Veronika Asks...Mr. Greenberg About The Universe

Veronika Valia

What would happen if you fell into a black hole? Mr. Greenberg explains how this process is actually called spaghettification. Interesting. And delicious?

Ah, the Universe. So big, so vast, and so...comforting? Yes. Comforting. I mean think about it. We’re just a tiny speck on a huge, over-populated, dying-due-to-global-warming piece of flying rock. One of many, many big, strange flying rocks in our solar system, which is just one of many thousands in our galaxy, of which there are many more in our Universe. 

And perhaps there are even more Universes? 

I mean, in the end, who cares right? Who cares about your mid-semester Amstud grade, or if you had a piece of food wedged in between your teeth while talking to your crush. We’re all specks, which makes tests, relationships, and our brains even smaller in importance, right? 

How big is the Universe truly? Are there things we have yet to discover that may make our existence more meaningful? What are the great mysteries of the Universe we may never understand? I wanted to dig into that, and so I decided to speak with Mr. Greenberg, Lovett’s resident astronomy and physics teacher. So here we go. Let’s do this.

I decided to start with something my fellow newspaper companions came up with. Something, although it may seem simple, not many people know about. Pluto. What is it? Is it a planet? I mean things have changed a huge amount since we left kindergarten, and most of us don’t dive into astronomy past elementary school. Well, here’s your answer.  “Yes, Pluto is a planet,” starts Mr. Greenberg amidst a chuckle. “But it’s a different kind of planet. When Pluto was first discovered it was so far away that the telescopes of the time couldn’t distinguish any of its features, and couldn’t recognize any objects beyond Pluto,” As telescope technology gets better and better things beyond Pluto end up getting discovered. “Then the question is,” he says, “what are these other objects? Are they planets?” Yes, they are, he explains, but they are a different type of planet. 

For example, they’re different from the terrestrial planets, Mercury, Venus, Earth and Mars. He further explains how those have hard, metal cores and there are rocks on the surface. There is also another group of planets that we commonly refer to as gas giants. Pluto is neither. Instead, it is part of another group of planets, and it turns out there are a lot of objects that fall into this category. “Now, they are commonly referred to as dwarf planets,” Mr. Greenberg explains. But are they all the same? No. They have varying characteristics, as different regions of our solar system developed very differently based on varying early conditions. These varying dwarf planets are also called Kuiperbelt objects, because that’s the region of the solar system that they’re found in, and they are also called trans-Neptunian planets, because they’re outside of Neptune’s orbit.

And what about black holes? I mean, they’re one of the other very mysterious objects of the Universe that we know hardly anything about, a step up from Pluto. Let’s dive into it. I mean, what’s inside a black hole? “We don’t know,” Mr. Greenberg starts. “The very nature of a black hole, is that information cannot escape from it. We have no idea what's inside of it, and it's one of the few areas of the universe that we are unable to explain physically.” Physically? I asked him to break this down for us. “There are two theories that apply most commonly in space: quantum mechanics, which explains things on a really small scale, and general relativity which explains things on a very large scale.” He explains how “black holes are really massive but also really really tiny at the center, and if you try to explain them using both of those theories it breaks down mathematically.” Because of that, what the math shows, no one knows what’s inside of one and we don’t have a theory in science that allows us to explain that kind of phenomenon.

However, what would happen if you fell into a black hole? “Because the gravitational force in a black hole is so immense, things get stretched out, and because the force on each end of the object is so different, things get pulled apart almost like toothpaste getting extruded from the tube.” Mr. Greenberg explains how this process is actually called spaghettification. Interesting. And delicious?

One strange theory (hey, it may not even be that strange) is that perhaps there's a different Universe inside of a black hole. Maybe a world in which the sky is white, like a ying and yang type scenario. I mean who knows, but I wanted to ask Mr. Greenberg about this. What is the idea of a multiverse? Does it even exist? I mean, we’ve all seen the concept in science fiction movies like Interstellar, but does the concept have any basis in reality? First, he explains what it is from a scientific perspective. He starts by saying that “it is an idea that for every situation, there are an infinite number of possibilities and there are universes when all of those things are all happening.” For example, let's say you’re at Chick-fil-A and don’t know what to order, there are Universes where every option (let's suppose they’re infinite) is happening, and then because of that decision, a different world plays out because of your decision. However, as fascinating a concept as this is, Mr. Greenberg says that “in science, something either needs to be experimental in nature or observational in nature. However, there are a number of theories of different dimensions and things of that nature, but if we can’t see it or observe it or do any experiments on it, I would debate whether or not we call that science at this point.”

But hey, although your dreams of the multiverse may be crushed, the second best thing to blow your mind is time. Have you ever heard that it takes 8 minutes for the light from the Sun to arrive on Earth and so the light you’re looking at is the light from 8 minutes ago, and as Mr. Newman mind-blowingly pointed out, that means since light takes a fraction of a fraction of a second to travel across a room, you’re seeing your classmates in the past. 

However, is this completely true? Does it even matter? Is it truly that mind-blowing? Does that mean if someone is already dead, you see them 7 minutes in advance? Well, according to Mr. Greenberg, “the sun is 96 million miles away and so on the surface of the Earth, the amount of time it takes one object to travel to another is insignificant in terms of our perception, but as we start talking about distances in space, from the sun to the Earth it takes 8 minutes, from other stars to earth outside of solar system we’re starting to talk about years.” That could mean when we stargaze, we’ve been seeing the light from a dead star. 

Hey, some of the parts of our favorite constellations may not even fully exist. “When we look at things outside our galaxy we're talking about hundreds of thousands of years,” Mr. Greenberg says, “and so we can detect light that has been traveling for billions of years and close to the formation of the solar system.  And when we talk about the solar system we’re talking about the parts that we can see. There are areas of the solar system of the universe that have spread out farther than it would take the light to get to the earth, so we talk about the observable universe, as there are parts of the universe that we can’t see because the light hasn’t made it to us yet.” That’s wild. Given current technology, we won’t even be able to explore that far out.

But what does that mean for time travel? Time is just a made-up thing right? According to Mr. Greenberg “the way that we tell time sort of, maybe, is a little contrived, but there are ways that one could----I’m not sure how to best answer that.” Oh, no. But he went on, saying that “there are things that are physically possible and things that violate laws of nature. There are some things, as far as we know right now, based on the way the universe works, couldn’t happen, like traveling faster than the speed of light, and that’s a physical impossibility.” Why? I asked. He responds saying that “the only thing that can travel that speed is light which is a massless thing, anything that has mass can get close to the speed of light, but can’t get there.” To even further blow our minds, “when you’re traveling at the speed of light, time stops. Time actually doesn’t elapse when you're at the speed of light.” 

In addition, time is not experienced the same way by everyone. For objects that are moving quickly, time doesn’t elapse the same way for objects that are moving very slowly. Where does this come from? According to Mr. Greenberg, there are experiments that have verified this. This is Einstein's theory of special relativity that time doesn’t elapse the same way with really massive objects and really small objects. Gravity affects time. And so we observe time in different ways, however since we are all, relatively around the same mass, weight or force due to gravity is going to be very similar, and so, although time is a social construct, all humans experience time in a very similar way.

However, back to the meat of this hamburger: time travel. According to Mr. Greenberg, without directly manipulating time, “There are ways that you could travel through space, with things such as wormholes. Wormholes are ways that one region of space has been bent to connect to another region of space, and there isn’t anything that says that that isn’t possible mathematically, but that isn’t something that has been observed or something we currently understand to make happen. But it's a common thing in science fiction movies to travel great distances that come with bending space.”

Okay, I swear this wasn’t my question. But hey, why not take a stab at it anyway. Without too much fluff, let’s cut to the chase here. Is there any chance that the Earth is flat? As I figured he would, Mr. Greenberg shuts that down immediately. “There is no chance that the Earth is flat,” he says. “There’s an abundance of evidence and experiments that show that the Earth is round, and to say or believe the Earth is flat is to believe something that is clearly refuted by observation, experiment and evidence, and [when you discuss if the Earth is flat] you’re no longer having a scientific discussion, and personally I would choose not to engage in such a discussion.” Damn. Let’s go Greenberg. “Certainly people are entitled to believe what they want, but that doesn’t mean that their belief is reasonable, or there's any evidence to support that.”

However, he’s not done yet. “I don’t know how many people sincerely believe the theory as I don’t have discussions with flat Earthers, so ultimately I don’t know, but it's a centuries-old belief, and you learn in elementary school that people didn’t want Columbus to sail across the ocean blue because they thought he’d fall off the Earth, but even at that time it was pretty well understood that that's not how it was.” Even then. “I mean you can clearly see ships coming onto the horizon, for example, you can’t see them and then you can see them, which from the most basic observations hundreds of years ago, show that the Earth is round.” To end off, he says that “it’s a belief that people had hundreds if not years ago, and to me it's sad. It limits your ability to understand the universe in the way that it is and we can’t choose what it is, it is what it is and you like it or not.”

Mr. Newman wanted me to ask Mr. Greenberg about the "trash corona" around Earth. Mr. Greenberg explains that it’s a growing problem. “As more countries are putting objects up into space, it's a potentially a dangerous problem for the international space station, because space debris is moving tens of thousands of miles per hour so if a piece of space debris hits the space station it could be catastrophic.” But what does he mean by catastrophic? Could it create a black hole? Cause a break in the space-time continuum? No. But, “it could cause a hole in the space station, and the station would lose pressure, I mean a large enough thing hits the space station, it could be the end of the space station. Over a certain size all space debris is actually tracked, and while smaller pieces are going to burn up upon re-entry into the earth's atmosphere, most bigger pieces are probably going to end up in the ocean, probability wise, but bigger pieces could hit the earth and cause damage to infrastructure and even kill people on the surface of the earth.” He ends saying that he thinks “space exploration is definitely our future and we need to be very careful about space debris and what that is going to do to the Earth and our ability to navigate that region.”

Now our last and final question. What about life on other planets? According to Mr. Greenberg, “I think it is likely but I don’t know about the likelihood of intelligent life, but in terms of microbial life, I think we'll find it in our own solar system, if not on subsurface waters of Mars, we'll find it on some of the moons of Jupiter and Saturn.” He explains that this is because on those bodies “there are conditions that are prime for microbial life. There are liquid environments, and from what we know so far, things that are necessary for life are some kind of liquid medium, water usually, and some kind of energy or heat source. Geothermal vents at the bottom of the ocean we’ve seen life develop there, there are geothermal vents like that on moons of Saturn and Jupiter and subsurface oceans on other bodies.” In short, “I would be very surprised if there isn’t life in our solar system,” he says.

But could there be intelligent life outside our solar system? Or a parallel universe where it’s us but slightly different? Maybe when you smile into a mirror it winks back at you? Mr. Greenberg puts it this way: there are hundreds of billions of galaxies and each of those has hundreds of billions of stars, and very likely that intelligent life has developed elsewhere, but given current technologies will we ever know? “There are mathematics and theories that suggest that's possible, but again you can’t observe it, it's just a lot of fancy math.” 

Ooh. Perhaps they have the same problem and they’re just trying to find us.

The Lovett School is an independent, coeducational day school where children from Kindergarten through Grade 12 find the courage to explore and the drive to discover.

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