Space is truly the last frontier. For centuries, man has been fascinated by the grandeur of space. From ancient civilisations using primitive instruments for measuring a star’s alignment and distance up to the last century where man has truly made great leaps in exploring outer space.
As of June 2015, The Voyager 1 probe is still travelling through space in its 38th year of operation and still communicates with Earth. Voyager 1 is about 19.5 billion kilometres from earth. It’s the furthest spacecraft from Earth and it’s now officially the only spacecraft to have ever left the solar system. Voyager 1 crossed the region known as heliopause in 2012 and is now considered to be truly in interstellar space.
The Hubble Space Telescope is looking at early galaxies being born right after the Big Bang. This is truly fascinating and shows how important the Hubble Telescope is.
What is the Hubble Space Telescope?
The Hubble Space Telescope is an upgradeable, space-based telescope flying 600 kilometres above most of the image-distorting atmosphere. It is designed to take high-resolution photos and images and accurate spectra by concentrating starlight to form sharper images than possible from the ground, where the atmospheric twinkling of the stars limits the clarity of the images.
Despite its relatively modest size of 2.4 metres, Hubble is more than able to compete with ground-based telescopes that are much larger. Another huge advantage is its ability to observe near-infrared and ultraviolet light, which is otherwise filtered by the atmosphere before it can reach ground-based telescopes.
Hubble was launched into low Earth orbit in 1990 and remains in operation. Although Hubble was not the first space telescope, it is one of the most versatile and the largest. It’s also known as both a vital research tool and a PR boon for astronomy.
The telescope is named after the astronomer Edwin Hubble and one of NASA’s great observatories. It has a 2.4-metre mirror and has 4 main instruments that observe near ultraviolet, visible and near-infrared spectra. Hubble has recorded some of the most detailed visible-light images ever that allowed a deep view of space and time.
The Hubble Space Telescope was built by the US space agency NASA and with contributions from the European Space Agency. The Goddard Space Flight Center controls the HST and The Space Telescope Science Institute selects the targets and processes the data gathered.
The HST was designed to operate for 15 years, but thanks to upgrades and servicing, the telescope is still doing pretty well. Between 1993 and 2009, NASA has sent five space shuttle missions to the space telescope to have it repaired, upgraded and install new scientific instruments. The space telescope has revolutionised human’s understanding of the universe and its history.
Since its launch on April 24, 1990, about 4,000 astronomers from the around the world have used it to produce more than 12,7000 scientific papers, making it one of the most productive instruments ever built.
Precursors to Hubble Space Telescope
The history of HST can be traced back to 1946 where astronomer Klyman Spitzer’s paper “Astronomical Advantages of an Extraterrestrial Observatory”. The paper discussed main advantages of space-based observatory would have over ground-based telescopes. Spritzer devoted his career pushing the development of a space telescope. In 1962, the US National Academy of Sciences recommended the creation and development of a space telescope as part of the US Space program.
Fast forward to the 70s, by 1978 the US Congress approved by the funding of $US 36 million and was aiming for launch in 1983. By 1983, the telescope was named after Edwin Hubble, who made one of the greatest scientific breakthroughs of the 20th century when he discovered that the universe is expanding.
The Flawed Mirror and The Jokes After That
Within weeks of the launch of HST, the images that were captured and returned showed a serious problem with the optical system. The first images appeared clear and sharp as compared to ground-based telescopes, but Hubble failed to achieve a final sharp focus and the best image quality captured was lower than expected.
Image analysis showed that the cause of the problem was the primary mirror has been polished into the wrong shape. Although the mirror was sharp enough to permit high-resolution observations of bright objects, the loss of light and out of focus halo severely reduced the HST usefulness for faint objects of high-contrasts imaging.
It also meant that most of the cosmological programs were impossible since it required the observation of very faint objects. And because of this problem, NASA and Hubble became the punchline of many jokes and regarded HST as a white elephant.
Still, during the first 3 years of Hubble, before the optical corrections, it carried out a big number of productive observations of less demanding targets. The first servicing mission was carried out in 1993 and since then, Hubble began to produce astonishing, iconic and historical images for which it is known now.
To Infinity and Beyond
Not long after the fix on the HST, the Comet Shoemaker-Levy 9 slammed into Jupiter. The comet broke into 20 pieces and plundered the Jupiter and showed the massive earth-sized explosions and plumes after. The images offered insights into the role of comets that may have played in delivering water and other material to solar system’s planets, including the planet Earth.
Hubble also captured images that revealed the bright and dark regions on the surface of the dwarf planet Ceres. Ceres is the largest object in the main asteroid belt between Mars and Jupiter. HST also studied the geology of the asteroid Vesta, which Dawn orbited from July 2011 up to September 2012.
Hubble also pointed its vision at planet Pluto. It helped astronomers in making maps of the planet’s surface. It also helped discover 4 new Pluto moons. The New Horizons have reached Pluto’s orbit and has provided stunning and clear photos of the planet. It took 9 years for New Horizons to be close enough to the planet.
With Hubble’s help, astronomers were able to measure the sideways motion of the approaching Andromeda galaxy and determine that the Milky Way and Andromeda will merge in approximately 4 billion years.
Hubble also helped in surveying galaxies that existed when the universe was just 600 million years old. Previous estimates suggested that the universe was at least 2 billion years old but the Hubble’s images have helped scientist to determine the age of the universe at 13.7 billion years old.
Hubble also proved that black holes exist and even showed supermassive black holes, which weigh in at millions or billions of times the mass of the sun. It also showed that it exists at the centre of most, if not, all galaxies.
Hubble has also helped scientist to better understand the supernovas. One fine example is the captured images of SN1987 A, a supernova that exploded 3 years before the telescope was launched into space.
Hubble has also helped in finding exoplanets before the Kepler spacecraft. In 2008, Hubble was able to capture the first photo of a planet in orbit around another star called Fomalhaut b. HST has also helped in finding 16 potential planets orbiting other stars by monitoring the dips in starlight as each planet passed between its star and Earth.
One of the most significant contributions of Hubble is peering through the past and how the universe may have evolved in time. The Hubble Deep Fields gave astronomers the first and a very clear look back to the time when galaxies were forming. The Hubble Deep Field North and South gave astronomers a good look top the ancient universe and caused a real revolution in modern astronomy.
Deep field observations are long –lasting observations of a specific region of the sky that is intended to reveal faint objects by collecting the light from them for an appropriately long time. The longer the exposure time, the fainter are the objects that will be visible in the images. By using the different deep fields, astronomers were able to study young galaxies in the early universe and the most distant primeval galaxies ever observed.
In a few years, the Hubble will be replaced by the James Webb Space Telescope. Webb is scheduled to launch in October 2018. Until then, Hubble will be doing its great job of exploring the Universe and beyond. It paved the way in knowing what lies ahead and we are just but a very small speck in the vastness of the universe.