Caption: The Martian moons are Phobos (mean radius 11.1 km) and Deimos (mean radius 6.2 km) are shown to-scale with Mars which means they are NOT visible without doing a triple-click to see the enlarged image. Although the image is to-scale, but may be a collage, NOT a single image. The vertical of the image is, more or less, Martian east-west.
The Martian moons are both irregular in shape because they are too low mass to have been pulled into spherical shape by self-gravity
The commonest origin theory is that the Martian moons are captured asteroids, but rival theories exist (see Wikipedia: Moons of Mars: Origin).
The Martian moons were discovered in 1877 during the same FAVORABLE opposition that resulted in emphasis given to the possible existence of the Martian canals. They were discovered by Asaph Hall (1829--1907) at the US Naval Observatory (USNO) in Washington, D.C..
Jonathan Swift (1667--1745) (in Gulliver's Travels (1726, 1736)) and Voltaire (1694--1778) fictionally predicted that Mars would have 2 moons. Craters on Deimos are named for Swift and Voltaire. And who can forget that immortal yarn The Secret of the Martian Moons (1955) by Donald A. Wollheim (1914--1990). Vote now for Crater Wollheim.
Credit/Permission: NASA,
2007
(uploaded to Wikipedia
by Magnus Manske,
2008) /
Public domain.
Image link: Wikipedia:
File:Mars Moons Orbit distance flipped.jpeg.
Local file: local link: martian_moons_to_scale.html.
File: Mars moons file:
martian_moons_to_scale.html.