Utah Skies

From the Earth we view the brighter outer planets Mars, Jupiter, and Saturn moving in their orbits around the Sun in an easterly direction.  At times these planets seem to stop in their eastward motion and reverse direction towards the west for a few months before they resume their normal eastward motion   Astronomers call this retrograde motion. 

For the next few mornings in the pre-dawn sky look south and you will see the bright red star Antares, followed by King Jupiter to the left and the ringed planet Saturn to the left of Jupiter.  

The star Arcturus glows brightly in the eastern sky in the spring and summer months. It is the fourth brightest star in the sky. It has a distinct yellowish color and when noticed in the eastern sky you will know that spring is about to arrive. 

A group of astronomers using the Japanese Subaru 8-meter telescope, located on the top of the mountain Mauna Kea in Hawaii has discovered an object in the extreme outer portions of the solar system on November 18, 2018.  

Sirius is the most luminous Star in the Sky and is easily observed this month about 1/3rd of the way up the southern sky around 9 p.m. Only our Sun, the moon, Venus, and Jupiter, are brighter. Sirius is the 10th closest star to the earth being only 8.7 light years away, about twice the size of our sun, and about 20 times brighter. 

Tomorrow we wake up to a new season. Spring begins at 3:44 p.m. MDT— the moment of the vernal equinox. It occurs when the Sun crosses Earth’s equator from south to north. We look forward to longer and warmer days. 

One of the exciting adventures of astronomy is to find other planets like the earth orbiting other stars. The first such planet was found in 1992. On March 6, 2009, NASA launched a planet-hunting satellite called Kepler. Its job was to stare at a spot in the sky containing 150,00 stars,  in the Constellation Cygnus, looking for dips in starlight as an orbing planet passed between us and its sun. Kepler collected this data in two missions.  

The New Horizon Spacecraft was launched on its journey to the outer solar system on January 19, 2006. It arrived at the minor planet Pluto more than nine years later on July 14, 2015. It revealed an amazing amount of detail about Pluto that was previously unknown, such as kilometer high mountains made of solid ice, craters, cry-o-volcanoes, and plains made of nitrogen ice.

The famous astronomer Nicolaus Copernicus first proposed that the sun rather than the earth was at the center of the Solar System. Legend has it that Copernicus never saw the planet Mercury. This is understandable considering that the planet Mercury hugs the horizon even when at its highest elevation in the sky.

One of the great sites of the night skies are comets. Comets are small objects made up of dust and rocks. Comets come in the inner solar system from the outer region beyond Pluto.