Sunday, April 28, 2019

Idaho Skies Transcript for April 29th and 30th

PAUL
Welcome to Idaho Skies for April 29th and 30th. We’re your hosts, Paul...

RACHEL
...and Rachel.

PAUL
Did you know that you can visit a gravitational wave observatory in Washington?

RACHEL
Many Idaho Sky listeners have visited optical observatories, like the one at Bruneau Dunes. However, unlike an optical observatory, a gravitational wave observatory looks for and measures disturbances in the fabric space-time. So astronomers there aren’t looking through telescopes. 

PAUL
Since gravitational waves distort space and time, their passage causes the distance between objects to shift slightly. The amount of shift is smaller than the diameter of a proton once it reaches Earth. If you recall from school, protons are one of the subatomic particles inside the nucleus of an atom.

RACHEL
So how on Earth do you measure a gravitational wave on Earth? Well, out at the Hanford site in eastern Washington, MIT and CalTech have built a two-mile long interferometer. An interferometer is a device that compares two laser beams to each other. However, the beams have to come from the same laser to make this work.

PAUL
At the Laser Interferometer Gravitational Wave Observatory, the light of a single laser is split into two beams and send down two paths. When a gravitational wave passes through the observatory, the two paths vary in distance very slightly. And by using the process of interferometry, that tiny distance can be measured.    

RACHEL
That’s Idaho Skies for the 29th and 30th of April.

PAUL
Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.
For Idaho Skies this is Paul...

RACHEL
...and Rachel.

PAUL
Dark skies and bright stars.

Monday, April 22, 2019

Idaho Skies Transcript for April 22nd and 23rd

RACHEL
Welcome to Idaho Skies for April 22nd and 23rd. We’re your hosts, Rachel...

PAUL
...and Paul.

RACHEL
Hey stargazers, the Lyrid meteor shower peaks on the night of the 22nd and morning of the 23rd.

PAUL
Listeners wanting to observe the first warm-weather meteor shower of the year will want to see this one. This event occurs on a Monday night and Tuesday morning, which can be a problem for those who work. However, this year the moon is 20 days old and therefore, a large gibbous that will affect meteor viewing once it rises. 

RACHEL
The sky gets dark enough for meteor viewing by 10:00 PM. The radiant for this shower, which is where meteors will appear to originate, also rises by this time. The moon on the other hand will rise by 1:30 AM. This means stargazers will only have between 10:00 PM and 1:30 AM to watch the meteor shower. 

PAUL
So yes, this meteor shower occurs a little late on a Monday night. However, it’s not an event that requires stargazers to stay up past midnight to see. Meteor enthusiasts should search for streaks of light originating from the low northeast. That’s close to the brightest star you’ll see in this part of the sky, Vega.

RACHEL
Under dark conditions, this shower can produce up to 18 meteors per hour. The meteors are only the size of a grain of rice, but traveling at a speed of 29 miles per second. That’s an immense amount of kinetic energy and the reason why they can appear so bright. So enjoy a demonstration of destructive reentry on Monday night. 

PAUL
That’s Idaho Skies for the 22nd and 23rd of April.

RACHEL
Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com

For Idaho Skies this is Rachel...

PAUL
...and Paul.

RACHEL
Dark skies and bright stars.

Sunday, April 14, 2019

Idaho Skies Transcript for April 19th, 20th, and 21st

PAUL
Welcome to Idaho Skies for April 19th, 20th, and 21st. We’re your hosts, Paul...

RACHEL
...and Rachel.

PAUL
Ancient cultures understood that some stars varied in brightness, but it wasn’t until 1783 that an astronomer proposed a mechanism to account for stellar variability.

RACHEL
The astronomer’s name was John Goodricke, and he was born in the Netherlands on September 17th, 1764. A childhood illness left him profoundly deaf, but he didn’t let this prevent him from carrying out astronomical research. Upon his return to England, he took up observing variable stars on the advice of a neighbor.   

PAUL
One of the most famous variable stars is named Algol. In Arabic, its name means the ghoul and people normally refer to it as the demon star. Until Goodricke, no one appears to realize that Algol changed brightness at a regular period. Goodricke’s observations indicated the star maintained constant brightness for 2.9 days.

RACHEL
Then for about 10 hours, Algol becomes about half as bright. Since this period was so regular, Goodricke proposed that Algol consisted of two stars. Goodricke thought the stars orbited each other, and when the fainter star passed in front of the brighter, it caused an eclipse. Astronomers today can detect an even smaller eclipse that occurs when the brighter star eclipses the fainter one.     

PAUL
This variability of Algol is very noticeable to stargazers, even to those living in Boise. To see it yourself, use a star map to show you where to find the constellation of Perseus and its star Algol. Currently, Algol appears in the low northwest after dark. Check out online resources for the times and days that Algol reaches minimum brightness.   

RACHEL
That’s Idaho Skies for the 19th, 20th, and 21st of April.

PAUL
Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.
For Idaho Skies this is Paul...

RACHEL
...and Rachel.

RACHEL
Dark skies and bright stars.

Idaho Skies Transcript for April 17th and 18th

Idaho Skies
17 - 18 April

RACHEL
Welcome to Idaho Skies for April 17th and 18th. We’re your hosts, Rachel...

PAUL
...and Paul.

RACHEL
Albert Einstein passed away on April 18th, 1955.

PAUL
Einstein was a mediocre student, but mostly in classes that he wasn’t interested in. He did well in other subjects, like Mathematics. His first job after graduation was working for the Federal Office for Intellectual Property in Bern, or the Swiss patent office. There he worked as a technician examining patent claims. This job gave him time to work on his passion - physics. 

RACHEL
1905 was an extraordinary year for Einstein. He published papers on the photoelectric effect, Brownian motion, and special relativity. The first two papers described events in the atomic world, while relativity explained the effects of traveling near the speed of light. Einstein was instrumental in the development of quantum mechanics, but he wasn’t happy with the conclusions it eventually reached. 

PAUL
Special relativity, it turns out, is very limited. So Einstein went on to expand it to include gravity and acceleration. The result was the General Theory of Relativity. His general theory taught us that the universe was more amazing then we imagined. And it has led to the discovery of new phenomena and ways to observe the universe.

RACHEL
Black holes were first hypothesized by John Michell in 1783. It wasn’t until Einstein’s General Relativity in 1915, however, that we could actually determine the properties of black holes. Not only that, but we can use the gravity waves Einstein predicted to detect events like colliding black holes.     

PAUL
That’s Idaho Skies for the 17th and 18th of April.

RACHEL
Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com.
For Idaho Skies this is Rachel...

PAUL
...and Paul.

RACHEL
Dark skies and bright stars.

Idaho Skies Transcript for April 15th and 16th

PAUL
Welcome to Idaho Skies for April 15th and 16th. We’re your hosts, Paul...

RACHEL
...and Rachel.

PAUL
Ursa Major is located high overhead during April evenings.

RACHEL
The portion of Ursa Major that most people are familiar with is the Big Dipper. The Big Dipper is an asterism, not a constellation. Asterisms are familiar patterns of stars, rather than official astronomical constellations described by the International Astronomical Union. For our curious listeners, there are 88 recognized constellations.

PAUL
The Big Dipper presents something of a vision test. Look for the second star in its handle, or the star at the bend of the handle. Most people with good vision will see that this star is actually two separate stars. Of course, the brighter the background light and the hazier the sky, the more difficult this becomes. You can impress friends and neighbors by telling them that the bright star is named Mizar and the fainter one is named Alcor. 

RACHEL
Humans have known for a long time about Mizar and Alcor. However, in 1650, Italian astronomer Giovanni Riccioli recorded that Mizar itself was a double star. He needed a telescope to magnify Mizar enough to split it into two separate stars. By the way, we celebrate Giovanni’s birthday on Wednesday the 17th.

PAUL
You can replicate Giovani’s observation of Mizar tonight. Just take your binoculars outside and look up. Your binoculars will show a widely spaced Mizar and Alcor. But look carefully and you’ll see that Mizar is two closely spaced stars. Astronomers have discovered that the two stars of Mizar are actually double stars themselves. So Mizar is actually four stars orbiting each other.           

RACHEL
That’s Idaho Skies for the 15th and 16th of April.

PAUL
Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.
For Idaho Skies this is Paul...

RACHEL
...and Rachel.

PAUL
Dark skies and bright stars.