February 19, 2023

Mid-February at 7:30 PM looking southwest

Sunday, February 19, 2023

Yesterday, February 18, marked the second anniversary of the Perseverance rover's landing in Jezero Crater on Mars. The launch and landing happened in the middle of the pandemic. The four science objectives of the Perseverance mission are: 

  1. Identify past environments capable of supporting microbial life (it has found that); 
  2. Seek signs of possible past microbial life in those environments, particularly in special rocks known to preserve signs of life over time (it has looked but not found biosignatures…yet); 
  3. Collect core rock and “soil” samples and store them on the Martian surface (it has collected 18 of the 38 possible samples so far and deposited 10 on the surface that will be returned to Earth in the 2030s); and 
  4. Test oxygen production from the Martian surface (it has successfully produced oxygen with the MOXIE instrument).

In addition, Perseverance has used ground penetrating radar to study the underground rock layers and shared the limelight with the Ingenuity helicopter which continues to operate LONG after its primary technology demonstration goal was accomplished almost two years ago. The Perseverance and Ingenuity teams have been learning a lot about how to use aerial reconnaissance to enhance the operations of a rover on Mars. Future rovers will undoubtedly all include at least one helicopter/drone.

The Curiosity rover is still working in Gale Crater over ten years after it landed. The most recent finding from Curiosity is that it found the clearest evidence yet of ancient water ripples that formed within lakes in rocks that were thought to have formed when Mars had pretty much dried out. As Curiosity climbs the central mountain, Mount Sharp, it is studying and sampling newer and newer layers, giving us a much better idea of how Mars changed through the past billions of years.

Near the rocks with the rippled patterns are rocks made of layers that are regular in their spacing and thickness. These rhythmic patterns could be from climate changes that happened at periodic intervals like we've seen happen on Earth's deep past. Although the overall trend of Mars' history was to go from wet to dry, the various features seen by Curiosity show that the process was just as complex as what we have found on Earth.

From a vantage point of 98.2 million miles, Mars doesn't have quite the same level of detail and  it appears as the bright orange-red “star” next to the upper horn of Taurus. It is still brighter than any other star in Taurus but it's no longer brighter than the brightest stars of neighboring Auriga and Orion. 

Jupiter and Venus continue to draw near each other. They'll be at conjunction on March 1 in between the dim stars of Pisces and the medium-bright stars of Cetus. Earlier this year we found a dozen more moons for Jupiter, so Jupiter could reclaim top honors for having the most moons of any of the planets. These newly discovered moons are small (just a few miles across) and far out taking over 300 days to orbit Jupiter. 

Our moon is at new phase today, so look for a beautiful thin waxing crescent moon low in the western sky in a couple of nights. On February 21 it will be below Venus and the next evening it will be right next to Jupiter. On February 26, it will be at first quarter phase next to the Pleiades in Taurus and the following night will find it right next to Mars.

Looking at the much bigger picture, astronomers who study the entire universe as a whole (cosmologists) have found that the universe is not as clumpy as it should be—there should be twice as many big galaxy clusters than what we see. The oldest light we can see is the Cosmic Microwave Background (CMB) coming from a time when the universe was just 380,000 years old. The CMB has a bunch of lumps in it that tell us A LOT about the structure of the universe and it's those lumps that eventually formed the galaxy clusters we see today. 

More than 150 cosmologists using the huge galaxy survey called the Dark Energy Survey and the South Pole Telescope have examined hundreds of millions of galaxies and distortions in the light from very distant galaxies by the gravity of nearer galaxies to map out the distribution of matter over the past 8 to 9 billion years. 

Does this mean the Big Bang Theory and our understanding of how the universe developed over billions of years are wrong? No. We are able to explain a lot of the things we see very well. We have many of the broad brush strokes correct and we're now working on the finer details. Now, of course, it is possible that “fixing” a smaller detail could lead to a major revision in the standard cosmology theory but the evidence, even this “smoother by half” study, doesn't support a rejection of the standard theory. It does show that we still have more to learn and with brains hardwired to find pleasure in learning, this study showing something is missing in our understanding of the universe is a good thing!

Evening planetarium shows should resume in March after the Chronos star projector has had some repairs.

Nick Strobel
Director of the William M Thomas Planetarium at Bakersfield College
Author of the award-winning website www.astronomynotes.com