the desired space telescope. In 1968, NASA gave the green light to the project and suggested that the release was in 1979.
The 70′s brought financial problems, which were partially resolved with the support and incorporation of the European Space Agency the project. Final funds to begin building the telescope were not approved by Congress until 1978, and in 1983, the telescope was named Hubble, named after the astronomer who discovered the expanding universe.
Build it was a long and delicate process, mainly by the primary mirror, 2.4 meters in diameter, with a reflective layer of aluminum thousandth the thickness of a hair. This delayed the project and its release date was then scheduled for late 1986.
When everything was ready, came the crash of the space shuttle Challenger, a minute after its launch on January 28 1986, disintegrated in the air. The space missions were frozen for almost three years. The Hubble remained on the ground waiting for a new date. The day chosen was the April 24, 1990.
The world’s eyes focused that day on the Discovery shuttle, which led him successfully into space.
The expectation to know the first images had a sudden reversal: the Hubble ‘saw’ blurry. Although the images were better than those of terrestrial telescopes, their quality was far from expected. The error was 2.2 microns in the shape of primary mirror. The tension returned and efforts focused on finding solutions.
In its 25 years of operation, the Hubble servicing missions received 5, the first in 1994, which put ‘glasses’ to improve’ vision ‘. The part of victory, with the first images of high quality, was given the January 13, 1994.
The last servicing was in May 2009, battery replacement and installation of a system mechanic to engage the telescope the day you decide I retire him.
The history of the Hubble is undoubtedly an elaborate blend of ingredients, which has one of the most successful recipes in scientific research. Today, after 25 years of tireless work, Hubble does not stop surprising and revealing secrets of the cosmos.
Santiago Vargas Dominguez Special
for TIME
Ph. D., a researcher at the Astronomical Observatory of the National University.
A legacy of images
When looking at the sky at night we would appreciate all the stars and heavenly bodies who accompany us. But clouds covering the sky and light pollution of cities often reduce our chances, because the natural reaction of the pupil occurs. Contract because of light
What if we could be on top clouds? There, the universe would be before our eyes as it is: infinite. It is a privilege that only have today who inhabit the International Space Station.
Since the Earth is only the option of building an apparatus to put in orbit around our planet, equipped with instruments that pretend to be our eyes, and enhance it further. To collect information and send it to anyone connected to the internet to observe.
This device came true and accurate operates 25 years ago by unprecedented cooperation between European space agencies (ESA) and the USA (NASA).
It is called Hubble Space Telescope.It was made by man, without divine intervention, and allowed us to observe in detail planets, moons, asteroids and comets in our neighborhood as well as understanding the evolution of our system Solar. One of historical images that has left us is the collision, in 1994, a comet Shoemaker-Levy 9 with a planet, Jupiter
It has also led us to discover exoplanets planets. – outside our solar system, such as Fomalhaut b, a body in training, 1,700 years ago.
Its orbit is highly elliptical around its star -from same name, located 25 light years from the earth. Beyond detect, has opened up the possibility of understanding the atmospheric composition of these exoplanets and their orbital parameters and allowed us to compare with ours.
Many of the iconic images taken by the Hubble correspond nebulae showing a final stage of stellar life, but also regions where stars are being formed from interstellar gas and dust.
With the help of space telescope we have come to observe, with deep detail, one of the most enigmatic objects in the universe: the supermassive black holes. These are objects with masses up to two billion higher than the Sun, which appear to have a close relationship with the formation and evolution of galaxies.
And that is taken into the darkness of space you have carried appreciate the fainter objects in the universe, either by their remoteness or the dim light they emit.
The Hubble, in turn, is instrumental in the conquest of space. If we travel to an Earth-like planet in another star system, the first step is to identify and then trace the paths that lead to it.
Although it sounds like science fiction, studies of planetary atmospheres, such as that of GJ1214b, three times the radius of Earth (they call Super-Earth), carried find clouds using data from the Hubble. That shows that we are not very far to find a twin planet to ours.
And as these findings bring us to the future, the space telescope, observing deep in the cosmos, has led us to meet our distant past. The image of the Hubble Deep Field, which corresponds to an angular size of a tenth the diameter of the Moon, contains about 10,000 galaxies.
Using data associated with this have been determined that the estimated age the universe is of the order of 13.798 million years. The spectacular not stop there. With Hubble we have observed the dynamics and galactic evolution, as the collision of galaxies stadiums, and agglomeration of these in so-called clusters of galaxies.
And the look in different colors brightness of distant supernovae -stars supermasivas-, we discovered that the universe expanded rapidly, driven by dark energy; We are still trying to understand if indeed it exists or will come across one of the most important mysteries to be discovered throughout this century.
The Hubble not only changed our perception of the universe, but we has allowed an intimate approach with the cosmos, which on Earth feel human when we left the field with people we love.
The Space Telescope took the curtain on the window through which we had always observed the universe, to know the most depth.
Camilo Delgado-Correal
THE TIME Candidate Ph. D. from the University of Ferrara
The promises of Webb
In late 2014, after 116 days in one of the largest vacuum chamber in the world, all the more sophisticated infrared cameras of the world emerged to be integrated into other components of what will be the largest object ever launched into space in one piece: the James Webb Space Telescope. Dubbed by some as the successor to the Hubble, threatened several times by the vagaries of politics and the US budget and resurrected by the stubbornness of astronomers, the James Webb will be the first observatory built by man capable of detecting the light emitted by the first stars that arose in the history of the universe.
To achieve this, must be equipped with a giant mirror (6.5 meters) divided into 18 hexagonal panels that mimic the structure of a honeycomb. To avoid optical problems such as the Hubble in its infancy, align their panels with an accuracy equivalent to a ten-thousandth the thickness of a human hair
Also, being a telescope that observes mainly infrared light. – heat-sensitive, Webb should operate at extreme temperatures of 240 degrees below zero, survive a difficult pitch and then deploy their instruments accurately, at a distance of 1.5 million kilometers from Earth. Just have a chance because, unlike Hubble, no missions astronauts to upgrade or repair
The need for an infrared telescope in space is not a fad. Is the step in the sequence of Galileo findings that began over 400 years ago when he first noted an optical instrument to the stars and let the observed record. The photons that reach us from distant parts of the universe are particles of light mainly of two types: visible light our eyes detect and comes mainly from surfaces of stars, and infrared photons invisible to our eyes. Body temperature emitted photon defines its type. Visible light reports on conditions in the stellar surfaces that gleam thousands of degrees.
The infrared light contains the secrets of colder bodies such as planets, comets and asteroids, ie bodies with solid surfaces and cloudy atmospheres where living conditions conducive expect. So put the Webb space makes sense, because the Hubble, even with his incredible portfolio of discoveries has only reported half the cosmic inventory.
Travel back in time
The data you get the Webb from 2018 will help to understand the evolution of the universe and the origin of life. Compared to its predecessor, see further and further back in time. This will allow to have a look-the first of mankind times as remotos- to when the first galaxies were formed. Also, the moments shining lights of the first stars, ending the dark era of the universe and initiating thermonuclear processes that give rise to the chemical elements of which are shaped living things on Earth. These observations are only possible in infrared, because as the universe has expanded, the original light of these primordial stars, which was visible and ultraviolet to be emitida- has been stretched and now comes in infrared photons. The Webb also will advance the understanding of the formation of stars and planets.
The regions where other solar systems are born hidden behind thick layers of interstellar dust, making them inaccessible to visible light observed Hubble. Penetrate these dark curtains be possible for Webb. Its sophisticated spectrometers will measure the composition of the atmospheres of extrasolar planets tens of leveraging ‘eclipses’ happening these planets passing in front of their stars. Passing through remote uncharted planets skies, light from these stars give clues about the chemistry of other worlds and will reduce our uncertainty about how likely the biology of life elsewhere in the galaxy. Missing a couple of years for the James Webb deploy its petals -the hexagonal beryllium primary mirror panels are made of this material to lighten weight- and were channeled into new paths of discovery. Meanwhile, its components are still coming to NASA, which will be the final tests. In the future, it is possible that Webb and Hubble operate simultaneously. But even if the Hubble is forced to retreat, the new colossus will be ready and will surprise a new generation with the first glare of the universe.
Juan Rafael Martínez Galarza
TIME
> Research at the Harvard-Smithsonian Center for Astrophysics.
No comments:
Post a Comment