The NASA Parker Solar Probe is speeding towards the Sun to begin its mission but that doesn’t mean it can’t take a moment to look back at where it came from. On September 25, the probe snapped a picture of Earth from 43.5 million kilometers (27 million miles) away.
The image (on the right-hand side of the picture above) was taken using the Wide-field Imager for Solar Probe, or WISPR, which is made up of two telescopes pointing at slightly different views of the sky. The outer telescope took the image of the Earth. The instrument will be used to observe features in the Sun’s atmosphere, like its Corona, before the probe passes underneath.
Zooming in on the Earth reveals a little bump on its right side, which is none other than the Moon peeking out from behind our planet. While Earth certainly takes center stage in this picture it is not the only astronomical feature worth noting. The Pleiades star cluster is just to the left of the Earth in the same panel. And the stars known as Bellatrix and Betelgeuse can be seen at the bottom of the second image, which was taken by the probe's inner telescope and can be seen on the left-hand side of the picture above.
The panel that contains the Earth also has a big lens flare in the middle, due to the brightness of the Earthshine. Shots containing Mercury and Venus might create similar effects in the future, but they won’t have much of a scientific impact. The features this telescope is looking for will be faint so it is set up to focus on those rather than the brighter objects.
The probe performed its first flyby of Venus on October 3 and has almost reached its first close encounter with the Sun. Known as its perihelion, this will happen on November 6 when the probe will be 24.1 million kilometers (15 million miles) from the surface of our star, slightly more than half the distance between Mercury and the Sun. It will eventually pass as close as 6.9 million kilometers (4.3 million miles) from the Sun. At its closest approach, it will reach the incredible speed of 690,000 kilometers (430,000 miles) per hour.
The probe is named after physicist Eugene Parker who predicted important aspects of solar physics and came up with the term “solar wind” to describe the flow of particles that the Sun throws into the Solar System. The probe is expected to continue operation until 2026.