Hi Cape Elizabeth students,
Here are some answers to a few of your questions and some from other local schools too.
What is the main thing that is stopping nanotechnology from advancing?
Nanotechnology has actually progressed quite a lot since the field began in the 1980s. Nanocomposite materials, which are any solids that have a dimension of less than 100 nanometers (1/1000 the thickness of a sheet of paper), have been becoming useful in many industries. The textile industry has developed nanocomposite materials that make clothing more stain resistant. The transportation industry has been replacing some materials, like the steps to get into trucks, with nanocomposites that overall make the vehicle lighter and more fuel efficient. Other types of nanomaterials help to reinforce car parts, like bumpers, making them stronger. In the electronics and computer industries, nanoparticles have helped make screens more water repellent and anti reflective to reduce glare. Nanoparticles has also helped make computers and cell phones smaller and run faster. Quantum dots, a nano sized semiconductor, has also revolutionized biological imaging.
So nanotechnology has advanced quite a bit, but there is plenty more progress and potential for the usefulness of nanoparticles. The largest challenge to overcome is getting the nanoparticles to form a consistent layer. In 2009, a Nobel prize was awarded to a team who developed a way to make a single layer of particles. The interactions between nanoparticles are hard to control. It is also difficult to pinpoint what is causing the problem due to the small scale and size. In short, we do not know enough about the interaction between nanoparticles to reach their full potential right now and how to use these interactions to create useful devices. However, there has been some great progress so far and there will continue to be amazing breakthroughs as more and more research is done everyday.
-Kara
If you split an atom to create an explosion, where do the two parts of the atom go?
To explain where the parts of the atom go when breaking an atom apart, lets first look at what an atom is made of. You can think of atoms like a ball for now. Hovering inside the ball at the center, there is what is called a nucleus. The nucleus is made up of protons and neutrons and you can think of them as tinier balls packed closely together. On the outsides of the ball there are electrons. Splitting an atom breaks apart the center (the nucleus) into two smaller centers. Kind of like if you had a bunch of skittles melted together and then you broke it into two pieces. These two smaller pieces are atoms themselves.
If you were to weigh the two new atoms, you would think they would add up to the weight of the single atom you started with. When you actually weigh the two atoms though, they weigh a little less than the single atom you started with. This little bit of unaccounted for mass is actually energy. It is that release of energy that is the explosion. The two new atoms are still there but may move away from each other rapidly from the energy release.
-Brian
From Yarmouth - The universe is infinite. The universe is always expanding. How can it be both? (GW, grade 7, Yarmouth)
To understand how something infinite can expand, we need a clear idea of what we mean when we say it expands. To do this, we start with something more familiar than the entire universe; we start with a rubber band.
Imagine a long rubber band, say one that is a whole foot long. Say we try and pull at both ends to stretch it out: we somehow get it to be double the size (it is really, really stretchy). What has changed?
We have already described the first change: it is twice as long. But more is going on. Instead of focusing on the whole thing, let us focus on a small part of it, somewhere in the middle. This small section of it has probably increased in size as well. Another thing has changed, too. The rubber band is now thinner than it was before, because we spread the rubber out.
So where does that leave us then? We can now describe the stretching of the rubber band in three ways, only one of which actually requires looking at the whole rubber band. Even better, knowing that any one of them happened basically tells us that the others did. If we know that all the parts of the rubber band increased in size, then we know that the whole thing did. So just by looking at each part of the rubber band, we can tell that it expanded.
And that’s the trick: when thinking about something infinite, we don’t want to think about the whole thing. That is hard to understand and hard to reason about. Instead we look at what happens in each small section of it. This is called thinking locally versus thinking globally. If we think locally, it is a lot easier to see what we mean when we say that the universe is expanding.
When the universe expands, each little section of it it gets bigger and spreads out, but the whole thing does not get bigger. This might seem like it contradicts with what we said earlier: we said that knowing that each section of the rubber band increased in size tells us that the whole thing increased in size. The difference was that the rubber band is finite, and not infinite.
Infinity does not work like we would expect. It goes against our intuition at every turn. It’s bizarre properties have tripped up countless mathematicians and scientists over the years. When thinking about something as strange as infinity, you have to change your intuition to understand it.
-Oliver and Jacob
What does a black hole look like? Can it be seen? (GW, gr. 7, Yarmouth)
It may be a bit philosophical to say, but what does it actually mean to photograph something? In a camera, the only way you can generate an image is if photons (tiny particles of light) from an object, either reflected or emitted, make their way into the camera's lens, and then onto film or a digital sensor. If no photons from the object make it to the camera, that object will not be in the photo. Black holes are called black holes because their gravitational pull is so strong, even photons traveling at the speed of light cannot escape. As no photons make it out of the black hole, and therefore not able to get to your camera, that would lead you to believe that you cannot take a picture of a black hole, right? But what if you know something is supposed to be there, you take a picture, and there is a big black hole in the photo covering up an object (star or galaxy) you know should be in the photo. What if it only covers part of it and then you see a chunk missing just like the bite out of the apple on the apple logo. That would give you a clue as to the fact that there is something infact there. Further, the gravity a black hole has is so strong, it doesn't just cover up objects you are trying to look at, it bends light around itself and distorts images. This is called gravitational lensing and it is another way we can see the effect a black hole (or a large body of matter) has on its surroundings. So while we are not capturing photons in our camera of a black hole, we are getting images that have missing parts, and parts that are distorted in a way that we would expect if a black hole was present. Just because you can't directly see an object, doesn't mean you can't see the effects it has on its surroundings.
Regarding the effects a black hole has on its surroundings, you can also see when a black hole is pulling a large object into it. Let’s say a star is getting sucked into a black hole. It looks very much like water going down a drain in a bathtub. You can see the water swirl around the drain and eventually go into the drain. Imagine if you saw this happening and saw the water swirling around and then disappearing. This is what happens with the black hole. Pieces of the star get pulled off and begin swirling around the black hole. Eventually the pieces disappear as we can’t see the black hole. But again, just because we can’t see it directly, we can see black holes and take pictures of black holes indirectly.
-Brian
If the universe is always expanding, will there be superplanets of collected mass that suck us all back in again, forming a big squish? (Oscar, gr. 6, Yarmouth)
You are right to assume that the universe is expanding. In fact, Edwin Hubble (that the telescope is named after) discovered in 1929 that the universe speeds away from us faster the further away it is. Now we know that the universe is accelerating in its expansion. That means it is expanding faster and faster as time goes on.
As far as the “big squish” you ask about, it has been considered by many scientists and called several things such as “the big crunch”. In the past, scientists speculated that the universe may collapse because of the distribution of mass, the evidence points to the opposite effect. Their speculation was based on the thought that gravity would pull everything together. All observational evidence indicates the universe is expanding at a continuously increasing rate as mentioned before. This expansion is due to what scientists call dark energy. No one knows what dark energy is, we only see the effect it has. Its effect is observed to be much stronger than gravity, indicating that the universe will not collapse into a single point, but expand forever with everything getting farther and farther away from everything else. It will be very lonely.
A gif of the big crunch:
https://upload.wikimedia.org/wikipedia/commons/f/f4/Big_Crunch.gif
-GWU SPS group
