No telescope needed to see 3 planets

  • By Mike Lynch
  • Friday, May 24, 2013 3:41pm
  • Life

I urge you this week to get out in the very early evening, about 45 minutes after sunset, to see the celestial hugging between Jupiter, Venus and Mercury.

Look for the three planets in a tight little triangle just above the horizon.

You have to have an unobstructed treeless view of the west-northwest horizon, but you don’t need a telescope.

They’re within 2 degrees of each other, so close that your thumb extended at arm’s length can pretty much cover up all three worlds. They will slip below the horizon by about 10 p.m.

Venus is the brightest of the three and Jupiter is the farthest away at more than 560 million miles.

The triangle will break up as the week goes on, but all three planets will still be hanging close together. And these three are closer to us than any other stars.

Stellar distances are too cumbersome to express in miles. Light-years do a better job because the numbers are smaller and you’re reminded of just how long it takes for the light from the stars to reach your eyes.

Light travels at the speed of 186,300 miles a second and a light-year is defined as the distance that light travels at that speed in one year.

Given that there’s about 31.5 million seconds in a year, you’ll come up with almost 6 trillion miles for just one light-year.

So if a star is 100 light-years away that star would be about 600 trillion miles away. That also means the light you see from that star took about 100 years to reach your eyes.

How do astronomers know how far away these stars are?

For stars within about 3,000 light-years from Earth, astronomers use the stellar parallax method for determining distance.

Basically a picture of a star is taken when the Earth is on one side of the sun in its orbit, and another picture is taken six months later when the Earth is on the other side of the sun.

If the star is not too distant, you’ll see it shift a tiny bit against the background stars. The shifting of the star against the background stars creates what’s called a parallax angle.

You can calculate a star’s distance using simple geometry that states opposite angles are equal plus some simple trigonometry.

The practice of measuring that parallax angle is very difficult and you’re also making assumptions: You’re assuming that the background stars you are using to measure the angle are stationary. In reality they may be shifting as well.

The Hipparcos satellite was launched in 1989 to measure the stellar parallax and distances to hundreds of stars, but the satellite’s accuracy falls off with smaller parallax angles and larger stellar distances past about 500 light-years.

Stars beyond that require another method, the Hertzsprung-Russell diagram, developed in the early 1900s by Ejnar Hertzsprung of Holland and Henry Norris Russell of the United States.

For really distant stars, Cephied variable stars are used, a huge discovery made by Henrietta Leavitt early in the last century at Harvard University.

The famous astronomer Edwin Hubble used observations of Cepheid variable stars in what was then known as the Andromeda Nebulae to determine that Andromeda was a whole other galaxy, more than 2 million light-years away. Until then, our Milky Way was thought to be the only galaxy in the universe.

Mike Lynch is an astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and is author of “Stars, a Month by Month Tour of the Constellations.” www.lynchandthestars.com.

The Everett Astronomical Society: www.everettastro.org/.

Talk to us

> Give us your news tips.

> Send us a letter to the editor.

> More Herald contact information.

More in Life

Brandon Hailey of Cytrus, center, plays the saxophone during a headlining show at Madam Lou’s on Friday, Dec. 29, 2023 in Seattle, Washington. (Olivia Vanni / The Herald)
Lynnwood-based funk octet Cytrus has the juice

Resilience and brotherhood take center stage with ‘friends-first’ band.

FILE - In this April 11, 2014 file photo, Neko Case performs at the Coachella Music and Arts Festival in Indio, Calif. Fire investigators are looking for the cause of a fire on Monday, Sept. 18, 2017, that heavily damaged Case’s 225-year-old Vermont home. There were no injuries, though a barn was destroyed. It took firefighters two hours to extinguish the blaze. (Photo by Scott Roth/Invision/AP, File)
Music, theater and more: What’s happening in Snohomish County

Singer-songwriter Neko Case, an indie music icon from Tacoma, performs Sunday in Edmonds.

Sarah Jean Muncey-Gordon puts on some BITCHSTIX lip oil at Bandbox Beauty Supply on Tuesday, Jan. 9, 2024, in Langley, Washington. (Ryan Berry / The Herald)
Bandbox Beauty was made for Whidbey Island locals, by an island local

Founder Sarah Muncey-Gordon said Langley is in a renaissance, and she’s proud to be a part of it.

Dominic Arizona Bonuccelli
Tangier’s market boasts piles of fruits, veggies, and olives, countless varieties of bread, and nonperishables, like clothing and electronics.
Rick Steves on the cultural kaleidoscope of Tangier in Morocco

Walking through the city, I think to myself, “How could anyone be in southern Spain — so close — and not hop over to experience this wonderland?”

Byrds co-founder Roger McGuinn, seen here in 2013, will perform April 20 in Edmonds. (Associated Press)
Music, theater and more: What’s happening in Snohomish County

R0ck ‘n’ Roll Hall of Famer Roger McGuinn, frontman of The Byrds, plans a gig in Edmonds in April.

Mother giving in to the manipulation her daughter fake crying for candy
Can children be bribed into good behavior?

Only in the short term. What we want to do is promote good habits over the course of the child’s life.

Speech Bubble Puzzle and Discussion
When conflict flares, keep calm and stand your ground

Most adults don’t like dissension. They avoid it, try to get around it, under it, or over it.

The colorful Nyhavn neighborhood is the place to moor on a sunny day in Copenhagen. (Cameron Hewitt)
Rick Steves: Embrace hygge and save cash in Copenhagen

Where else would Hans Christian Andersen, a mermaid statue and lovingly decorated open-face sandwiches be the icons of a major capital?

Last Call is a festured artist at the 2024 DeMiero Jazz Festival: in Edmonds. (Photo provided by DeMiero Jazz Festival)
Music, theater and more: What’s happening in Snohomish County

Jazz ensemble Last Call is one of the featured artists at the DeMiero Jazz Festival on March 7-9 in Edmonds.

Kim Helleren
Local children’s author to read at Edmonds Bookshop

Kim Helleren will read from one of her books for kids at the next monthly Story Time at Edmonds Bookshop on March 29.

Chris Elliott
Lyft surprises traveler with a $150 cleaning charge

Jared Hakimi finds a $150 charge on his credit card after a Lyft ride. Is that allowed? And will the charge stick?

Inside Elle Marie Hair Studio in Smokey Point. (Provided by Acacia Delzer)
The best hair salon in Snohomish County

You voted, we tallied. Here are the results.

Support local journalism

If you value local news, make a gift now to support the trusted journalism you get in The Daily Herald. Donations processed in this system are not tax deductible.