What’s Up in 2025?

2024 in Review

2024 was a banner year for astronomy. The main event was the total solar eclipse in April. I wrote a short blog post about the eclipse the next day, and I followed it up with a more detailed report later. The latter blog post included a connection to my first solar eclipse (albeit a partial eclipse) 54 years earlier and a time-lapse video of this eclipse. It will be two decades before we in the United States will be treated to another total solar eclipse.

Eclipses are predicted far in advance, but in astronomy, we sometimes have unexpected things arise. Just a month after the eclipse, the largest solar flare in two decades occurred. Situated at the center of the sun’s visible disk, the charged particles the solar flare spewed headed straight for earth, and the next night the sky was lit up with an aurora seen across the United States. Unfortunately for me, it was mostly cloudy in Northern Kentucky that evening. I saw the aurora between the clouds for perhaps 15 minutes before the sky became completely overcast. Five months later, another solar flare occurred. Though not as powerful as the flare in May, an alert went out to be on the watch for auroral activity. I happened to be with a few friends at the Johnson Observatory behind the Creation Museum on the evening of October 10. I kept an eye out, but I didn’t see anything until a bit past 9:30 p.m., about the time my guests were thinking of going home. Suddenly, an aurora put on quite a display for about a half hour. Solar flares occur around sunspots, and sunspot cycle 25 peaked in 2024. The sunspot activity will remain high throughout 2025, so there likely will be some solar flares this year. Therefore, be on the watch for more aurorae this year.

Also in early October, there were predictions of the naked-eye visibility of Comet Tsuchinshan–ATLAS, a recently discovered comet. Comet Tsuchinshan–ATLAS turned out to be the brightest comet in years. Cloudy weather prevented me from seeing the comet on its peak nights, but I first spotted it on October 17. I took photographs several evenings, with my best photographs taken under the dark skies of Red River Gorge on October 21. Have I ever mentioned my obsession with Red River Gorge? I lead field trips there. You can find out more and sign up for an excursion to Red River Gorge here.

Will There Be Big Things in 2025?

As for predicted things, no. There are no total solar eclipses this year, but there will be two total lunar eclipses, one on the night of March 13–14 and one on the night of September 7–8. The September lunar eclipse will be visible in Australia, Asia, Africa, and Europe. The United States will have a ringside seat for the March eclipse. We will have an eclipse watch party at the Johnson Observatory at the Creation Museum. You can sign up here but be advised that this free event is in the middle of the night—in late winter. So, if you join us, be sure to dress warmly.

As I’ve already mentioned, there ought to be plenty of sunspots every day in 2025. Be aware that if you visit the Creation Museum this summer, you may see me out front with a telescope and filter for safely viewing the sun. We call this program Sunspotting. We do Sunpotting 10:00–11:00 a.m., Monday–Friday, on clear summer days when I’m available. Sunspots are way cool! (7,000–8,000ºF as compared to 10,000ºF for the rest of the sun’s surface!) So why don’t you come by and take a look?

Will there be another bright comet this year? Again, we can’t predict these things. I consider it unlikely, but you never know. Stay tuned for announcements of any new bright comet discoveries.

Before reviewing the things that we know will happen this year, let me revisit some unfinished business from 2024. In March, I blogged about T Coronae Borealis, a recurrent nova that erupts about every 80 years. T CrB normally is far too faint to be seen with the naked eye, but when it erupts, T CrB is about as bright as the North Star for a night or two. There were some indications that 2024 was going to be the year T CrB would erupt (the last time was in 1946), with the eruption most likely happening by September 2024. Well, it didn’t happen. That makes it more likely that T CrB will brighten in 2025. Or maybe not. I’ve been checking on T CrB every clear evening and/or morning since early March. I even took some “before” photographs to compare to an “after” photograph. T CrB will brighten only for a night or two before it slips below naked-eye visibility again. I just hope T CrB erupts on a clear night so that I can take the second photograph. I’d hate to wait until I’m 150 years old to finish this project.

As the year begins, four of the five naked-eye planets will be visible in the evening sky.

What Will Happen in the 2025 Skies?

As the year begins, four of the five naked-eye planets will be visible in the evening sky. The brightest planet is Venus. Look for it as a very bright star in the southwestern sky in the evening twilight. If you have even a small telescope, the first two-and-a-half months of 2025 will provide a great opportunity for an observing project, particularly for homeschoolers. Throughout 2024, Venus was not impressive when viewed through a telescope. This was because Venus was on the far side of the sun at midyear (an event we call superior conjunction), with Venus approaching that position in the first half of 2024 and leaving that position in the second half of 2024. Consequently, Venus appeared small and nearly fully lit during much of 2024. However, as 2025 begins, Venus is rapidly approaching the earth. When viewed through a telescope in January, Venus will be half lit, and its apparent size will noticeably increase each week. By February, Venus will assume a crescent shape, and Venus’ apparent size will increase each week. In early March, the crescent will thin and increase in size. In mid-March, Venus will plunge toward the sun, passing between us and the sun (an event we call inferior conjunction), and will not be visible for a couple of weeks.

Venus

Venus will reappear in the morning sky by late March, appearing as a bright star low in the eastern sky during morning twilight. Viewed through a telescope, Venus will go through the changes it showed in the first part of the year but in reverse order. At first, Venus will be a large, thin crescent, but each week the crescent will thicken, and Venus will appear smaller. By June, Venus will appear half lit. After that, Venus will continue to shrink and approach being fully lit. By the end of 2025, Venus will pass through superior conjunction, departing the morning sky and shifting back to the evening sky early in 2026. As I said, when viewed through a telescope, Venus will put on quite a show for the first half of 2025, when it is near inferior conjunction. The synodic period is the time over which the visibility of a planet repeats. The synodic period of Venus is 584 days, a little more than 19 months. So, if you miss this opportunity to watch Venus in 2025, you will have to wait until late summer and autumn of 2026.

Saturn

Saturn begins the year in the evening sky, but, like Venus, it will soon leave the evening sky. At the beginning of the year, Saturn will be a moderately bright star east (in the Northern Hemisphere, left) of Venus. However, the separation of Venus and Saturn will diminish quickly, with the two planets being about two degrees apart on the evening of January 18. After that, Saturn passes to the right of Venus and will approach conjunction with the sun in early March. By the end of February, Saturn will be difficult to see in the evening twilight. Look for Saturn to reappear in the eastern morning sky by mid-April. Saturn will remain in the morning sky until September 20, when it reaches opposition to the sun and once again becomes an evening object. Actually, you will be able to see Saturn in the evening a bit before this, if you wait for it to rise.

Nearly everyone knows that Saturn has majestic rings. A less well-known fact is that even a small telescope will reveal Saturn’s rings. Except in 2025. Saturn and its rings are tilted 26.7 degrees to its orbital axis. Saturn takes 29.5 years to orbit the sun. As Saturn orbits the sun, the apparent tilt of Saturn’s rings changes. The rings are most impressive when the tilt we see is near maximum. However, twice each Saturnian orbital period, the earth passes through the plane of Saturn’s rings. Saturn’s rings are very thin (at most a few hundred feet), and Saturn is nearly a billion miles away. Therefore, when we pass through the ring’s plane, Saturn’s rings entirely disappear, even when viewed through the largest telescopes. In 2025, we pass through the ring plane twice, once in March and again in November. March would be the better opportunity to see a ringless Saturn, but Saturn will be in conjunction with the sun then, rendering it at best very difficult to see Saturn (though orbiting telescopes probably will photograph it). Between March and November, the rings will be barely visible through very large telescopes. If you want to see Saturn’s rings at their worst, this is the year. Or you can wait another 15 years.

Jupiter

Jupiter reached opposition to the sun in early December 2024, so it will be the dominant planet in the evening sky throughout the first half of 2025. At the beginning of the year, Jupiter will be the bright star low in the eastern sky. Each successive evening, Jupiter will move slightly to the west, disappearing in the western sky in the evening twilight by mid-June. Look for Jupiter to reappear in the eastern morning sky by mid-July. Through even a small telescope, the disk of Jupiter will be visible, as well as Jupiter’s four Galilean satellites. We call these the Galilean satellites because Galileo discovered these natural satellites, or moons, with his telescope four centuries ago. The Galilean satellites have obvious changes in position from one night to the next. Observing and plotting the positions of the Galilean satellites each evening is a fun and educational project.

Mars

Mars reaches opposition to the sun on January 15, so Mars will be visible in the evening sky throughout 2025. Opposition is when a planet is opposite the sun in the sky, rising at sunset and setting at sunrise. For superior planets (planets orbiting farther from the sun than the earth), opposition is when they are closest to earth. Since the orbits of Jupiter and Saturn are so large, their relative distances from the earth don’t change much, so it doesn’t matter if we observe them at opposition or some other time. However, since Mars orbits the sun just beyond the earth, its relative distance changes dramatically. And Mars is a small planet (it’s only half the earth’s size). Consequently, Mars usually appears very small when viewed through a telescope. Mars appears largest through a telescope when Mars is near opposition. So, as the new year begins, Mars is well-placed for viewing, but you better act quickly because the distance between the earth and Mars steadily increases throughout 2025. On average, Mars comes to opposition with the sun once every 26 months. If you miss this opportunity to see Mars at its best, you’ll have to wait until early 2027 to see it this well again.

Speaking of Mars, on the night of January 13–14, the moon will occult (pass in front of) Mars for those in the United States. To find the times of disappearance and reappearance of Mars, consult this website. I have it set for Cincinnati, but you can change it for your location. The moon will be nearly full, so it will be difficult to see Mars as it passes behind and then reappears. To see this occultation, you will probably need a pair of binoculars or a small telescope. The moon also will occult the Pleiades star cluster on the night of February 5–6, but this event will be best viewed by people in the western United States.

Mercury

What about Mercury? Being so close to the sun, Mercury is difficult to see. It is best seen for a week or two when it is at its greatest elongation from the sun. Mercury is at greatest eastern elongation from the sun on March 7, July 3, and October 29. Look for Mercury low in the west in evening twilight for a few days on either side of these dates. I expect that early March will be the best opportunity. Mercury’s greatest western elongation from the sun occurs on April 21, August 19, and December 7. Look for Mercury low in the eastern sky in morning twilight for several days around these dates. I think August and December will be better than April for doing this.

Meteor Showers

The Perseid meteor shower will peak on the morning of August 12, but the meteor shower will be good over a few nights on either side of the peak. While this is a reliable meteor shower, the peak is only a few days after the full moon, with the bright waning gibbous moon rising about the end of twilight on August 9. Therefore, moonlight will interfere with all but the brightest Perseid meteors, diminishing the number of meteors that you will see. Much better will be the Geminid meteor shower, which will peak on the morning of December 14, with good numbers over several nights. The waning crescent moon will rise in the early morning hours, but its light should not interfere with the meteors much. With both meteor showers, you will see more meteors after local midnight than before local midnight.

Get out and enjoy the sky that God gave us!

Keep in mind that an unanticipated astronomical event may arise in 2025. If so, I’ll try to inform you in future blog posts. Meanwhile, get out and enjoy the sky that God gave us (Psalm 19:1)!