The planets spice up the night ... adding surprise and delight! Their dances with the setting and rising Sun, the phases of the Moon, the twinkling stars and each other are heavenly treats that fill our hearts with unforgettable images.
Is it a planet? ... What planet? When you look up at the night sky, how do you know you are looking at a planet? Keep reading and you'll find out!
Note: 2003 UB313 has officially been named Eris.
The Planets Defined
The International Astronomical Union, meeting in Prague August 24, 2006, voted and agreed that a "planet" is defined as a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.
This means Pluto has been reclassified and we no longer have 9 planets. The 8 remaining planets in our solar system are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
The International Astronomical Union decided on the term plutoid as a name for dwarf planets like Pluto. IAU Press Release 6/11/08
A plutoid is a celestial body orbitting around the Sun at a greater distance than Neptune. It assumes a near-spherical shape, and has not cleared the neighbourhood around its orbit. Satellites of plutoids are not plutoids themselves.
As of June 11, 2008 the two known and named plutoids are Pluto and Eris. It is expected that 42+ plutoids will be named as science progresses and new discoveries are made.
Planets Plus Earth's Moon
to background: Neptune
(furthest from Sun), Uranus,
Planetary Mnemonic ~ 8 Planets
Mnemonic ~ 9 Planets
Planetary Mnemonic ~ 8 Planets + 3 Dwarf Planets
The planets follow the path of the Sun and Moon. If you watch the Sun travel across the sky during the day and the Moon during the night, you will become acquainted with their path from horizon to horizon. This path is called the ecliptic and changes only slightly with the seasons. If you find an unusually bright non-twinkling object in the night sky along this path, it is probably a planet.
Planet Are You Looking At?
This planet is not visible to the naked eye.
This planet is rarely visible to the naked eye however, annually, a few weeks before and after its opposition, Uranus reaches the faint visible magnitude 6.0 and can be seen by the unaided eye in a dark country sky. See Planets 2001-2030 to find the planet's dates of opposition, currently occurring in September and October.
Small yellowish-white Saturn is generally seen in the night sky.
Jupiter is usually found in the night sky far from the Sun. It is large and glows a brilliant white light.
Venus can be found near the horizon at sunset or sunrise. It is large, extremely brilliant, silvery in color and often mistaken for a UFO!
This elusive planet is only occasionally seen low in the eastern sky before sunrise, or low in the western sky after sunset. It is often hidden in the glowing embrace of the Sun. Elusive Mercury is the only planet that twinkles, flashing a bright yellow color.
*Both Mercury and Venus may appear as crescents, while the other planets will always appear full. Most observers only see the crescent shape through a telescope.
Where Are the Planets Now?
Check out the helpful links on this page.
Spiritual, Astrological Qualities
Current Scientific Knowledge, History, Mythology
Panets ... Tour the Solar System (includes Pluto and its moons)
a night sky traveler!
like to know your thoughts about The Night Sky and
Started in Astronomy
At Skymaps.com download a current monthly guide, evening sky map & calendar.
Link to Sky and Telescope's This Week's Sky at a Glance.
Spaceweather.com keeps you looking up!
Questions? Answers? Impressions?