Gary Ladd explains the science of measuring the cosmos

Community members enjoy Gary Ladd's lecture and fine weather at Grandview Overlook in Page on Sept. 16.

Local author and photographer Gary Ladd gave a presentation at the Grandview Overlook in Page on Sept. 16 about the universe, telescopes, stars, galaxies and other celestial bodies. He reminded audience members that every time they look at the heavens, they are seeing light that has reached the Earth only at that moment, sometimes billions of years after the light started its journey across space. 

The presentation occurred during the Canyon Club of Page’s monthly meeting, on a perfect evening in which there was not even a whisper of wind. As the sun set, it cast a golden glow on Lake Powell, demonstrating what a great vantage point the overlook – a project of the Canyon Club that was completed last year – is for the City of Page.

During his presentation, Ladd explained that radio waves from the Earth travel outward at the speed of light. Since radio signals have only been in existence for around 100 years, they have only been travelling outward for a century or so and are still racing across our home galaxy, the Milky Way. Perhaps one day, some distant planet will receive a signal telling people about Earth news, “The Price is Right” game show, a few bars from a Beatles song, or other things considered important to earthlings.

Ladd talked about the giant telescopes that are being planned from now to the end of the 2020s. There are four such telescopes, the largest of which is expected to be 130 feet in diameter and constructed in Chile around 2024. The larger the telescope, the farther back in time astronomers can peer in time and space.  

The job of an astronomer involves long nights. Ladd told the audience that some of the larger telescope facilities actually organize a “midnight lunch” so astronomers can take a break and have a catered meal. Smaller installations have a lower budget, and astronomers bring a sack lunch.

The universe contains far more stars than astronomers can currently see. According to Ladd, earthlings can see only a very small part of our own Milky Way galaxy. Some stars are giant, but most of the stars we see are small. Our sun is considered a small star, and the light and heat that warm us when we are swimming and boating on Lake Powell are only about eight minutes old.

Giant stars burn brightly and then collapse spectacularly, often with a supernova, and become either a neutron star or black hole, depending on their size. Large stars don’t live as long as small stars.

“They live fast and die young,” Ladd said.

Smaller stars, as they reach the end of their lives, “die” less spectacularly and live far longer. Our sun is considered a small star, yet it is so big that two of our moon’s orbits can fit inside the solar sphere. According to Ladd, our sun burns 70 million tons of hydrogen per second, and there is still plenty of hydrogen to burn for a long time.  

Ladd explained how astronomers estimate how far away stars and other celestial bodies are. The technique of using parallax was discovered in the 19th century and uses closer stars of known distance to calculate how far another star is by the shift seen when viewed from two different vantage points.

A more recent way to calculate these enormous distances includes the Doppler shift seen from stars and galaxies by a phenomenon called redshift. The amount of redshift increases the farther away the star or galaxy is, allowing astronomers another way to measure how far “far away” is.

Galaxies are a collection of stars that each contain hundreds of billions of stars. The cosmos contains countless galaxies, and as scientists build larger telescopes, they can see farther into the universe.

Despite there being so many stars and galaxies, even after 50 years of “listening” to the cosmos for evidence of extraterrestrial life, scientists have not found definitive evidence of intelligent life beyond Earth. But they’re still listening.

With so many other stars out there, it seems surprising that Earth might be the only planet with living beings. Ladd said that perhaps 50 years isn’t long enough to listen, since the distances are so great. Another possibility might be that aliens are smarter than us.

Ladd ended his talk with a quote by Bill Watterson, cartoonist of “Calvin and Hobbes,” who said, “The surest sign that intelligent life exists elsewhere in the universe is that it has never tried to contact us.”

 According to the Canyon Club of Page website, “the purpose of the Canyon Club is to actively pursue improvements to the community in which we live. Through our involvement in our community we will create an atmosphere where local citizens can participate in activities that will enrich their lives and the lives of those living in this community.” The Canyon Club is a non-profit organization. Those interested in joining or attending the monthly presentations should contact the Canyon Club at [email protected] 


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