Welcome to Fall

Welcome to the beginning of fall, defined by the autumnal equinox (in the northern hemisphere) or the southward equinox (hemisphere-neutral).


On the day of the equinox, the Sun appears to rise “due east” and set “due west”.  In Denver, the equinox this year occurs at 7:03:34 pm MDT on September 22, 2022.

Vernal equinox and autumnal equinox: these classical names are direct derivatives of Latin (ver = spring, and autumnus = autumn). These are the historically universal and still most widely used terms for the equinoxes, but are potentially confusing because in the southern hemisphere the vernal equinox does not occur in spring and the autumnal equinox does not occur in autumn. The equivalent common language English terms spring equinox and autumn (or fall) equinox are even more ambiguous. It has become increasingly common for people to refer to the September equinox in the southern hemisphere as the Vernal equinox.  Confusing!

To avoid confusion use northward equinox and southward equinox, names referring to the apparent direction of motion of the Sun. The northward equinox occurs in March when the Sun crosses the equator from south to north, and the southward equinox occurs in September when the Sun crosses the equator from north to south.

Welcome to Fall in Denver!  Just remember, winter is coming, otherwise known at the December solstice, also known as the southern solstice on December 21 (in Denver).

Mars 2020 – Countdown to Landing

On Thursday, February 18, 2021 at about 1:55pm MST the Perseverance rover and the Ingenuity helicopter drone will land on Mars! The NASA TV broadcast from Mission Control starts at 12:15pm MST. 

Watch live online the events on Earth with “some” delay from Mars.

The Perseverance rover has four science objectives that support the Mars Exploration Program’s science goals:

Looking for Habitability: Identify past environments capable of supporting microbial life.
Seeking Biosignatures: Seek signs of possible past microbial life in those habitable environments, particularly in special rocks known to preserve signs of life over time.
Caching Samples: Collect core rock and “soil” samples and store them on the Martian surface.
Preparing for Humans:

Test oxygen production from the Martian atmosphere.

  • Mission Name: Mars 2020

  • Rover Name: Perseverance

  • Main Job: The Perseverance rover will seek signs of ancient life and collect rock and soil samples for possible return to Earth.

  • Launch: July 30, 2020, Cape Canaveral Air Force Station, Florida

  • Landing: Feb. 18, 2021

  • Landing Site: Jezero Crater, Mars

  • Mission Duration: At least one Mars year (about 687 Earth days)

  • Tech Demo: The Mars Helicopter is a technology demonstration, hitching a ride on the Perseverance rover.

More information and other stuff at NASA Mars Landing Toolkit.