The Hubble Space Telescope: Our Window to the Universe

Telescopes here on the ground are wonderful tools for studying our planets and the stars in the universe, to include the history and the future of said universe. There are many varieties of telescopes and all have their places both in the laboratory as well as the everyman’s backyard. But, did you know there is a telescope orbiting Earth right now? Why on Earth would we have telescope orbiting Earth?

Terrestrial based telescopes are plagued by atmospheric interference as well as light and radio frequency background noise (in the case of a radio telescope). As light travels through the atmosphere, for example, it is distorted by bending and scattering the light in random directions. Therefore, if a telescope can be launched into space, it will return images and readings from radio instruments that are much clearer than those which are obtained on the ground.

As you can see form the above photo, titled “The Pillars of Creation”, some astounding astrophotography was made possible because of the Hubble Space Telescope. In the above case, these pillars of gaseous material were photographed about 6,500 to 7,000 light years away. That means that the light that is entering your eye, were you to look at this object now from Earth, traveled 6,500 years to get there. You’d be looking at something, live, as it was 6,500 to 7,000 years ago. That nebula might look nothing like that right now, if you were somehow able to teleport a few thousand miles away from it and observe the nebula; to see what this nebula looks like at this very minute in 2019 from Earth, one would have to wait another 6,500 to 7,000 years to see what it actually looked like in 2019.

Hubble was launched in 1990 by NASA. It is equipped with several instruments, including a “cosmic origins spectrograph”, fine guidance sensors, wide field camera, advanced camera for surveys, near infrared camera and multi object spectrometer.

The above image is the “horsehead nebula”, located in the constellation Orion. The image looks spectacular in part because it is imaged with an infrared light sensor which allows light invisible to the naked eye to be viewed within the visible light spectrum. This means that the nebula’s inner regions can be better seen in greater detail than would otherwise be the case. You may be familiar with infrared emissions if you have ever used a radiative heater; stand in front of the heater in the path of the radiant heat and you will feel warm, but you are cold again as soon as you step out of the direct path of the heater. Although the heat from stars, in this example from the Horsehead Nebula, cannot be felt as such by the human body 1,500 light years away in Earth orbit, the infrared emissions can still be imaged as above.

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The Hubble Telescope was named after Edwin Hubble, who proved that there were other galaxies within the universe and that the universe was expanding. Hubble’s successful launch brought to fruition an idea that was first published in 1946 by Lyman Spitzer who first published a paper on space telescopes…a decade before NASA would become NASA. Above is Edwin Hubble’s photo, and more can be read about him in the acknowledgements section below.

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The Hubble telescope was originally planned on operating for 15 years, putting its original expected retirement date somewhere around 2005. The telescope is still operating, but will not go on forever, and will eventually be succeeded by the James Webb telescope which will be orbited in the near future. The above photo is what the Hubble Telescope looks like in all its orbital glory above Earth’s atmosphere. The James Webb telescope will primarily operate outside of low-earth orbit much farther away from Earth than does Hubble. Although Hubble can view objects in the infrared spectrum, it is primarily used to view in the visible and ultraviolet spectrum. The James Webb telescope will primarily be used to observe in the infrared spectrum. A link provided below goes into more detail about the differences between these two scopes and how/where the James Webb telescope will be situated in orbit.

A nice video that NASA has provided does a good job at demonstrating how viewing various wavelengths of light spectra contribute to a more complete understanding of a celestial object being viewed:

The original question in this post, asking the reader if they knew there was a telescope in Earth’s orbit, is a bit misleading. Yes, there is a telescope orbiting the earth…in fact, there is more than one! Beginning in 1966, the first orbital observatories were put into orbit, some more successful than others. These early models were mostly put in orbit to observe objects in the ultraviolet spectrum and later other spectra not visible to the naked eye and were more primitive than Hubble would be with newer technology. In 2003, the Spitzer telescope, Hubble’s lesser-known sibling, was launched. Originally planned on operating for 2.5 years, Spitzer is still in operation today. There are three “NuStar” mission telescopes in orbit now, there is the Chandra telescope, the European Space Agency’s “XMM” (x-ray mission)...all of which can be learned more about under “acknowledgements”.

Space telescopes have been contributing to our knowledge of the universe for over 50 years now and will continue to do so now and in the future. If you’re interested in using the Hubble Space Telescope, you can apply to use it, but beware: the competition is fierce!

Acknowledgements:

Why do we put telescopes in space?

https://www.quickanddirtytips.com/education/science/why-do-we-put-telescopes-in-space

For more information about Hubble Space Telescope’s instruments:

http://www.ball.com/aerospace/programs/hubble-space-telescope

How light is affected by the atmosphere:

http://history.amazingspace.org/resources/explorations/groundup/lesson/basics/g18a/

Download high-resolution photos of the Horsehead Nebula here:

https://www.spacetelescope.org/images/heic1307a/

Hubble Space Telescope’s Timeline:

https://www.nasa.gov/content/goddard/hubble-timeline-full-text

Edwin Hubble: