http://upload.wikimedia.org/wikipedia/commons/7/73/Plane_of_ecliptic.gif

    Caption: "The ecliptic plane is illustrated in this Clementine spacecraft (1994--1995) star tracker camera image which reveals the Moon lit by Earthshine, the Sun's corona rising over the Moon's dark limb, and the planets going leftward:
    1. Saturn.
    2. Mars.
    3. Mercury.
    The ecliptic plane is the plane of the Earth's orbit around the Sun. In the course of a sidereal year (365.256363004 days, J2000), the Sun's apparent path through the sky lies in the ecliptic plane. The planetary bodies of our Solar System all tend to lie near the ecliptic plane, since they were formed from the Sun's spinning, flattened protoplanetary disk. The snapshot nicely captures a momentary line-up in the ecliptic plane." (Slightly edited.)

    Features:

    1. The shown planets don't exactly line up because their orbits have orbital inclinations from the ecliptic plane: for Mercury 7.005°, for Mars 1.85°, and for Saturn 2.49°.

    2. Since the outer planets Saturn and Mars are closer to the Sun than the inner Mercury in projection on the sky, they must be on the far side of their orbits relative to the Earth.

    3. It's hard to say where Mercury is on its orbit, except that it's NOT aligned with the Sun from the point of view of Clementine.

    4. The image actually looks at bit fake, but it's real. The night side of the Moon is illuminated by Earthshine---which yours truly couldn't fathom at first even though it's said right in the official caption quoted above.

    Credit/Permission: NASA, before or circa 2009 (uploaded to Wikipedia by George Watson (AKA User:Dendodge), 2009) / Public domain.
    Image link: Wikipedia: File:Plane of Ecliptic.jpg.
    Local file: local link: moon_clementine.html.
    File: Moon file: moon_clementine.html.