The Celestial Sphere

By Matthew Johnson

In the final hours of Dec. 31, 2023, the sun produced a X5.0 solar flare (R3 Strong Radio Blackout), the largest flare observed by the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center since 2017. There was also a Coronal Mass Ejection (CME) related to this event.

This was important information for the Earth. 

Solar flares emit radiation, mostly in the form of ultraviolet light and X-rays. The radiation reaches the sunlit side of Earth within eight minutes, traveling at the speed of light. According to the Space Weather Prediction Center, these energetic blasts can interfere with radio signals, which is what happened on Dec. 14, 2023, when a strong solar flare interrupted aircraft communications for a short time.

CMEs are highly magnetized clouds of the sun’s plasma emerging from the sun’s outer atmosphere, known as the corona. As this cloud radiates outward, it carries the sun’s magnetic field with it. It takes between 15 hours and a few days for the cloud to reach the earth. CMEs can collide with the earth’s magnetosphere, the barrier that protects it from the harshest impacts of space weather. It is this collision that produces what are termed geomagnetic storms—space weather that can be viewed as an aurora borealis, or northern lights. They are produced by the storm’s electrons colliding and following the Earth’s magnetic field lines toward its northern and southern poles, where the particles then collide with Earth’s atmosphere and produce the glowing and shimmering lights of an aurora.

The sun goes through an 11-year cycle of minimum-to-maximum activity called the solar cycle. Scientists announced that a solar minimum had occurred in December 2019, marking the end of Solar Cycle 24 and the commencement of Solar Cycle 25, the 25th such cycle since extensive recording of such solar activity began in 1755.

The solar cycle can be followed by using a properly filtered telescope to count the number of sunspots—regions of intense magnetic activity—on the sun’s surface. The sun will have the fewest number of sunspots at the beginning of a solar cycle, its solar minimum. The number of sunspots increases over time proportional to solar activity. The solar maximum is in the middle of the cycle when there are the most sunspots. As the cycle ends, it fades back to the solar minimum, and a new cycle begins.

Forecasting the solar cycle and monitoring for flares and ejections can help scientists protect power grids and radio communications and keep satellites and astronauts safe.

Meteor Showers
There are no meteor showers in February, although there will always be an occasional meteor.

Viewing
Mercury is too close to the sun to observe. On Feb. 14, just before the sun rises, Venus can be seen just above Mars in the southeast, while during the night Jupiter will be poised just to the left of the moon. From Feb. 20 to 24, the planets Venus and Mars form a close conjunction and can be seen by looking southeast before the sun rises.

Saturn is low on the southwest horizon and difficult to observe. On Feb. 3, it can be viewed about an hour after sunset. Uranus can be viewed with binoculars that evening, between Jupiter and the Pleiades star cluster. Neptune, the most distant planet, can possibly be viewed with binoculars to the upper left of Saturn on Feb. 11.

Moon Phases
Feb. 2: Last quarter (left half of the moon illuminated).

Feb. 9: New moon (no visible moon). The best time of the month to observe faint objects such as distant galaxies and star clusters is during the few days before and after the new moon. 

Feb. 16: First quarter (right half of the moon illuminated).

Feb. 24: Full moon.

February’s full moon was known by Native American societies as the Snow Moon, since February snowstorms are often the heaviest of the year. Some named it the Hunger Moon owing to scarce food sources and difficult hunting conditions during midwinter, while others named it the Storm Moon.

In scientific terms, February’s full moon is termed a “micromoon.” This is because the moon is at apogee, the furthest point in its orbit around the earth, and thus appears slightly smaller than normal. This month the micromoon will be approximately 252,225 miles from Earth.

Don’t forget that there is an extra day added to the month of February this year.

Matthew Johnson and Aton Forest will sponsor a solar observing session with dedicated solar telescopes for this winter’s Weekend in Norfolk, Feb. 24-25. See the WIN website for a list of events, times and other details.