Science behind Aurora Borealis

Presentation by Randy Hemann

The Aurora Borealis, or Northern Lights, is a breathtaking natural phenomenon caused by the interaction of charged particles from the Sun with Earth’s atmosphere. The Sun constantly emits a stream of charged particles known as the solar wind. When these particles encounter Earth’s magnetic field, they are deflected towards the poles. As these particles collide with atoms and molecules in the upper atmosphere, they excite the gases, causing them to emit light in various colors, primarily green and red, creating the mesmerizing displays of light we know as the aurora.

Dr. Randy Hemann is president of the Rochester Astronomy Club and NASA Solar System Ambassador. Randy is a retired physician and former chief medical officer from Rochester, Minnesota. His interest in astronomy was planted at age 10 in his backyard on a cold winter night when his 3-inch reflector telescope “discovered” Saturn as this new “star” entering the constellation of Orion. That indelible impression never left him. Later in life, after extensive education in medicine and establishing his career, he purchased a 6-inch reflector telescope from a friend — and then it began. He joined a local amateur astronomy club and has performed as its president for the last 25 years. He enjoys producing daytime and nighttime astronomical outreach events for local schools, scouts, libraries, and regional state parks. Now retired, he and his wife Lynne travel the country in his motorhome, always toting several telescopes for impromptu campsite night observing sessions with others. He often pulls a trailer that houses his 18- and 30-inch Dobsonian telescopes for more extensive observing opportunities.

Observing

Public Sky Observing of the young Moon – 6.9 days after New Moon, planets Mars Jupiter Uranus bright stars, double stars, and more by telescope with guidance members of the Rochester Astronomy Club.

NASA and Astroleague have prepared an observing challenge for the general public on the 35th anniversary of the Hubble launch. To earn a silver certificate, you must do some outreach (on the web or in person) and observe at least one featured object each month and take a photo or draw it. Submit no later than the end of the following month. See more at Astroleague, NASA – April .

What to expect at Public Sky Observing – click here.

Reload this page before you leave for the event. Event can be cancelled in case of cloudy weather or another reason.

Moon on Friday April 4 evening

Credit: NASA Scientific Visualization Studio

Resources: In the Sky April/2025, Phases of the Moon 2025, Planets rise and set 04/04, Sun and Moon 04/04, Sun today, Holidays 2025
Moon Features You Can See From Earth,
Messier list, Caldwell list, Double stars list, Carbon stars list

☿ – Mercury, ♀ – Venus, ♂ – Mars, ♃ – Jupiter, ♄ – Saturn, ⛢ – Uranus, ♆ – Neptune

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