How NASA creates the James Webb Space Telescope images

Hours Image processing work has gone into each of the five color James Webb Space Telescope images released by NASA this week.

Why is this important: Through its photos, the JWST – which captures light in wavelengths the human eye cannot see – will change the way the public and scientists understand the history of the universe.

Where is it : The JWST looks at the universe in infrared light, allowing it to cut through dust to see the intimate details of star formation and even the faint light of some of the earliest galaxies that formed over 13 billion years ago. ‘years.

  • “Biologically, we just don’t have the ability – even if we’re floating next to these objects – to see them the way Hubble or Webb can see them,” said Joe DePasquale, an image processor who works with JWST, in Axios.

How it works: When photos taken by JWST’s huge mirror are beamed back to Earth, they appear mostly black, DePasquale says.

  • “Each pixel in the image has over 65,000 different shades of gray,” he said, adding that “the universe is very dark,” so most of the interesting parts of a JWST image are “buried in the darkest regions of the image.”
  • The imaging team must then brighten the darker parts of the image to bring out the hidden detail in the pixels without oversaturating the brightest parts of the image – which may be galaxy cores or bright stars. .

The JWST is so sensitive that it is able to differentiate bands of infrared light the same way our eyes can see different bands of optical light – which we perceive as colors.

  • Due to this sensitivity, the imaging team is able to sort out the longs and the shorts wavelengths of infrared light, allowing them to filter the image through different colors in a scientifically sound way.
  • The human eye perceives longer wavelengths of optical light as red, so color replaces longer wavelengths of infrared light. Blue is used for shorter wavelengths and the other colors of the rainbow fall in between.
  • “If you had infrared eyes sensitive to this light, maybe that’s what you would see,” Klaus Pontoppidan, a JWST project scientist, told a news conference.

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