Heat of the Night

2 June 2022

The first day of Summer approaches, but the warm days have already arrived. In western NY that means making the Great Decision of when to switch from fans to AC. So far I’ve been holding off on the switch.

Scaling Mount Improbable

The search for extraterrestrial life is always a popular topic in astronomy. We still haven’t found any evidence of alien life, but we have been learning quite a bit about how it might appear and survive. For example, one study looked at planets orbiting close to their star. Most potentially habitable planets orbit close to a red dwarf, and it has long been thought that these worlds could be tidally locked, meaning that one side of the planet continually faces its star. But new research has shown that might not be true, and it uses Venus as an example. It turns out that the thick atmosphere of Venus prevents the planet from locking its rotation in sync with its orbit. Exoplanets with a thick atmosphere could also avoid tidal locking, which is good news for potential life.

But not all news is good. Many potentially habitable worlds are part of binary or multiple star systems. We’ve found many cases in which planets can form stable orbits around multiple stars, but the real question is for how long these orbits can be stable. It turns out the answer is complicated. A multiple star system can be meta-stable, where they decay on a time scale just a bit too short for life to truly evolve.

But for planets that do evolve life, how advanced might their civilizations become? One measurement often used is known as the Kardashev scale, which categorizes civilizations into three types (planetary, solar system, and galaxy). The first level, Type 1, controls the energy resources of an entire planet. Based on new research, we are currently at a level of about 0.73, and if we don’t destroy ourselves we’re on track to reach level 1 around 2371. So reduce, reuse, recycle.

At the End

While some research has focused on the beginning, other studies have looked to the end. Specifically the death of stars. Our Sun is expected to die in about 5 billion years, and we’ve long known it will end by becoming a red giant before it settles down to a white dwarf. But the details of this transition are still a bit fuzzy. Recently a study looked at a type of dying star known as an Asymptomatic Giant Branch star or AGB. It found that rather than a simple transition to a red giant, the AGB casts off its outer layers in rings, showing oscillating periods of expansion and contraction. It seems the end of our Sun could be more turbulent than we thought.

Of course, larger dying stars can collapse to become black holes. One interesting recent study showed that the magnetic fields around black holes can actually flip, similar to the way the Earth’s magnetic field has flipped from time to time. We still don’t know just how a black hole’s magnetic field can flip, but it’s fascinating that it can.

Taking a Crack at Things

Finally, many of you have likely noticed a drop off in the number of posts over the past couple of months. There are a couple of reasons for that. The first is that I have been spending most of my free writing time on a fiction novel, the first draft of which is now finished. It will be a while before I let anyone read it. The second is that in May I broke my ankle. All is healing well, but between giving it time to heal and hobbling to do my regular chores my writing output has slowed a bit. But there will be more science posts to come.

Until next time, I hope your days are injury free, and you can enjoy the new season until the next newsletter finds you well.