Tag Archives: Charon

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3/4B, 4T and 3SF visited the Penrith University of Western Sydney Observatory and share their experience in a blog post. They also asked questions and I loved the challenge of trying to answer them. To see their post…

Bloggers of the Week: Our Excursion to the Observatory

To see Part 1 of this comment...

Observing Space, there’s so much of it out there – Part 1

Hello 3/4B, 4T and 3SF,

Here are some possible answers to the second set of questions.

1. How many more years until we have to pack up and move to another planet, because the sun died?

Schools and students have permission to use this graphic for non-commercial, educational purposes.

Schools and students have permission to use this graphic for non-commercial, educational purposes.

Firstly, let's look at how our Earth is thought to have come to be. Heather and Keira from California had challenged me to explain how the Earth had begun. Here is a link to the post I wrote for them if you are interested.

How Did the Earth Begin?

... and here is a link to a Wikipedia post looking at history of the Earth. It is about  Earth from its formation to now.

History of the Earth

Okay, we have an idea how our Earth began but how might it end? As our planet's birth was linked to the formation of our sun, the sun is also involved in its suspected end.

Back in 1987, I was able to look into the night sky and see a "new" star. A star astronomers named SN 1987A had gone supernova. It is about 168,000 light years* from Earth and could not normally be seen without a powerful telescope. It is again too dim to be seen without a telescope. Had it been our star, our planet would have been destroyed.

Then what about our Sun? How old is it? What might happen to it? When might it happen?

This is a NASA photo released into the public domain. It was sourced through Wikimedia Commons. http://commons.wikimedia.org/wiki/File:The_Sun_by_the_Atmospheric_Imaging_Assembly_of_NASA%27s_Solar_Dynamics_Observatory_-_20100819-02.jpg

This is a NASA photo released into the public domain. It was sourced through Wikimedia Commons.
http://commons.wikimedia.org/wiki/File:The_Sun_by_the_Atmospheric_Imaging_Assembly_of_NASA%27s_Solar_Dynamics_Observatory_-_20100819-02.jpg

Our Sun is thought to be about 4.6 billion (4,600,000,000) years old. I had to do a little research about the Sun to find out what might happen. I found interesting information suggesting our Sun is becoming brighter by about 10% every billion years and it's surface is slowly becoming hotter. As it gets older and burns more of its hydrogen fuel it will grow in size to eventually become a red giant. By this time Earth, if it still exists, will not be able to support life.

The video clip below shows what might well happen when our to end of world. Duration: 3:04 minutes.

It replaces the original linked video clip now blocked from viewing in Australia due to copyright issues.

This is not my video clip.

Should we worry?

It is thought it could take about 5 billion (5,000,000,000) years before our Sun is a red giant and perhaps 1 billion (1,000,000,000) years before the Sun's rising temperature means all water will evaporate away from Earth. A billion years is a very long time. However humans develop in that time, we can only hope they have solved the problems. For a time until the sun gets too big or hot this might mean people moving to Mars but to go to other stars people might have to spend a very long time in space. By the time people reach other stars, they could be the great, great, great, great,... great, great, great, grandchildren of those who left Earth.

But I've seen movies where they move through gates or hyperspace at faster than the speed of light and arrive quickly...

The movies love finding ways to arrive quickly. Who knows what science might discover in a billion years. For now, the idea of travelling close to the speed of light is beyond us. Whatever the future brings, I have faith humans will find a solution if there's one to be found. I know NASA engineers are looking at ways it might be one day possible to warp space and make travel to the stars real. 🙂

168,000 light years* - as explained in Part 1, a light year is the distance light travels in a vacuum in one Earth year. While I saw the supernova as a bright star in 1987, the light had started on its way 168,000 years ago. When we look at stars, we are looking back in history. Even light from our own sun started its journey about 8.3 minutes before we see it.

2. Did you know that there are many different galaxies in space?

Yes. Too quick an answer? 🙂 I'll share some NASA galaxy photos using links.

The two galaxies shown here are in the early stage of an interaction that will eventually lead to them merging in millions of years. The two galaxies are about 450 million (450,000,000) light years from us. If you look carefully you can see other galaxies in the distant background.

UGC 9618, Chandra + Hubble

By Smithsonian Institution [Public domain], via Wikimedia Commons

This second photo shows galaxy M33. It is about 3 million (3,000,000) light years from Earth. The really bright stars are young, very large stars. Yes, stars are still being made in our universe from the remains of other stars.

Galaxy M33 Chandra X-ray Observatory

By Smithsonian Institution from United States [see page for license], via Wikimedia Commons

The third photo shows galaxy Centaurus A. If you can see what looks like a line of white light coming from its centre, that's the result of Centaurus A having a supermassive black hole at its centre.

Centaurus A Chandra

By NASA/CXC/CfA/R.Kraft et al (http://chandra.harvard.edu/photo/2008/cena/) [Public domain], via Wikimedia Commons

Galaxies are not all one size. Dwarf galaxies might only have as few as 10 million (10,000,000) stars whereas giant galaxies might have up to 100 trillion (100,000,000,000,000) stars. There are estimates the might be up to 170 billion (170,000,000,000) galaxies in the observable universe . There may be very many more but they are so distant their light still hasn't reached us, they're not yet observable. That's a lot of galaxies.

I like looking at big numbers so let's look at big numbers. I have said their might be 170 billion (170,000,000,000) galaxies in the observable universe. I also said galaxies could have from 10 million to 100 trillion stars. Let's say the average galaxy has 1 billion (1,000,000,000) stars.

How many stars might their be in the observable universe?

170,000,000,000 galaxies x 1,000,000,000 average stars = 170,000,000,000,000,000,000 (I make that 170 quintillion stars.)

In Part 1 of these answers to your questions I mentioned it has been said there are more stars in the universe than all of the grains of sand on every beach on Earth. Would one of you start counting so we can check? 🙂

Below is a You Tube video clip from NS showing galaxy M31 known as the Andromeda Galaxy. It is the nearest large spiral galaxy to our own. Our galaxy, The Milky Way, is also a spiral galaxy. Duration: 3:06 minutes

This is not my video.

3. Did you know that Pluto has 2 more moons?

Yes, but I found there seems to be more discoveries when I was researching. In order of distance from Pluto they are Charon, Styx, Nix, Kerberos, and Hydra. It is possible more small "moons" might be found. Click to read Moons of Pluto on Wikipedia.

In this photo taken by NASA in 2005, the two dots listed as candidate satellites
Pluto system 2005 discovery images

When Pluto was discovered in 1930, its brightness suggested it was much larger than it was found to be but that was because it is icy. Charon was discovered in 1978. I always found its name was a great choice. In ancient Greek mythology, Pluto was the god of the underworld where people went when they died. To reach there, you had to cross the River Styx. This could only happen if you had a coin to pay the boatman, Charon. It was common for ancient Greeks to bury their dead with a coin so they could pay Charon. This is why I thought the name is a good choice. Pluto and Charon are together in ancient Greek mythology.

One unusual piece of information I read was about Pluto and Charon. Moons orbit around their planet as does our moon but Pluto doesn't seem to be the centre of Charon's orbit. The centre of orbit is somewhere in between but closer to Pluto. What a strange place Pluto would be.

While searching online, I found an animated file showing a computer generated rotating image of Pluto you might like to see. It's based on NASA images of the surface of Pluto. This an embedded NASA file in the public domain.

Pluto animiert 200px
By Aineias, NASA, ESA, and M. Buie (Southwest Research Institute)  derivative work: Aineias, Ilmari Karonen (Pluto_hubble_photomap.jpg via Pluto_animiert.gif) [Public domain], via Wikimedia Commons

4. Did you know that Neptune's ring is made out of ice particles?

Below is my favourite image of Neptune. NASA released this image into the public domain. Neptune's atmosphere seems to be mostly hydrogen and helium. "The interior of Neptune, like that of Uranus, is primarily composed of ices and rock." (Wikipedia). Remember, ices aren't necessarily only water. Have you heard of dry ice we can buy here on Earth? It isn't water. It's icy carbon dioxide. For Neptune, the ices are thought to be mostly water, ammonia and methane. The core of the planet is said to be rocky.

Neptune

By . (http://photojournal.jpl.nasa.gov/catalog/PIA00046) [Public domain], via Wikimedia Commons

The next NASA image was taken by the Voyager 2 and shows the rings on Neptune.

Neptune rings PIA02224

By Courtesy NASA/JPL-Caltech (http://photojournal.jpl.nasa.gov/catalog/PIA02224) [Public domain], via Wikimedia Commons

The rings are thought to probably contain large amounts of micro-dust as well as ice.

 

5. Did you know that it takes 1 month for the moon to orbit around the earth?

Wikipedia reference for the different types of months and years: Month

This embedded graphic shows the phases of the Moon seen as it orbits the Earth. Do you notice we only see one side? The other side is often called the dark side. It also comes into sunlight but, since it faces away from Earth, we don't see it.

File:Lunar libration with phase Oct 2007 450px.gif

This work has been released into the public domain by its author, Tomruen. This applies worldwide.

This is an interesting question even if it sounds simple. Rather than say "yes" or "no", I might ask what type of month?

I know the months we talk about run from January to December. February has 28 days or 29 in a leap year. The others have either 30 or 31 days. The average number of days in a month is about 30.4 days. If you mean one of our Gregorian Calendar months we use, the answer is not quite a month.

When compared to the position of stars, the Moon takes about 27.3 days to orbit the Earth but Earth is also moving through space so the time between two full moon is about 29.5 days.

Did you know there was something known as a lunar calendar?

The calendar we use is a solar calendar. It's based on the time it takes for the Earth to complete one orbit around the Sun. Lunar calendars are different because they are based on cycles of the Moon.

Many cultures have had lunar calendars.  One of the important examples is the Islamic Calendar. A year has either 354 or 355 days where as the Gregorian Calendar has 365 or 366 days based on a solar year. If you have Muslim friends, you might know the first day of their new year is a different day on our calendar each year. This happens because their lunar year is 11 days shorter.

The Gregorian solar year has an average of about 30.4 days per month giving us about 365 days a solar year.

The Islamic lunar year has an average of about 29.5 days per month giving us about 354 days a lunar year.

Can you see the solar calendar gives us about the time it takes for the Earth to complete an orbit of the Sun while the approximate number of days in a lunar month is how long it takes the Moon to go from one full moon to the next?

The embedded diagram below shows how the phases of the Moon come about while the Moon orbits Earth.

Moon phases en

By Orion 8 (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons

6. Did you know that (it takes) a year for the earth to orbit around the sun?

Our Gregorian solar calendar is based on how long it takes the Earth to complete one orbit of the Sun, that is it takes about 365.25 days for Earth to orbit the Sun. We call that a year of 365 days with a leap year helping us catch up on the extra bits by having an extra day.

UpdatedPlanets2006

By Adam850 at en.wikipedia [Public domain], from Wikimedia Commons

What would a year be on other planets and dwarf planets?

Here are the other planets and known dwarf planets in our Solar System with how long their years would be in our Earth years (Ey).

Mercury ....................... 0.24 Ey (88 days)

Venus ........................... 0.62 Ey (226 days)

Earth ............................ 1.0

Mars ............................. 1.88 Ey

Ceres (dwarf) ............... 4.6 Ey

Jupiter .......................... 11.86 Ey

Saturn ........................... 29.46 Ey

Uranus .......................... 84.01 Ey

Neptune ....................... 164.8 Ey

Pluto (dwarf) ................ 248.09 Ey

Haumea (dwarf) .......... 282.76 Ey

Makemake (dwarf) ...... 309.88 Ey

Eris (dwarf) ................... about 557 Ey

A little extra...

In July last year a class asked some questions about space. I didn't add and pictures to the post but you might like to see their questions and my answers...

Wonderings About Space

* * * * * * * * * *

And one final You Tube video clip answers,

"What Is Space?"

Duration: 55:43 minutes

This is not my video clip.

3/4B, 4T and 3SF visited the Penrith University of Western Sydney Observatory and share their experience in a blog post. They also asked questions and I loved the challenge of trying to answer them. To see their post...

Bloggers of the Week: Our Excursion to the Observatory

To see Part 2 of this extended comment post...

Observing Space Part 2

Schools and students have permission to use this graphic for non-commercial, educational purposes. This is not a real star photo but one I created.

Schools and students have permission to use this graphic for non-commercial, educational purposes. This is not a real star photo but one I created.

When we look out at night, staring into space, we come to realise space is big, very BIG. I have heard it said if we were to count all of the grains of sand on all of the world's beaches there would still be more than that number of stars in our universe. This helps us realise there is so much more to know than we can possibly see.

At the end of last year, I prepared a short video clip about a small community known as Earth. It was for a class looking at ways of making a difference globally. It shows we can start by looking at ourselves and as we expand our view we move out into the universe.

Schools and students have permission to use this video clip for non-commercial, educational purposes.

As there is quite a lot to cover, this comment has been broken into 2 parts, each dealing with 6 questions on the class blog.

Hello 3/4B, 4T and 3SF,

I was fascinated by your post entitled “Bloggers of the week: Our excursion to the Observatory”.  I have very many interests in many subjects but the sciences are particular favourites. While I was a primary school teacher before retiring, I held a degree in science. Seeing your questions, I knew I had to try to give answers to as many as possible.

Let’s start with one you have answered…

1. How do solar eclipses happen?

“Solar eclipses happen when the Moon crosses over the sun and shines a shadow over a part of the earth.” I have prepared a diagram you can use if you wish...

Schools and students have permission to use this graphic for non-commercial, educational purposes.

Schools and students have permission to use this graphic for non-commercial, educational purposes.

If you look at the diagram, it shows the shadow of the Moon cast on the Earth. In the centre of the shadow there is a very dark area know as the umbra. The umbra is the area of total eclipse. The lighter shadow area is the penumbra or area of partial eclipse. The faint lines I have added help show why we have darker and lighter areas.

WARNING: You all know you should never look directly at the sun. The light entering your eyes can cause blindness if you stare at the sun. Only when there is a total eclipse is it safe to look but only until the sun is about to reappear. You cannot even look at the Bailey's Beads or Diamond Ring effect as this is still direct sunlight.

One of the most amazing parts of viewing a solar eclipse is when the sun starts to reappear. The Moon's surface isn't smooth. There are craters, mountains and valleys. Light first appears through gaps. Light appears in what is known as Bailey's Beads. When only one bead is left we have what is known as the Diamond Ring Effect. Here is another diagram I drew to show what the Diamond Ring Effect can look like.

 

Schools and students have permission to use this graphic for non-commercial, educational purposes. This not a photo but a created graphic.

Schools and students have permission to use this graphic for non-commercial, educational purposes. This not a photo but a created graphic.

Did you also know there are lunar eclipses?

In a lunar eclipse, the Earth passes between the Moon and our sun. You can find out more with the link.

The video clip below comes from You Tube. It shows the 2012 total solar eclipse filmed in Northern Queensland. Once the eclipse is total, the camera person swaps filters and you can see the total eclipse more clearly. Keep watching and you will see the "diamond ring". Duration: 4:35 minutes

2. Can you bungy jump on the Moon?

I loved this question. There might be some tourism potential there.

Schools and students have permission to use this graphic for non-commercial, educational purposes.

Schools and students have permission to use this graphic for non-commercial, educational purposes.

I see it’s been suggested you can’t because there is nothing to land on but I think it would be possible. You may have read gravity on the Moon is only about one sixth that of Earth. That would mean someone weighing about 36kg on Earth’s surface would weigh only about 6kg on the Moon. Of course, there is very little atmosphere on the Moon and solar radiation would be a big problem so a space suit would be necessary and that would add weight. Okay, we have gravity and weight to make us fall. What next?

Bungy jumps on Earth are usually over water from a bridge. If the cord breaks, you get wet. On the Moon, the only suspected water would be in craters where direct sunlight doesn’t hit but it would be ice so there is no liquid water. A broken cord would mean hitting the ground. You might be much lighter but it would still hurt but what a thrill to be the first.

Height is not a problem. There are craters, peaks and valleys on the Moon so in the future some enterprising tour company might be able to set up a bungee site. Look at the below photo from NASA released into the public domain…

This is a NASA photo released into the public domain. It was sourced through Wikimedia Commons. http://commons.wikimedia.org/wiki/File:Lunar_crater_Daedalus.jpg

This is a NASA photo released into the public domain. It was sourced through Wikimedia Commons.
http://commons.wikimedia.org/wiki/File:Lunar_crater_Daedalus.jpg

Now here’s a thought in a different direction. When astronauts have gone on “space walks” tethered only to their spaceship by a cord, are they bungy jumping or going space skiing?

While no one has been able to bungy jump on the Moon, back in 1971 Alan Shepard (Apollo 14 astronaut) hit two golf balls on the Moon. Duration: 1:35 minutes

This is not my video clip.

3. What is the biggest gas planet?

Wikipedia reference: Gas Giant

Schools and students have permission to use this graphic for non-commercial, educational purposes.

Schools and students have permission to use this graphic for non-commercial, educational purposes.

Again I see an answer has been given. I agree. Jupiter is the largest gas planet in the Solar System. Planets larger than around 10 times Earth's mass are said to be giants.

There are four in our Solar System: Jupiter, Saturn, Uranus and Neptune. To be a gas giant, they have to be mostly gaseous.

Jupiter and Saturn are mostly hydrogen and helium. Each of these are gas giants.

Uranus and Neptune could be called ice giants. They are thought to have a hydrogen atmosphere but icy cores of water, methane and ammonia.

Did you know stars are gas giants? Huge masses of mostly hydrogen is found in newer stars. If a gas giant is big enough, a nuclear reaction known as fusion can start and a star is born. It's estimated a gas giant about 13 times the size of Jupiter might be big enough to start fusion. Imagine if Jupiter had been big enough. Our sky would have our bright sun and a less bright star known as Jupiter.

Jupiter is the biggest gas planet but our sun is the biggest gas object in our Solar System. Astronomers tell us compared to the largest stars in our universe, our sun is really small. There's a lot of gas out there. 🙂

This You Tube video clip shares some information about the four gas giants in our Solar System. Duration: 8:19 minutes

This You Tube clip is not my work.

4a. What is the smallest planet in our Solar System?

Another answer has been given, Pluto. I will give an answer but to do this I will answer a question out of order. Above is 4a and below is 4b.

4b. Why isn't Pluto considered a planet anymore?

Wikipedia reference: Pluto

In my book library, I have some old science books. One set of five was published in 1919 and the other was a book published in 1930. In 1919, science spoke of the eight planets in our Solar System. In order from our sun, they were Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Mercury, closest to the sun, was the smallest planet.

Some astronomers noticed something unusual in the orbit of Neptune. They suspected there was another planet. The 1930 science book mentioned the possibility of a ninth planet. It was in that year the discovery of Pluto was announced. It became the ninth planet and was listed as the smallest.

This is a NASA photo released into the public domain. It was sourced through Wikimedia Commons. http://commons.wikimedia.org/wiki/File:Pluto_System.jpg

This is a NASA photo released into the public domain. It was sourced through Wikimedia Commons.
http://commons.wikimedia.org/wiki/File:Pluto_System.jpg

So why isn't it a planet now?

Pluto is now known a a dwarf planet. It is only one five hundredth Earth's mass. Think of it this way. If Earth's mass was one hundred $1 coins, just one $1 coin would be the mass of five Plutos.

We didn't really know how small Pluto was until the late 1970s. Since then Charon has been discovered as a moon of Pluto, followed by two more moons named Nix and Hydra in 2005. Other large objects almost the size of Pluto had also been found. Astronomers believed there are many large objects (watch the video clip below). They realised it was probably only a matter of time before an object larger than Pluto was found. This happened with the discovery of Eris in 2005. Astronomers decided there had to be a way of saying whether objects were planets. This was done in 2006.

From Wikipedia, here is what a mass needs to be if it is to be called a planet...

  1. is in orbit around the Sun,

  2. is nearly round in shape, and

  3. has "cleared the neighbourhood" around its orbit.

Wikipedia reference: IAU Definitiion of Planets

Pluto passed 1 and 2 but failed 3 and so is now known as a dwarf planet. Mercury is again the smallest planet in our Solar System.

Since then, other dwarf planets have been identified. They are Eris, Ceres, Haumea, and Makemake. The closest dwarf planet to Earth is Ceres. Ceres is in the asteroid belt between Mars and Jupiter. When it was identified as a dwarf planet, it became our closest.

In the video clip below, "Why Pluto is Not a Planet", it's explained why Pluto is now known as a dwarf planet. Duration: 4:54 minutes

This is not my video clip.

5. What is a light year?

Schools and students have permission to use this graphic for non-commercial, educational purposes.

Schools and students have permission to use this graphic for non-commercial, educational purposes.

A suggested answer was, "A  light year is the speed of light when light travels."

Let's look at this.

Some people make the mistake of thinking of a light year as time or speed. It isn't. A light year is a distance. It is the distance light travels through a vacuum (no air) in an Earth year. The suggested answer wasn't correct because it suggests a light year is a speed.

How far is a light year?

In just one second, light in a vacuum can travel almost 300,000km. Do you think a police officer would be able to catch speeding light?

According to Wikipedia, a light year is a distance of a little under 10 trillion kilometres.

1 light-year = 9,460,730,472,580,800 metres

1 light-year = 9,460,730,472,580.8 kilometres

If your family car was able to travel into space for one light year distance at an average speed of 100kph, it would take you around 95 trillion years. Can you imagine how much the fuel would cost and how many times you would ask your parents when you will arrive? 🙂

Our sun is about 149,600,000 km from us. Your family car would take around one and a half million years to reach it if your car travelled at 100kph but light only takes around 8.3 minutes.

With next closest star to us being about 4.37 light years distant, I think you might start to understand why travelling to planets around another star is way beyond what we can do.

BUT WAIT... I found this video clip on You Tube while looking for other information. A NASA engineer was interviewed this year about the idea of warp space. It's said we can't travel at the speed of light for reasons I won't explain here but the engineer was talking about warping (expand and contract/grow and shrink) space. If this is one day possible, travelling to the next nearest star to our Sun might be possible in weeks or months but this is a long way off if it's possible.

This is not my video clip.