Writes of Spring

4 April 2022

Spring is in the air, at least when it’s not snowing or sleeting. And with the season, a new round of discoveries has been sprouting.

All These Worlds

Exoplanets have been popping up like dandelions. Astronomers have now discovered more than 5,000 of them. There are now so many that we know how unusual our solar system is. But that’s just the beginning. The James Webb Space Telescope has seen first light, with a mission to study the early universe. But it will also discover countless more exoplanets, and might even see the first hints of life on other worlds.

Matters of Gravity

Black holes have been weighing on astronomers recently. One study showed how supermassive black holes dampen star production in their galaxies. This could explain why star production so quickly drops off after a time. Another study looked at how Hawking radiation might be simulated in the lab. It’s long been thought that black holes can slowly evaporate via Hawking radiation, but the effect has never been observed. So lab experiments could help us better understand it.

Black holes also power the gravitational waves we have observed so far, but we think there are other gravitational waves out there that were produced by the early inflation period of the universe. We don’t have a gravitational wave observatory that can see them, but one team thinks we might be able to use the Moon as a gravitational wave telescope. It’s an interesting idea if we can get it to work.

Dark Mysteries

As we leave the dark of Winter, astronomers still struggle to understand dark matter and dark energy. We have some understanding of dark matter since we can see its effect indirectly. But we still haven’t observed dark matter particles. Axions are a popular dark matter candidate, but searches for the hypothetical particle have always failed. A new study argues that our searches may have failed because we’re looking for particles of the wrong mass. As for dark energy, we know even less, as it is seen only through the accelerating expansion of the cosmos. One paper published this past month argues that dark matter doesn’t really exist, but is instead an illusion caused by our assumption that Einstein’s theory is right.

On the Radio

Radio astronomy has been rather active recently. One study has been looking at odd circular radio objects in the sky known as Odd Radio Circles. It’s not a creative name, but radio astronomers have been very creative in capturing the highest resolution image of an Odd Radio Circle. It shows ring details we’ve never seen before and narrows down the options of what they could be.

Radio astronomers have also been using a technique known as astronomical radar. This involves beaming radio signals at an object and studying the signals that bounce back. They’ve used the technique to create detailed maps of Mercury, and have even discovered ice hiding in the shadowed craters of Mercury’s poles.

Quiet Sun

In the 1600s there was a 70-year period where the Sun was particularly quiet, with almost no sunspots. It’s now known as the Maunder minimum, and astronomers have long wondered as to its cause. This month a team of astronomers published data on the starspot cycles of several stars, and have found similar patterns. One star in particular appears to be going through its own Maunder minimum. This could help us understand why the Sun occasionally goes quiet.

Whether your life has been quiet or active, I hope the change of season finds you well, and I’ll be back next month with more astronomy news.