Interacting galaxies Arp 142 (MIRI image, annotated)

This image of interacting galaxies Arp 142, captured by the James Webb Space Telescope’s MIRI (Mid-Infrared Instrument), shows compass arrows, scale bar, and colour key for reference.

The north and east compass arrows show the orientation of the image on the sky. Note that the relationship between north and east on the sky (as seen from below) is flipped relative to direction arrows on a map of the ground (as seen from above).

The scale bar is labelled in light-years, which is the distance that light travels in one Earth-year. (It takes three years for light to travel a distance equal to the length of the scale bar.) One light-year is equal to about 9.46 trillion kilometres.

The scale bar is also labelled in arcminutes, which is a measure of angular distance on the sky. One arcsecond is equal to an angular measurement of 1/3600 of one degree. There are 60 arcminutes in a degree and 60 arcseconds in an arcminute. (The full Moon has an angular diameter of about 30 arcminutes.) The actual size of an object that covers one arcsecond on the sky depends on its distance from the telescope.

This image shows invisible near- and mid-infrared wavelengths of light that have been translated into visible-light colours. The colour key shows which NIRCam and MIRI filters were used when collecting the light. The name of each filter is the visible light colour used to represent the infrared light that passes through that filter.

[Image description: Two interacting galaxies known as Arp 142 in a horizontal image taken in mid-infrared light. At left is NGC 2937, which looks like a tiny teal oval and is nicknamed the Egg. At right is NGC 2936, nicknamed the Penguin, which is significantly larger and looks like a bird with a fanned tail.]

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