2 – Universe Through the Eyes of Hubble
Once seeing Universe Through the Eyes of Hubble; it has snapped over 1.1 Million Bedazzling images of the cosmos since its launch. From nearby stars and nebulae to galaxies at the very distant edge of the observable universe. Its deep camera technology allows us to look ever deeper into space revealing a much younger universe that has been constantly changing and evolving.
Measuring Distances through Time
Most of these galaxies are gathered in large clusters and Super-clusters which all connect to form a 3D path across intergalactic space known as the cosmic web. When we talk about space most of the time we are referring to the observable universe or the known universe. A spherical geocentric region of space that is comprised of all the galaxies and Mata that can be detected from earth.
Light emissions have had enough time to reach the solar system since they were emitted light travels at just under 300 000 kilometers per second. That is extremely fast, the fastest speed attainable in the universe in fact. But even just beyond our galaxy there is a light delay which impairs our ability to see the universe as it appears now. That’s why it helps to use light years as a unit of measurement.
Hubble Space Telescope
The further away a galaxy is, the longer the light travel time and the younger the galaxy appears to be. The deeper we look, the further back we are looking in time. Through the different stages of the universe’s life nothing has allowed us to look deeper into this rich history than the magnificent Hubble Space Telescope.
The Hubble Telescope is a bust-sized satellite which launched in 1990. It orbits the earth and faces out towards space allowing it to image the universe undeterred by atmospheric disturbances which hamper ground-based telescopes. It has a number of different instruments and filters and has received numerous upgrades throughout the years; which have kept it at the forefront of human technology.
Hubble has snapped over 1.1 Million Bedazzling images of the cosmos since its launch. From nearby stars and nebulae to galaxies at the very distant edge of the observable universe. Its deep camera technology allows us to look ever deeper into space revealing a much younger universe that has been constantly changing and evolving.
Hubble Deep Field
Nothing captures this evolution quite like the Hubble Deep Field. The Hubble Deep Field image is one of the most important images ever. It was taken in 1995 after Hubble received a servicing upgrade two years earlier. It dramatically broadened the telescope’s ability to see the most distant galaxies.
Around One-Tenth of the Hubble Telescope’s Operational Time is allocated to high-ranking staff and physicists wishing to study unexpected phenomena. Then director of the Space Telescope Science Institute Robert Williams devoted his time slot to imaging extremely faint and distant galaxies as a means to test our theories on the age and size of the universe.
Looking into the Dark
Unlike most of the images captured by Hubble which usually have a luminous target; the deep field image was created by focusing the telescope’s instruments on a tiny seemingly empty patch of the night sky where nothing can be seen from the earth. In order for this to work the telescope needed an area with a high enough galactic latitude that the field would not be obscured by the light from the Milky Way’s core.
Thus a small area was chosen in the constellation of Ursa Major also known as the Big Dipper or The Plow. The Point chosen by Williams was tiny an area roughly one twelfth of the diameter of the moon in the sky equivalent to a mere 124 millionth of the total night sky expanse over some 10 days. The telescope gathered light from the area and 342 photographs were taken using a variety of the telescope’s filters.
The data was then processed and the image was compiled revealing a majestic view of the universe’s history contained within this tiny pin-sized segment of the sky are over 3000 Galaxies at an array of distances including some of the oldest and most distant that had been discovered.
Seeing the Galactic Birth
At the time this image isn’t so much a representation of distance in the universe rather it is a window back through time in the shallower field. We can see rich spiral galaxies. The further back we travel the less luminous and structured the galaxies become. Most of the very distant galaxies in the image occupy only a few pixels and shine much less brightly because these early galaxies not had much time for vigorous star formation. Instead had lots of early star forming gases.
The presence of many unstructured irregular galaxies in the early universe reaffirms our belief that after The Big Bang; Mata began building from the ground up. First atoms then stars then clusters of stars then Turret Dwarf Galaxies. After billions of years of star birth and death and countless galactic collisions rich spiral galaxies like the ones we see here began to form.
Compound galaxies bursting with luminous stars. If we were able to see the most distant recesses of the deep field as it is today; then we would probably see large spiral and elliptical galaxies like we do in our surrounding space. But again light just gives us that special opportunity to stare backwards through time in the following year.
A Follow-Up Deep-Filled Image was taken to ensure that the original was truly representative of the distant universe. The results of the Hubble Deep Field South Image were much the same. This time even capturing the light from a Quasar in the early universe after another servicing mission to Hubble in 2002. The telescope was able to take even deeper images still.
Changing the Glasses for History
In 2004 they snapped the Hubble Ultra Deep Field; the deepest photograph of the universe ever taken from the Constellation of Fornax. This image reaches the limit of what is possible to observe through visible light in space. To see any further back we need to use infrared radiation. A 2009 servicing mission to Hubble, equipped it with new Sensitive Infrared Detecting Instruments.
Hubble re-snapped all three deep fields in infrared. This time revealing thousands more primordial galaxies and several of the most distant ever to be observed. Astrophysicists probably won’t get a better picture than this until the James Webb Telescope finally launches.
The Inflating but NOT Expanding Universe
Edwin Hubble and his accompanying legacy have had a profound impact on modern day astronomy. Of his discoveries one sticks out from the rest underpinning everything that we observe and have spoken about today cosmic expansion. The discovery that the universe itself is expanding.
This came about after Hubble surveyed 24 newly discovered nearby galaxies and had established a linear relationship between the radial velocity of the galaxies and their distance from earth. Simply putting galaxies outside of our local galactic group; all appear to be moving away from us. The further away they are the faster they appear to be receding.
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