Finding what’s out there
Space Week is Oct. 4-10, so here are some of NASA’s latest discoveries and why Edwin Hubble’s history-making photo, taken on this day in 1923, revolutionized astronomy.
This image above is from the NASA/ESA Hubble Space Telescope features the spiral galaxy IC 1954, located 45 million light-years from Earth in the constellation Horologium. NASA posted the image on Sept. 27.
It sports a glowing bar in its core, majestically winding spiral arms, and clouds of dark dust across it. Numerous glowing, pink spots across the disc of the galaxy are H-alpha regions that offer astronomers a view of star-forming nebulae, which are prominent emitters of red, H-alpha light.
Some astronomers theorize that the galaxy’s “bar” is actually an energetic star-forming region that just happens to lie over the galactic center.
For more images go to NASA’s hubblesite.org.
The data featured in this image come from a program that extends the cooperation among multiple observatories: Hubble, the infrared James Webb Space Telescope, and the Atacama Large Millimeter/submillimeter Array, a ground-based radio telescope.
Here are some other images:
You can find NASA’s Hubble telescope gallery here.
The Hubble telescope
The Hubble Space Telescope orbits just above Earth’s atmosphere at an altitude of approximately 320 miles.
When Hubble launched in 1990, it was expected to have a lifespan of about 15 years. Largely because of five successful astronaut servicing missions to the telescope, Hubble’s technology was upgraded and improved, and the telescope remains scientifically productive to this day. All indications are that the telescope will continue operating into the late 2020s and possibly beyond.
Pointing accuracy
In order to take images of distant, faint objects, Hubble must be extremely steady and accurate. The telescope is able to lock onto a target without deviating more than 7/1000th of an arcsecond (an arcsecond is an angular measurement that is 1/3600 of a degree), or about the width of a human hair seen at a distance of 1 mile.
Hubble’s Mirrors
Primary Mirror Diameter: 94.5 inches
Primary Mirror Weight: 1,825 pounds
Secondary Mirror Diameter: 12 inches
Secondary Mirror Weight: 27.4 pounds
Hubble basics
Hubble captures light in many different wavelengths using many cameras and instruments:
Wide Field Camera 3 (WFC3) sees three different kinds of light: near-ultraviolet, visible and near-infrared.
Cosmic Origins Spectrograph (COS) sees exclusively in ultraviolet light.
Advanced Camera for Surveys (ACS) sees visible light.
Space Telescope Imaging Spectrograph (STIS) is a spectrograph that sees ultraviolet, visible and near-infrared light.
Near Infrared Camera and Multi-Object Spectrometer (NICMOS) is Hubble’s heat sensor. It’s sensitive to infrared light and lets scientists look for objects hidden by interstellar dust.
Who was Edwin Hubble?
Born in 1889 in Marshfield, Missouri, he entered the University of Chicago in 1906 as an undergraduate, earning a bachelor’s degree in mathematics and astronomy. He was one of the first Rhodes Scholars at Oxford University, where he studied law. He returned home to study astronomy at the University of Chicago. When the U.S. entered World War I, Hubble finished his dissertation and reported to the army for duty.
He served in France and made the rank of major before the war ended.
In 1919, Hubble joined the Mount Wilson Observatory where the 100-inch Hooker Telescope (the world’s largest at the time) was. Hubble used the telescope to observe faint, cloud-like patches of light broadly labeled nebulae. His observations brought these fuzzy patches into focus, and in the process transformed the field of cosmology.
On Oct. 5, 1923, Hubble trained the Hooker telescope on a hazy patch of sky called the Andromeda Nebula. He found that it contained stars just like the ones in our galaxy, only dimmer. One star he saw was a Cepheid variable, a type of small star with a known, varying brightness that can be used to measure distances. Hubble deduced that the Andromeda Nebula was not a nearby star cluster but rather an entirely other galaxy, now called the Andromeda galaxy.
The most important discovery Hubble made resulted from his study of the spectra of 46 galaxies, and in particular of the Doppler velocities of those galaxies relative to our own Milky Way galaxy. What Hubble found was that the farther apart galaxies are from each other, the faster they move away from each other. Based on this observation, Hubble concluded that the universe expands uniformly. Several scientists had also posed this theory based on Einstein’s General Relativity, but Hubble’s data, published in 1929, helped convince the scientific community.
One of Mount Wilson’s Interferometric Array telescopes in the foreground with the 60-inch telescope in the background on August 3, 2007, which has been instrumental in the modern understanding of the universe. With a total of six telescopes at the top of Mount Wilson, including a 101-inch one and a two solar ones, many people visit the location north of Pasadena yearly, including the likes of Edwin Powell Hubble (1889–1953), Albert Einstein (1879—1955) and most recently theoretical phycisist Stephen W. Hawking (1942-). (SGVN/Staff Photo by Raul Roa/SXCity)
Edwin Hubble transformed our understanding of the universe. He received many scientific honors but did not receive a Nobel Prize because it was not given for astronomy until after he died, and not given posthumously.
After a long career entirely at Mt. Wilson Observatory, he died of a heart attack on Sept. 28, 1953, in San Marino, California.
You can read a more detailed biography here.
Source: NASA, hubblesite.org