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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
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