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Foucault's Pendulum demonstrates the rotation of planet Earth! As the pendulum swings back and forth, the Earth rotates underneath it, causing it to appear to precess around in a circle. The pendulum does a full precession once approximately every 44 hours from our location in Costa Mesa. 
Summer is finally in full swing here in the northern hemisphere now that we're past the June 20th solstice. From now until December 21st the sun will rise progressively later and setting progressively earlier every day, so enjoy the sunshine while it lasts!

This weekend will be your ideal chance to see the elusive planet Mercury as it nears its maximum western elongation, that is, its greatest separation westward from the Sun. It'll be visible just before sunrise low on the Eastern horizon. Its a tough one to spot in the dawn light, so you might need to grab a pair of binoculars!
The stars and constellations steadily march westward every night, causing us to lose some favorites like Leo by the end of the month, but replacing them with some of our early Fall constellations like Pegasus over in the East. By the time August rolls around we will also have both Jupiter and Saturn shining brightly in our early evening sky, coming out of the South-east just after sunset. 

Scorpius, Sagittarius, and the Summer Triangle will all be in their peak positions this month, so make sure to grab your favorite sky app to be able to identify them!

Other things to look out for include July's full "Buck" Moon on July 24th, and the Delta Aquariid meteor shower that peaks in the early evening of July 29th. 

Q: Would the earth fit inside Pluto? Moana, age 6, Costa Mesa

A: Pluto is much smaller than any other planet in our solar system. Even our moon would be too big to fit inside Pluto! In fact, if you rolled Pluto out flat, it would only have slightly more surface area than Russia. So, the short answer is no, the Earth would not fit inside Pluto. But what if we tried anyway? 
It turns out the science concerning what happens when you squeeze a planet's worth of rock and metal into a space less than 1% its former volume is not very well established. What we can say is that if we squeezed all 6*1024 kg of the Earth's mass into the volume of Pluto it would get pretty crazy. Our new travel-sized Earth would be very dense. A tennis ball-sized chunk of it would be about 135 kg or just shy of 300 pounds. Fortunately we'd still be a way off from creating a Black Hole, but we still have a lot of gravity to contend with. 
The force of gravity increases the closer you get to something, so now that we've packed Earth into a much smaller space we can get closer to it. The surface gravity would be approximately 28.7g, or 28.7 times normal Earth gravity, so a person weighing 150 pounds normally would now weigh over 4300 pounds. For comparison, Jupiter's gravity is only 2.5g, and we are just barely beating the Sun's 28.02g. 
This would be very interesting for a very brief moment before everything exploded. The thing about compressing any material like this is that it tends to get very very hot, and with this much pressure we are looking at temperatures likely to exceed those at the surface of the Sun. The rock and metal that make up our planet will quickly liquify, vaporize, and likely turn into a plasma. Then it would explode. We don't have enough gravity to maintain our compact Earth, so it won't stay compact for much more than a fraction of a second before it went from a very hot ball of metal to a very large cloud of rapidly cooling gas. Essentially a tiny supernova. 
If Moana is really set on making this happen, I'd suggest trying it with Mars first. 

Q: Recently the Airforce has released camera video footage of UFOs from military planes. That was a surprise since that stuffed was classified for decades. Might we expect similar images from astronomers telescopes, also classified until now, of UFO sightings to “finally” be released to the public? Also, why this change after all these decades of secrecy (since July 8, 1947)? Dennis, age 73, San Clemente

A: I'll start out by saying that none of the declassified footage I've seen so far has made me jump to the conclusion that they are extraterrestrial visitors. The reason for the declassification comes from Congress demanding it, mostly at the behest of their constituents. UFO's are Unidentified Flying Objects, and to get away from the association with little green men, the US military has also started using the term Unidentified Aerial Phenomena or UAP's. In both of these, unidentified is the operative term. All we know with any degree of certainty is that someone thought they saw a "thing" that may or may not have been moving "strangely" or that there is a spot picked up by a camera somewhere. If you've ever enjoyed a book of optical illusions you know how easy it is to trick the human eye and brain into seeing something that isn't there, so the urge to jump straight to alien visitors, while fun to think about, is definitely premature. 
This leads into the reasons we don't have reports of UFO's by actual respected astronomers. Unless they are specifically working for the government nothing they find would be classified, and plenty of astronomers spend their careers with institutions like SETI, who's whole purpose is to find evidence of alien life. If they found any actual credible evidence they would be singing it from the rooftops (watch the movie 'Contact' to see how something like this would likely play out). Scientists in any field tend to have a much higher bar for what they consider good evidence, and when they think they have it the first thing they do is invite as many other scientists as possible to prove them wrong. This happens pretty frequently. You might hear on the news about some exciting discovery that *might* be an alien megastructure around a distant star, but you likely won't see the follow up a week later that says "yeah, that was actually just a cloud of debris." 
I don't want to discourage the people who romanticize interstellar visitors. I started out my whole career with a love of science fiction and a curiosity about what's "out there." Based solely on statistics I believe there is very likely life somewhere else in  the universe, but the scientific community is going to need a lot more than a blurry video to definitively answer what is quite possibly the biggest question in existence. 
For more, check out this great article in Scientific American


with Scott Mitchell

Have questions about the universe and how it works? Each month Planetarium Director Scott Mitchell will answer questions submitted by our readers both young and old!
Ask Here!
  • Venus is the hottest planet in the solar system. It's thick Carbon-Dioxide atmosphere traps the Sun's heat bringing the surface temperature up to 464°C or 867°F. Enough to melt Lead!
  • Venus' thick atmosphere also contains high levels of sulfuric acid which rains down onto the surface. 
  • Lots of atmosphere means lots of pressure! The air pressure on the surface of Venus can get up to 93 bar (1,350 psi) which is roughly the same pressure you'd experience by diving 900 meters (3,000 ft) underwater on Earth!
  • The only successful landings on Venus were conducted as part of the Soviet Union's Venera program in the 1970s and 80s. Several spacecraft were able to touch down and contact Earth, but none of them lasted more than a couple hours before succumbing to the intense heat, pressure, and literal acid falling from the sky.
  • The astronomer Galileo showed with his telescope that Venus goes through phases much like the moon does. He used this to help prove that Venus and all the other planets revolve around the Sun, and not the Earth.
  • In the future humans might be able to live in balloon cities floating in the Venusian clouds where the temperature and pressure aren't so deadly. Just be careful not to drop anything over the side!

Mission Updates

By Scott Mitchell
We received exciting news this month from NASA about two new missions that will explore our sister planet, Venus. It is theorized that billions of years ago, Venus may have been a lot more like the Earth, with oceans of liquid water and none of that awful hellscape that is there today. Studying how Venus developed might also give us important insight into how our own planet is changing, and what we might do to reverse climate change at home or what to avoid in the future. 
Tho this end NASA has selected two missions to be part of the Discovery Program that began back in 1992. These missions are The ​Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging (DAVINCI+), and Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy (VERITAS). 
DAVINCI+ is a surface mission, where a lander will parachute down to the surface for the first time since the Soviet Union's Venera 14 in 1982. It will sample Venus' atmosphere, and analyze the surface to determine if Venus ever had an ocean. 
VERITAS is an orbiter mission that will take detailed radar maps of the Venusian surface so that we can better understand its geologic history and determine whether or not Venus has active geologic processes like plate tectonics and volcanism. 

Both missions are planned to launch somewhere between 2028 and 2030. 

A Message From the Director

By Scott Mitchell
We are very excited to announce the Planetarium will be reopening to the public on August 2nd with minimal capacity restrictions! We will return to offering public shows Friday nights at 7:00, and Saturday and Sunday afternoons at 12:30 and 2:00. We will be kicking off our reopening with two brand new programs: We are Stars (narrated by Andy Serkis) and Dynamic Earth (narrated by Liam Neeson).
We will also be reopening in-person field trips this fall, so if you have a class anywhere from Kindergarten through High school, check out how to visit us here!

Explore the night sky past, present and future with one of the same tools we use in the planetarium!
Travel all around the solar system to visit strange new worlds!
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