78ºF

The good and bad of satellites

Satellite Picture of Hanna courtesy NOAA
Satellite Picture of Hanna courtesy NOAA

The cover photo above is today’s satellite shot of Tropical Storm Hanna, a familiar picture on TV and a vital tool in forecasting storms of all types, especially tropical storms.

I want to introduce you to another satellite, NASA’s Aqua satellite with MODIS instruments aboard. Our government loves acronyms, don’t they?

MODIS stands for Moderate Resolution Imaging Spectroradiometer, but the bottom line is that this satellite can measure temperatures of cloud tops and that is important in determining how strong thunderstorms are and, ergo how strong tropical systems are becoming. The reasoning is pretty simple: the colder the cloud tops of a thunderstorm, the higher that thunderstorm is growing into the atmosphere; and the higher up it is going, the stronger it is. The stronger storms can help hurricane forecasters determine that a depression is forming. That kind of info led the National Hurricane Center to upgrade the Gulf system to Tropical Depression 8 the other night (along with the invaluable and brave service of the Hurricane Hunters).

Look at the Aqua satellite below and notice the RED colors -- those are very cold cloud tops at -70° and that showed the NHC that Hanna was building strength.

Aqua Satellite Picture shows strong thunderstorm tops (in red) building around what is now Tropical Storm Hanna courtesy NOAA
Aqua Satellite Picture shows strong thunderstorm tops (in red) building around what is now Tropical Storm Hanna courtesy NOAA

So, weather satellites are not just all about pretty TV pictures. They are huge forecasting tools.

So what’s the downside?

More and more satellites are going into space for various reasons (your television entertainment being the least of them!) and we’ve watched launch after launch this year. All well and good until you’re trying to take a fabulous picture of Comet NEOWISE and then look what can happen:

An image of Comet NEOWISE marred by Starlink satellites.
Photo: Daniel López
An image of Comet NEOWISE marred by Starlink satellites. Photo: Daniel López

When watching the skies, the best thing to do is get away from light and that is exactly what Astrophotographer Daniel Lopez did -- he went all the way to Teide National Park on the Canary Islands. And then what happens? SpaceX satellites ruin the perfect comet photo! I had no idea, but SpaceX has already launched 540 satellites to bring high-speed Internet to the world and that’s just the beginning. Elon Musk is planning to send tens of thousands of such satellites into space by next year and that has the astronomy community looking down the wrong end of a telescope. You can read more here.

By the way, Comet NEOWISE will be fading over the next several nights (back in 6,200 years), but two nice meteor showers are on the schedule as Earth passes through ancient comet dust.

Meteor Showers are seen as Earth passes through comet dust credit Earthsky.org
Meteor Showers are seen as Earth passes through comet dust credit Earthsky.org

You can learn more about the Delta Aquarids and the Alpha Capricornids at the American Meteorological Society website right here. Both begin soon and last until early August. You might want to book a flight to the Canary Islands, but then again...

Have a safe weekend and it looks like Hanna stays south of us. Still, keep an umbrella handy!

Frank

Email me and follow me on Facebook!


About the Author: