Showing posts with label Stars. Show all posts
Showing posts with label Stars. Show all posts

Saturday, October 12, 2013

Star System


Remember we learned that a planetary system is a star
with a bunch of planets spinning around it, like our solar system.

There are also stars out there that have other stars spinning around them!

We call those star systems

star system
(from: wikipedia - star system)

So far scientists have only discovered star systems with up to 7 stars in them.


Kid Facts - Blast from the past: Solar System

Saturday, October 5, 2013

Galaxy


A galaxy is a whole bunch of stars and planets all together in one area in space.

galaxy
(from: wikipedia - galaxy)

Our solar system is in a galaxy called the Milky Way
Kid Facts - Blast from the past: Planet Names

Saturday, September 28, 2013

Planetary system


We learned before that our solar system is our group of planets (like Earth and Mars)
spinning around our star which is called the Sun.

We use the word solar just for our Sun, not for other stars.

For other stars with planets that spin (or revolve) around them,
we use the name planetary system.

planetary system
(from: wikipedia - planetary system)


Kid Facts - Blast from the past: Saturn's Rings

Saturday, September 21, 2013

Interstellar cloud


An interstellar cloud is a big bunch of gas, plasma and dust floating together in space.

interstellar cloud
(from: wikipedia - interstellar cloud)


Saturday, September 14, 2013

Black Dwarf


We've now learned that our Sun is a Yellow Dwarf,
after it burns for 10 billion years it will turn into a Red Giant,
and after it burns for another 1 billion years it will turn into a White Dwarf.

That white dwarf will burn slowly for a very very long time,
over 10 Undecillion years (One undecillion is a 1 with 36 zeroes after it!),
then it will cool down and turn into a Black Dwarf.

That's such a long time, that no actual black dwarfs exist!
Scientists are just pretty sure that's what is going to happen some day.

outer space
(from: wikipedia - outer space)


Saturday, September 7, 2013

White Dwarf


We've now learned that our Sun is a Yellow Dwarf,
and that after it burns for 10 billion years it will turn into a Red Giant.

After that Red Giant burns for 1 billion years, it will turn into a white dwarf

A White Dwarf is much smaller than a Red Giant or Yellow Dwarf, but very thick.

The big star Sirius A has a very small neighbor Sirius B that is a white dwarf.

It's measurements are:
stellar classification: A1 (white)
luminosity class: V (main sequence, or dwarf)

So we can call it an A1V star, or a white dwarf.

If you look in the picture of Sirius A, you can see a very small white dot
that is the small white dwarf Sirius B.
sirius
(from: wikipedia - white dwarf)


Saturday, August 31, 2013

Red Giant


We learned last time that our sun is a Yellow Dwarf
and that it will burn for 10 billion years!

But what happens after that 10 billion years?
Well that's a long long way in the future, but once a Yellow Dwarf star burns up
it grows larger and becomes a Red Giant.

The closest Red Giant star to us is Gamma Crucis, it is 88 light years away.
Let's look at it's star measurements:
stellar classification: M3.5 (red)
luminosity class: III (giant)

So we can call it M3.5 III, or a red giant.
red giant mira
(from: wikipedia - red giant)

Red giants can be 4,000 degrees and 100 times larger than our Sun!
They usually last about 1 billion years.

Saturday, August 24, 2013

Yellow Dwarf


We've learned so much about how to measure stars now!

We now know that:
- stellar classification is how hot the star gets, and uses letters and colors, like M and red
- absolute magnitude is how bright a star is, and uses numbers from -15 to 20.
- luminosity class is heat and brightness together, and uses numbers and names like I and supergiants.
- Hertzsprung-Russel diagram is like a map for understanding all of those measurements.

Now that we understand all of that, we can understand more about the stars in our universe!

The sun in our solar system has a stellar classification of G (yellow)
and a luminosity class of V (main sequence or dwarf)

So some people call our sun a Yellow Dwarf,
and others call it a GV, but they mean the same thing!

yellow dwarf
(from: wikipedia - yellow dwarf)

Yellow Dwarf stars are about 9,000 degrees, and burn for 10 billion years!

Saturday, August 17, 2013

Hertzsprung–Russell diagram


Hertzsprung–Russell diagram might be a difficult thing to say or remember,
but it's really just a very useful thing to help you remember
the things we've been learning about stars.

Since the name is so long, some people just call it a H–R diagram or even just HRD.

We learned about stellar classification, absolute magnitude and luminosity class

The HRD is a picture map you can use
to help understand how all of those things fit together.

hertzsprung-russell diagram
(from: wikipedia - hertzsprung-russell diagram)

It was invented about a hundred years ago by two scientists,
named Ejnar Hertzsprung and Henry Norris Russell.

Saturday, August 10, 2013

Luminosity Class


We just learned that when scientists want to measure how hot a star is,
they use something called stellar classification.

When they want to measure how bright a star is,
they use something called absolute magnitude.

Looking at both a star's temperature (heat) and it's luminosity (brightness),
scientists also come up with something called luminosity class or spectral classification.

Luminosity classes are named with both a number (roman numerals like you might see on a fancy clock)
and also a name, like a supergiant or subdwarf.

The luminosity classes from biggest to smallest are:
0 - hypergiants
I - supergiants
II - bright giants
III - normal giants
IV - subgiants
V - main-sequence stars (dwarfs)
VI - subdwarfs
VII - white dwarfs

luminosity class
(from: wikimedia - hertzsprung-russel diagram)

Saturday, August 3, 2013

Star absolute magnitude


We just learned that when scientists want to measure how hot a star is,
they use something called stellar classification.

Another thing they measure for stars is how bright they are.
They call this absolute magnitude.

We can't just measure how bright stars look to us in our sky,
because some are close (like our sun) and some are very very far away.

So we measure how bright a star would be if we were looking at it from 32.6 light years away.

They go from -15 which is very very bright, to 20 which is not very bright at all.
Our sun has an absolute magnitude of 5, so it's about in the middle of the brightness levels.

(from: wikipedia - stellar classification)

Saturday, July 27, 2013

Stellar Classification


Remember that stars in the sky like our Sun
are just giant balls of burning gas floating in outer space.

When scientists want to measure how hot a star is,
they use something called stellar classification.

The letters for stellar classification from hottest to coldest are:
O, B, A, F, G, K, M.

That can be tough to remember, so you can think of it with this sentence:
Oh Be A Fine Girl Kiss Me since those first letters all match up.

A stars heat usually makes it burn a type of color,
so each of the letters has a color that goes with it.

O - blue
B - blue white
A - white
F - yellow white
G - yellow
K - orange,
M - red

Scientists like to use the letters for how hot the star is,
but sometimes it's more fun to talk about a star by it's color!

stellar classification
(from: wikipedia - stellar classification)

Saturday, July 20, 2013

Canopus


We've learned about the stars Alpha Centauri, Sirius and Betelguese.

The second brightest star in the sky is called Canopus

It can be seen in the Southern part of the night sky.
canopus
(from: wikipedia - canopus)


Saturday, July 13, 2013

Betelgeuse


We've learned about the stars Alpha Centauri and Sirius.

Another star that has a funny name is Betelgeuse, pronounced like beetle-juice.
It is the ninth brightest star in the night sky,
and part of the constellation of Orion.
betelgeuse
(from: wikipedia - betelgeuse)

Saturday, July 6, 2013

Canis Major


We've already learned that the brightest star in the sky is Sirius

Sirius is a star in the constellation Canis Major which means something like bigger dog.
canis major
(from: wikipedia - canis major)

Sometimes Sirius is called the dog star, and the Canis Major constellation
is supposed to represent one of the dogs following around Orion the hunter.

Saturday, June 29, 2013

Sirius


The brightest star in the night sky is called Sirius.

sirius
(from: wikipedia - sirius)

It can be found near the constellation of Orion.

Saturday, June 15, 2013

Alpha Centauri


We already learned about how Proxima Centauri is the nearest star to our solar system.

The next closest star is Alpha Centauri.
The neat thing about that star is that it's actually two stars!
Alpha Centauri A, and Alpha Centauri B.

They're so close that they actually look like one star.
alpha centauri
(from: wikipedia - alpha centauri)

Saturday, June 8, 2013

Proxima Centauri


The nearest star to our solar system is Proxima Centauri.
It is 4.24 light years away from us.

proxima centauri
(from: wikipedia - proxima centauri)

Remember that a light year is how long it takes to get somewhere,
traveling at the speed of light!

Saturday, June 1, 2013

Constellations - Gemini


We've now learned about the constellations the Big Dipper, Orion and Taurus.

Next up is Gemini.

This one is supposed to be two people that are twins standing next to each other.
The best way to find Gemini is to first find Orion and look to the right of Orion's belt and up a little.
gemini
(from: wikipedia - gemini constellation)


Saturday, May 25, 2013

Constellations - Taurus


We've now learned about the constellations the Big Dipper and Orion.

Next up is Taurus.
This one is supposed to be a giant bull in the sky.
The best way to find it is to first find Orion, then look to the left of Orion's belt and you should see a bunch of stars that make up a V shape.
That's Taurus!

Follow the points of the V and you should find two stars that make up the points of the bull's horns.

taurus
(from: wikipedia - taurus constellation)