James webb vs hubble images10/2/2023 It’s a sort of follow-up to one of the Hubble Space Telescope’s greatest contributions to astronomy: the Hubble Deep Fields, a series of images that show distant galaxies in incredible detail. This same concept applies to light!īecause all galaxies are moving away from us due to the expansion of the universe, the light they produce is being stretched into longer wavelengths.On Monday, NASA - in tandem with the White House - released an incredible deep-field image taken by the James Webb Space Telescope (JWST), which demonstrates how this telescope will be able to look back at some of the earliest galaxies which lit up the cosmic dawn. This effect is known at the Doppler shift: sound waves produced by an object moving towards you are compressed, while they are stretched as the waves move away from you. Have you ever noticed the sound of an ambulance changing as it drives past you? It is higher pitched as it moves towards you, and lower pitched as it drives away. Since those galaxies are very distant, their light has been stretched, in a phenomenon known as redshift, to infrared wavelengths by the time it reaches Webb. The very first galaxies ever created in the universe are best observed in the infrared. Advantages of infrared observationsĬertain objects in space like planets, red stars and brown dwarfs are too cold to emit much visible light and are most visible in the infrared.īecause infrared light wavelengths are longer than those of visible light, they can penetrate dust clouds more easily, which allows astronomers to peer inside nebulae to see newly forming stars and planets that would otherwise remain hidden. Webb is able to peer through cosmic dust to study colder or very distant objects. While Hubble focuses mainly on light that is visible to the human eye, Webb's four scientific instruments were specifically designed to capture infrared light. (Credit NASA/ ESA/Hubble Heritage Team ( STScI/ AURA)) Why study infrared light? Observing infrared light allows scientists to penetrate the dust and study otherwise unseen parts of our universe. The Pillars of Creation in the Eagle Nebula can be seen in visible (left) and infrared (right) light as observed by the Hubble Space Telescope. This will depend on how long its propellant (needed to keep Webb stable in its orbit) will last. The minimum expected lifetime of Webb is 5 years, but it may go beyond 10 years. Hubble was launched in 1990 and will remain operational as long as its instruments are functioning. Webb is too far from Earth to repair, which is why it went through unprecedented testing before launch. Astronauts famously corrected Hubble's mirror in 1993 using Canadarm, Canada's robotic arm on the American Space Shuttle. Low Earth orbit, at an altitude of 547 kmġ.5 million km away from Earth (at a point in space known as Lagrange 2)ĭue to its location, Hubble can be repaired and upgraded while in orbit. Ultraviolet, visible and near-infrared light (Credit: European Space Agency (ESA)/M. Kornmesser)Ībout the size of a tennis court due to its large sunshieldġ8 hexagonal mirror segments, for a total width of 6.5 m Webb's larger mirror allows it to capture more light and see farther into the cosmos. A comparison of the Hubble Space Telescope and the James Webb Space Telescope.
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