So, I'm Neil deGrasse Tyson, your personal astrophysicist

and I was invited in with these fun props

like inflated planets to answer questions,

your questions about the universe.

So, bring it on.

(lively instrumental music)

Questions from the internet.

I got one here from Kane Jackson.

How many stars are born per year?

How many die?

Well, it's about 100 a year in our galaxy.

We've had like a stable amount

for the last several billion years.

And the way you calculate that is we have

about a hundred billion stars in the galaxy

and the universe is 10 or so billion years old.

It's about 100 a year, between 10 and 100 a year,

so you got it.

Next up, from Macabees.

Dude, I love questions that begin with dude.

There's literally a quark called strangeness

coz nobody frickin' knows what the hell it's doing

or what is going on.

Damn I hate physics.

That's not a question.

(laughing)

We have quarks named up, down, bottom, top,

strange and charmed.

We don't see them directly.

We can't tell you what we, we can't show you a photo

of them, so they're just placeholder words for them.

So, just like, just get used to that.

All of quantum physics transcends our

personal life experience, so to describe it,

we have to sort of invent words.

One of them is just strange.

That doesn't mean we can't describe it

and know what it, how it behaves in and of itself

and with other quarks.

So, don't put too much meaning into word itself.

It's the idea that matters.

Next, Jordan.

Is is just a coincidence that two major hurricanes,

a spreading wildfire and now an 8.4 magnitude earthquake

followed the solar eclipse?

Yes.

By the way, there's solar eclipses every 18 months or so.

Find something that happened there,

and you want to blame it on the eclipse?

Okay, go ahead.

People did that for millennia.

No, no.

What do we have here?

A DaggerAPM, If dark energy makes the universe expand,

it might make more or new space.

Can we use that space to make dark energy out of it?

I don't know.

By the way, dark energy is not so much making us expand.

We were already expanding.

It is making the expanding universe accelerate.

That's what's going on.

Evidence shows that dark energy is not being created

in the expansion of the universe.

So, I think the answer to this is no.

But, if one day we could control dark energy in a lab,

maybe we might discover interesting properties

in its relationship to dark matter.

I don't know.

(keyboard clicking)

To be determined.

Watch this space.

Next up on Twitter.

Charles William Johnson.

If the Higgs-Boson, et cetera,

forms an essential part of reality, which it does,

why can't it be found in our front room

or all around us?

There's certain parts of our fundamental reality

that you only gain access to under certain conditions

of pressure and temperature and energy.

You don't experience a proton in your life,

but it's a fundamental part of nuclei

that make up the atoms that comprise your body.

So, just 'cause you don't see it, feel it,

touch it, taste it or smell it does not mean

it does not exist.

And part of the entire purpose

of why we have science at all,

in particular the methods and tools of science,

is to decode that which is true about nature

that otherwise transcends your sensory perceptions.

That is what science is.

You wouldn't need the tools if our brain sensory system

accurately decoded the world around us, but it doesn't.

And that's why science tries to find any way it can

to remove your brain, eye, ear, nose, mouth, touch

from the operation.

And the more we can successfully do it,

the less bias shows up in the result.

Just get the human out of it.

So, yeah, reality is not what you perceive.

It's what the methods and tools of science reveal.

Next up, Wow, Across the Universe is a musical?

I don't know.

Is it?

I love musicals.

If it is, I'm embarrassed that I haven't heard of it,

but it ought to be.

Seems to me the universe would be really good.

Next, Marilyn Baker.

What is a quantum particle?

Is it like say a quark?

Or is it an electron or what?

Quantum physics is the study of everything

that matters on that scale.

Electrons, quarks, neutrons,

nuclei themselves, atoms themselves,

molecules themselves.

There is no understanding of what they do

without quantum physics.

That's how small particles roll in this world.

Hope that answers your question.

Within these hundreds of newly confirmed ExoPlanets,

how many are possibly habitable

by the actual scientific method we have?

So, you look for exoplanets, planets orbiting other stars.

Some fraction of them are in the Goldilocks Zone,

not too close.

If it had liquid, water would evaporate.

Not too far.

If it had liquid water would freeze.

I mean, calculate with that is for any star.

And so, there's subset of all the thousands of exoplanets.

There's a few hundred that orbit in the Goldilocks Zone.

Life as we know it could thrive there.

Haven't found life.

Still lookin' for life, but it could thrive there.

By the way, there are other sources of heat,

sources of heat from tides that are created

from the main planet, Jupiter, for example,

onto its moons.

So, there are moons of Jupiter.

Jupiter's way outside the Goldilocks Zone.

The moons of Jupiter are kept warm

by this sort of gravitational massaging

that's called tidal heating, T-I-D-A-L, tidal heating.

So, you might have life as we know it on the moons

of planets that have tidally heated those moons.

So, that opens the net if we cast a much wider net

in the search for life in the universe.

Not sure if anyone has asked or answered, but I'm curious.

Where was Neil Tyson for the solar eclipse?

Hopefully it was a clear sky.

Thank you for those warm wishes.

It was a state secret where I was

right up until the eclipse.

I was at Deadwood Lookout,

7,200 feet up in the mountains of Idaho.

Oh, yeah.

Checkin' out the total solar eclipse.

Yeah.

Is the universe expanding into a space bigger

than the universe itself?

Is there a clear limit to the expansion?

So, yeah, we're expanding, but if that's what

we define all of space to be,

than there's higher dimensions into which

this is happening.

In principle, you can go outside of our universe

and look down on it or up to it,

but then you're in another dimension.

So, we don't have access to that dimension,

so we're stuck with the dimension that you're given,

three spatial one-time dimension.

Get over it.

Time for just a couple more.

What do I have here?

A Dani Yell, If aliens exist,

how do I know I'm not one?

Well, if you visited another planet with life,

you'd be an alien to them clearly.

You're probably not an alien because you share

all the same organs in the same place

with the same biochemistry and highly common DNA

with the person sitting across from you

and everyone else walking this earth.

You have DNA in common with yeast cells,

with an apple, with oak trees.

So, that's some of the best evidence we know

that you yourself are not an alien.

Jacob Warren, Y'all believe in quantum mechanics

or theory of relativity?

Which one is better?

(laughing)

You don't have that choice.

They each exist and work and make predictions

that are verified.

They're both kind of crazy, but they apply to reality.

Now, it turns out, we already know the limits

of relativity.

It can't describe the center of a black hole.

So, we know relativity will have to be extended

or modified in those extremes to understand that.

Quantum physics, quantum mechanics,

it works every single place we have ever applied it.

Every single place.

So, in that regard, it is the most successful theory

of the universe that has ever been put forth.

It could be possible that in the future,

quantum physics will subsume relativity entirely

to get you to those singularities,

the center of the black hole

and the beginning of the universe.

But, right now, they both work

and we're completely happy with them.

Last one, Nefilian, Twitter.

So, the theory of relativity, the prediction

of the effects of gravitational fields in space then?

Peace.

(laughing)

I think the rise of science has promoted greater peace

and prosperity in the world.

Certainly prosperity.

And often where there's prosperity,

there's less of a need to take your neighbor's stuff.

If you look at the era of science,

and look at the kinds of wars people fought,

and what fraction of people would die in a war

of a culture.

In spite of even these aberrations

such as the First and Second World War,

a much smaller fraction of all humans died

in those wars than who died in tribal wars

if you go back thousands of years.

You could lose a 1/3 of your men fighting in a battle

just to gain access to property.

That does not happen in organized war.

No war is good, of course,

but it may be that science as a path to prosperity

and health, will remove many of the reasons

why we ever had war in the first place.

So, a theory of relativity as another branch of physics,

science in general, peace, yeah, peace.

Yes.

So, very impressed with the cosmic curiosesity out there.

Keep 'em comin' and as always, keep looking up.

You guys know about this?

It's basically a thermometer.

It's a closed system and there's air in here.

Room temperature is generally cooler

than your body temperature.

This is why we have to eat continuously

as warm-blooded creatures to maintain

this temperature difference.

We're basically 100-degree organisms, right?

Air is 70 degrees, so if I warm this air, then

(lively instrumental music)

there it goes.

Is that cool?