Bob Siederer
24 August 2026
Hello again Science fans!
August has been a month full of astronomical events, what with the total eclipse of the sun over much of Europe coinciding with the Persied meteor shower earlier this month. The fun continues with an almost total eclipse of the moon (96%) on Thursday evening, August 27 that will be visible here.
Eclipses occur when one astronomical body crosses in front of the sun with an alignment that blocks light to another body. For a solar eclipse, the Moon passes between us and the Sun at just the right distance to totally block sunlight from view, if you happen to be in the path of totality anyway.
For a lunar eclipse, Earth gets between the sun and moon such that the shadow cast by Earth blocks sunlight from reaching the moon. A lunar eclipse will always occur either before or after a solar one, but the opposite isn’t true, all due to orbital mechanics.
Astronomer Andrew Fraknoi has prepared an information sheet for the lunar eclipse that you can download here with times, diagrams, and viewing suggestions. Thanks to Andrew for providing this information!
We all live on Earth, a rocky planet with a rocky moon, orbiting a rather ordinary star, along with 7 other planets and assorted comets and asteroids. Our star exists near the end of one of the spiral arms of a galaxy we call the Milky Way, which contains billions more stars and planets.
Neither our Sun, nor the Milky Way itself look now like they did millions of years ago. The Milky Way has grown over time, forming new stars, as well as collecting stars, gas, and dark matter from other, smaller galaxies through mergers. We are still merging with the Sagittarius dwarf galaxy, and have been doing so for over 6 billion years. About 10 billion years ago, we merged with Gaia-Sausage-Enceladus, which significantly changed the structure of the Milky Way.
Using observations from the Hubble Space Telescope and the Gaia spacecraft, scientists now have determined we merged with a galaxy called LKH around 11.8 billions years ago, just 2 billion years after the Big Bang. How they discovered this is a tale!
Closer to home, the makeup of a rare meteorite provides history of an ancient planet that was once in our Solar system. It may have been as large as Mars. Again, the story of how astronomers determined this is fascinating.
A limited number of telescopes exist for astronomers to use to collect data. The existing telescopes look at different wavelengths of light, exist on different parts of the planet or in space, and have different resolutions. Up until now, astronomers have used a manual method to schedule who gets time on a particular scope, and how that time is used.
A couple of astronomers trained AI on the decisions astronomers made in determining where to point the telescope at any particular time. After many learning iterations, they now have an AI-driven model that can predict the best use of the telescope, and automatically aim it to the right spot in the sky.
Friday’s New York Times Science newsletter contained a picture of a poster hanging at the Jet Propulsion Laboratory near Pasadena which I’ve included above. It shows the distances various rovers have gone on both the Moon and Mars. Two are still active, Curiosity and Perseverance, both on Mars. While the poster itself dates to 2024, the numbers for these two rovers continue to be updated manually. Perseverance is expected to pass the distance record set by Opportunity, which ceased operation in 2018, within the next two weeks. It has about 590 feet to go to break the record.
A few months ago, we wrote about the Swift space telescope, which is in danger of reentering the atmosphere. NASA launched a crash program to develop a spacecraft to dock with Swift and push it into a higher orbit. Unfortunately, that mission failed and the rescue craft is spinning out of control. As a result, Swift will disintegrate during re-entry later this year.
Turning to AI, scientists trained a model on libraries of DNA and asked the model to create new, viral genomes. Of the hundreds or recipes created, 16 of them were viable. What could possibly go wrong?
Meanwhile, the FDA has approved Moderna’s new mRNA flu shot for adults 50 and over. It performs better than the existing standard-dose vaccine. Using mRNA technology should allow the flu vaccine to be adjusted to match dominant strains of the flu much faster.
What is the hardest substance in the human body? Tooth enamel. Its weakness is that it can’t regrow, unlike bones. Scientists have found a way to regrow enamel, and it could be available commercially next year! This could revolutionize dentistry.
Science communication is a topic we write about frequently here. UC Santa Cruz is offering two new introductory courses, both aimed at STEM professionals who want to learn about, or improve communications skills. The first course begins September 29. The second is planned for January, 2027. Both are online. Here’s more information on the courses, if you’re interested.
Have a great week in science!
Bob
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