Warp Drive

I'm going to detour a little bit from talking about the Sun to talk about something new that has come up this week: NASA Physicist unveils warp-drive craft design

Now, if you read the article, make sure you note that this is what it would look like, much like what the NX-01 Enterprise looked like from Star Trek: Enterprise TV Series.

We are not capable of creating an engine that can allow so-called faster-than-light travel.

 

I call this so-called because technically, warp drive does not allow faster-than-light travel, but apparent faster-than-light travel.  What warp drive does is warps the space ahead and back of the ship, compressing space in front and expanding space in back.  This would allow the ship apparently to move faster than light.

Special relativity tells us that faster-than-light travel is impossible in normal space, but warp drive gets around this by creating a bubble around the ship, again warping space around the bubble.

Faster-than-light travel is impossible in normal space because relativity states that the closer to the speed of light an object gets, the heavier it gets.  At the speed of light, any object with mass has an infinite mass. Therefore, to accelerate something to the speed of light requires infinite energy.

Conceptually, this is what warp drive would look like.

As you can see in front of the Enterprise, space is compressed and behind the Enterprise, it is expanded.  Unfortunately, the physics to allow warping of space is unknown and probably won't be known for a few decades or centuries.

If you are reading this...

Let me know in the comments how you found me and why you are reading this blog.

Thanks!

The Gassy Star

The Sun is gaseous...in more ways than one.

We already know that the Sun is giant ball of plasma that gives off a lot of light and heat, but did you know the Sun also belches hot gas from its surface?

These belches are called solar flares and the gas and plasma given off are called solar prominences.

 

As you can see from the image, the prominence actually is curved.  The prominence is magnetic and follows along magnetic field lines eminating from sunspots (which will be covered later).  The prominence is most obvious when looking at the limb (edge) of the Sun, but can also be seen on the face of the Sun.

When the prominence is seen on the face, that is called a filament.

Looking closely, you can also see prominences along the limb of the Sun.

 

If a flare is really energetic, it can give off coronal mass ejections which can really wreak havoc on Earth. CMEs can disrupt satellite communications and any spacecraft in orbit around the Earth.

 

 

SOHO (the Solar Heliospheric Observatory) took these images to show how energetic CMEs can be. The image on the left shows that the CME is as big as the Sun itself.

 

All of these are examples of an active Sun.  Another examples is the solar wind which gives rise to beautiful auroras near the poles of the Earth. If the Earth did not have its magentic field, however, the solar wind would cause the Earth to have a really bad day.



The Layers of the Sun

Last time, we learned that the Sun does not rotate uniformly.  Today, we will learn that the Sun is made up of many layers, much like the Earth has different layers.  However, the Sun's layers are different.

Image from Australia Telescope National Facility

 

 

As we can see from the image, there are three layers in the interior of the Sun.  The Sun also has three layers above the surface.

 

From the interior out, the six layers are:

1. The core where all the fusion and energy production occurs
2. The radiative layer (which is the subject for a later post)
3. The convective layer
4. The photosphere - the "surface" of the Sun. This is what we see when we look at the Sun, which you shouldn't
5. The chromosphere
6. The corona

What is unusual about the Sun is everything in the five outer layers have not changed since the Sun was formed.  There are distinct boundaries that keep the layers from mixing.

 

All the hydrogen that has fused in the Sun was in the core at the Sun's birth.  None of the outer layers will change over the course of the Sun's life.  Eventually, the material that makes up the Sun will end up in another star and probably be converted into other material.

 

 

Solar Non-Uniform Rotation

Remember in the last post, the Sun is described as a "miasma of incandescent plasma"? In order words, it isn't solid.

We have this large ball of plasma that rotates. But because it isn't solid, different latitudes orbit at different rates.

Imagine we have a long rope that can withstand the immense heat of the Sun. We tie either end to the rotational axis on either pole and attach the rope to the Sun's surface.. We have something like this.

 

We allow the Sun to rotate, and we begin to notice something.  The rope nearest the equator is moving faster than the rope nearer the poles.  Now the rope looks like this.

 

How do we know this happens? We are able to observe the sunspots on the Sun and can see those spots near the equator are farther ahead compared to the spots in higher latitudes.  By measuring the speed of the spots, scientists were able to determine that the Sun takes about 30 days to rotate near the poles and only about 25 days at the equator.

We also notice the same differential rotation on the gas giants as well.

The Sun is a mass of incandescent gas...

Many people probably have heard the song by They Might Be Giants called "Why Does the Sun Shine"

Oh wait, this is incorrect.  The Sun is not a mass of incandescent gas. It's actually what scientists call a plasma*.

 

*a plasma is a state of matter that is similar to gas except that all the molecules are ionized.

 

They Might Be Giants kindly updated the song to be scientifically correct.

 

So why is the Sun wacky?  It's been shining since day one of Earth some four and half billion years ago, so we know everything about it, right?  Well, maybe, but there are some strange things about it.

 

 

1) The Sun does not rotate uniformly

2) The Sun is highly differentiated

3) The Sun belches...a lot

4) The Sun has belimishes

5) The light we see on Earth actually is hundred's of thousands of years old

6) The Sun is actually very average compared to other stars. Wait, that's not strange. Or is it?

 

 

The next few blog posts will explain these six things, so stay tuned for more.....

 



Beginnings....

I've started a new blog that I hope to share the strange and weird universe we live in.  I hope to convey my love of how the universe is beautiful yet wacky at the same time.

Before we begin, I'd like to give a few definitions of some terms that I will be using on this blog.

sidereal period: the period of time (rotational period, orbital period) where a spot on an object takes to either rotate to get the same star in the sky or where an alignment between two objects is identical to a background star.

synodic period: the period of time for an object when the Sun is at the same location in the sky.

Here is a link explaning it a little better.

Astronomical Unit: the average distance from the Earth to the Sun. It is 93 million miles or 150 million kilometers.  Astronomers generally use metric to describe quantities whether it is distance or mass.

Year: the length of time that a planet takes to orbit the Sun once.  In this blog, I'll be using the term Earth year when describing years for other planets.

Day: the length of time it takes a planet or satellite to rotate once.  The sidereal day and the synodic day, however, are not the same.  See above.

Moon and satellites: natural bodies orbiting around planets or minor planets.  They generally are used interchangeably.

If other terms come up, I will try to explain them as they arise.