Last week, I talked about the extremes of Antarctica. Parts of the continent at the bottom of the world in the Southern Hemisphere have already reported temperatures below minus-100 degrees Fahrenheit and their winter season officially began today.

One of the topics I teach in my Physical Geography course at North Idaho College is the Earth’s history and extinctions based upon the geologic evidence. It’s hard to believe, but geologists say approximately 99 percent of all living species that have inhabited the Earth at one time or another have gone extinct.

I’m always looking for interesting topics that relate to the subjects I teach in class. I came upon an interesting program on the Science Channel called “What on Earth?” This particular segment of the program talked about a huge gravitational anomaly found in Antarctica.

With the addition of satellites over the last 50 years or so, we’ve been able to better predict the weather, warn populations of potential hurricanes, detect changes in our climate and ice fields, observe changes in sea-surface temperatures and so much more. These wonders of technology can see things our eyes are unable to detect.

Among the amazing satellites in space are NASA’s GRACE (Gravity Recovery and Climate Experiment) satellites. On this particular program, one of those satellites detected large anomalies of the Earth’s gravity in southern Antarctica.

Gravity on the Earth is not uniform. Mass from our planet is constantly pulling on the satellites above the Earth. Larger geologic features have more mass, which shows up as a bigger gravitational anomaly. Scientists can then map these differences which are useful for locating minerals, fresh water and other valuable resources.

In that southern section in Antarctica, the satellite detected an abnormally huge gravitational anomaly that raised the eyebrows of many scientists. Some researchers were concerned it was a large volcano underneath the massive amounts of ice, but they determined the Earth’s crust in that part of the world was too thin.

To figure out what was below the mile of ice causing this unusual gravitational anomaly, scientists used a satellite that has ice-penetrating radar to see what’s going on underneath. Thanks to the data from that satellite, scientists concluded the unusual phenomenon may have resulted from what appears to be a large impact crater about the size of Pennsylvania deep within the ice.

Of course, the most famous asteroid impact is the one in the Yucatan Peninsula in Mexico, which many believe ended the dinosaur’s reign on Earth about 65 million years ago. The crater underneath the ice in Antarctica is estimated to be about three times bigger than the one in Mexico.

What is interesting about this crater is the timing. Based on calculations, some scientists estimate this impact in Antarctica may have occurred about 250 million years ago, the time of what many believe was the greatest extinction of species on the planet.

Geologic evidence shows that in Siberia, volcanic lava poured out of the Earth continuously for about 1 million years. It was called “The Great Dying” and resulted in about 90 percent of all land and marine species going extinct. It’s estimated that over 1 million cubic miles of lava poured out, which would cover the United States in more than a half-mile of lava.

This period may have also led to the beginning of the dinosaurs on Earth. The shockwaves from the impact in Antarctica may have induced or contributed to the mass extinction about 250 million years ago. It’s ironic that an enormous impact may have led to the onset of dinosaurs and another impact led them to extinction.

Scientists remind us that large asteroid impacts are part of Earth’s history and it’s not the question of “if” they will occur, but “when.” The good news is that no one sees any of these objects large enough to cause such a cataclysmic event in the near future. `

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In terms of our local weather, summer officially begins at 3:34 p.m. today. It will start feeling like summer for the rest of June as temperatures will be warming into the 80s and even a few 90s as the strong high pressure ridge builds in over the area.

We don’t see much rainfall across the Inland Empire through the rest of the month. In fact, Cliff informed me last week that the desert region of Cairo, Egypt, has received more rain this month than at his station. Cairo has reported 0.67 inches of moisture as of late last week and we’ll likely end up with less for June of 2016.

The next chance of scattered showers and thunderstorms should be during the “new moon” lunar phase of July 4-10. Right now, we don’t see any big storms around the Fourth of July, so have fun and be careful. We still believe that the summer of 2016 should be more “normal” in terms of precipitation, with August possibly being the wettest month.

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Contact Randy Mann at randy@longrangeweather.com