Climate change is a ticking time-bomb, albeit with a long fuse. The longer that society waits to tackle it, the more difficult to solve it.

A few days before Thanksgiving, the Sentinel-6 satellite was launched from a SpaceX Falcon-9 rocket into orbit. Sentinel-6 is in a series of satellites that have been monitoring ocean rise for the past 20 years. It’s a joint project between NASA, the European Space Agency and other government entities, such as NOAA.

When you think about it, there’s not a lot of ways to make the oceans rise. One effect is ice melt, which at present accounts for only a third of the yearly rise. Another effect is that objects expand as they are heated, and water is no exception. The increase in ocean temperatures account for most of the remaining rise.

Satellite monitoring has shown that oceans are rising in some parts of the world by a rate as fast as 3 millimeters per year. That may not sound like much, but over a period of 20 years, that translates into more than 2 inches of sea level rise. Over 100 years, if the trend continues, that’s nearly a foot higher.

That’s not going to affect us here in Ohio but be careful if you’re planning to buy a vacation home by the ocean. For some locations, such as near the Everglades in Florida or Virginia Beach, ocean rise will have serious consequences.

The technology behind measuring the average ocean rise is very interesting. The basic idea is to send out a radar pulse, wait for it to bounce off the ocean, and measure the time it takes to get back. Then, using the speed of light, convert that time into a distance. Of course, the ocean is not perfectly smooth, and one needs to average out the height of waves and troughs, but that’s not the hard part. How do you get the height of the satellite in the first place?

From Newton’s law of gravity, we know the force (and direction) of gravity to high accuracy at any point in space above the Earth. As taught in a college physics class, the time it takes to complete an orbit can be used to calculate the height of the satellite.

That would be good enough if the Earth was isolated, but the moon also orbits the Earth. The moon tugs ever so slightly on the satellite, and this affects the satellite’s orbit.

In order to get to the desired precision, to measure sea level rise to within a millimeter, it takes a lot of calculations and a deep understanding of orbital dynamics. The payoff is to measure, with certainty, how climate change is affecting our oceans.

https://lasillavacia.com/users/watch-euphoria-special-episode-part-1-online-full-episodes
https://lasillavacia.com/users/watch-euphoria-special-episode-part-1-online-full-episodes