Mars is closest to the sun today

[ilan]

Mars is closest to the sun today
Deborah Byrd in ASTRONOMY ESSENTIALS | SPACE | September 16, 2018

On September 16, 2018, Mars reaches perihelion, its closest point to the sun in its 2-year orbit. Mars’ brightness in July and August – and a recent global dust storm on the planet – are both linked to this event.


True color image of Mars taken by the OSIRIS instrument on the ESA
Rosetta spacecraft during its February 2007 flyby of the planet. Image via ESA.

The red planet Mars swings to perihelion – its closest point to the sun in its orbit – on September 16, 2018. Mars’ orbit around the sun lasts 687 Earth-days, or about two Earth years. At perihelion, it is 1.38 AU (astronomical units) from the sun. That’s 1.38 Earth-sun distances.

Mars’ perihelion is a once-in-two-Earth-years event. Mars came to perihelion last on October 29, 2016. Its next perihelion will be August 3, 2020.

None of the planets have exactly circular orbits, but most, like Earth, have orbits around the sun that are nearly circular. On the other hand, Mars’ orbit is much more elliptical, more like a circle that someone sat down on and squashed. Its distance from the sun varies between 1.38 AU and 1.67 AU – a variation of over 20 percent. From perihelion (closest point) to aphelion (farthest point), Mars receives 31 percent less heat and light from the sun.
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Although this occurred two days ago, Mars is still nearly at perihelion, so the information is timely. - ilan