Hubble-Distance: Pictured is a scale of just how far space telescopes have been able to see vs. how far Webb (JWST) will detect. This will be the first time in history we will be able to gather data from the first-forming stars and galaxies. Image credit: NASA and Ann Feild.
By Brooke Edwards, NASA/JPL Solar System Ambassador
Humans are moving forward ⸺ into the past. Orbiting our planet for 31 years, the Hubble Space Telescope has provided scientists with enormous amounts of information about our universe. This month, Hubble will see its successor fly past it into space and take images with a much larger mirror and infrared views. The James Webb Space Telescope is scheduled to launch at 7:20 a.m. EST, Dec. 25, on an Ariane 5 rocket, from Arianespace’s ELA launch complex in French Guiana. NASA and the European Space Agency have partnered to make this project possible. Launching Webb into its orbit a million miles from Earth is ESA’s important contribution to the mission.
Hubble’s legacy
Hubble spent decades revealing the secrets of space and time to us, mainly using ultraviolet and optical wavelengths. The telescope has helped us, along with other missions, determine multiple features of our universe: its approximate age, number of galaxies (two trillion and counting) and characteristics of phenomena such as black holes, nebulae and supernovae. Hubble provides images that are beautiful, almost beyond belief. The Earth-orbiting telescope was kept operational thanks to multiple space shuttle service missions. Once the space shuttle stopped flying in 2011, Hubble was left unserviceable. As with all technology, the telescope’s hardware and onboard software is aging, and its days may be numbered.
Webb’s destination
Like a product shipped to its destination in a box, the James Webb Space Telescope is folded into the Ariane 5 rocket’s payload and will be “unboxed” as it reaches its solar orbit, about 30 days after launch. Unlike Hubble, which orbited Earth at an altitude of approximately 340 miles, Webb will orbit the sun at the second Lagrange Point, a million miles from Earth. At this point, the telescope orbits the sun at the same pace as the Earth, keeping both parties lined up and allowing signals to be received 24/7. This is thanks to this L2 orbital range.
In fact, there are five of these points in which two objects can orbit the sun at the same pace. Each of them are named after the 18th century mathematician who first theorized their possibility. Joseph-Louis Lagrange came up with the “Three-body Problem”, in which he theorized how three objects could orbit all in a position relative to each other. One can only imagine what his reaction would be to seeing his work in action today.
Webb contains a sunshield, about the size of a tennis court, in front of the telescope to protect it from the sun’s heat and radiation as well as reflected sunlight from the moon and Earth. This is extremely important as Webb will be detecting infrared light from distant galaxies. With that vast distance, the infrared signals received can be weak, therefore any radiation or light from the sun, moon, or Earth could interfere with data collection. It will also help the Webb stay cool, which is essential for an infrared telescope.
Webb’s objective
It will take about five months after Webb reaches its orbit for all the instruments onboard to be calibrated. About six months after launch, scientists will begin to receive data. The Webb telescope will have 6.25 times the light-collecting area Hubble has, due to its much larger primary mirror. It will mainly collect infrared light, which will be a huge advantage when looking at far-distant objects. As the universe expands, the light from distant stars and galaxies is redshifted from the visible and UV into the infrared. Infrared light is also able to penetrate the universe’s vast clouds of dust and gas which absorb visible light. With infrared imaging, we will soon be seeing some of the first galaxies and stars ever formed. The greater the distance we look into space, the further back in time we see. Being able to peer further will help give us some answers about how everything we know came to be.
We still understand so little about our universe. Thanks to these amazing telescopes, we will gain more answers to these fundamental mysteries. How much more will we learn about the cosmos in this lifetime? Only time (and space) will tell.
Source: https://www.jwst.nasa.gov/
Brooke Edwards is our area’s NASA/JPL Solar System Ambassador. She lives in Manistee and has given area presentations and hosted night-sky viewings at Fifth Avenue beach. Follow her group on Facebook: @BrookeEdwardsSolarSystemAmbassador
