Science: James Webb Space Telescope Turns On

The Story:

The James Webb Space Telescope is now in position in deep space, and all of its instrumentation has been turned on, including the primary instrument, the Near Infrared Camera, in NICam. The next step is for the mission operations team to turn off the instrument heaters.


The heaters have been essential in keeping critical parts warm during the flight to the destination, the gravity ‘Lagrange point.’ Now, though, it is necessary for the team to shut down the heaters to allow the instruments to get to their final temperatures, designed to optimize their performance.

What is the significance of infrared light, and the near-infrared part of the visible spectrum? Space is full of dust, that is, small particles that an effective telescope should see passed. The long waves of infrared light can see through dust, whereas full-spectrum visible light scatters around on it.

The Thing to Know:

As the telescope peers outward, it will in effect be looking backward in time, to a limit defined by the Big Bang. If the now-standard theory of cosmology is right, the size of galaxies should get smaller as one goes “backward,” because galaxies took their time consolidating. If there turn out to have been large galaxies earlier than there ‘should’ have been, then something is very wrong with the standard model and astrophysicists will have to go back to their drawing boards.


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