- Education and Science»
- Astronomy & Space Exploration
To Boldly Go, the Mission to Pluto
To Boldly Go, and the spaceship that went!
We made it! We got there! Okay not me but NASA got there! All the way to the edge of our solar system and right to the limit of "known space" right out to the orbit of the sphere that used to be known as the ninth planet in our solar system, PLUTO.
After an epic ten year journey NASA finally got a spaceship or 'Probe' all the way out to the last outpost of our solar system to have a look around and see what it could tell us about the neighborhood. What did they find?
Meet the neighbor
First discovered in the early 1930's by astronomer Clyde Tombaugh who was looking for the hypothetical massive planet believed (at the time) to be orbiting out beyond Neptune and affecting the orbit of other planets in the solar system. He was literally looking in the right place at the right time!
Going back as far as the 1840's astronomers were using Newton's calculations to work out that there was at least one more large planet "out there" that was affecting the orbit of the six planets that were known at the time. Not long afterwards Uranus was discovered and then Neptune, but that still didn't explain some of the orbits. Using Newtonian mechanics they were able to work out where to look for the elusive "planet X"
The first person to actually get an image of PLUTO actually did it without realizing he'd got the images!
As early as 1909 observatories were getting images of PLUTO without knowing what they had. On April 7th 1915 Percival Lowell took images of her but still didn't realize what he had, they are the earliest images of PLUTO that we know of!
At first pluto was thought to be about the size of the Earth and was given the designation of being a planet but slowly over the years as astronomers pointed better telescopes at her she seemed to shrink until finally it was realized that she was only about one sixth of the size of the moon.
The first ever pictures of Pluto
A voyage to Jupiter
Where is Pluto exactly?
Everyone remembers the lessons from school and each of the planets
1. Mercury, messenger of the 'gods' is the closest to our sun. At about thirty two to six million miles it orbits the sun every 87 days and is roughly half the size of Earth
2. Venus, named after the Roman goddess of love. Second planet from the sun and its pink color gave rise to the name. The truth is Venus has a very thick atmosphere made up primarily of Sulfuric acid making it one of the most inhospitable planets in the solar system. Temperatures on its surface get up to four hundred degrees Celsius (hotter than Mercury). Venus is about sixty million miles from the sun and takes about 240 days to orbit the sun. Venus is unusual in that it's the only planet that rotates from West to East and has no moon that we have found!
3. Earth. At ninety three million miles the distance of Earth from the sun is called an Astronomical Unit (AU) and is used to record the distances from the sun for all the planets (Mercury is .4, Venus is .7 Earth is 1 AU)
4. Mars. The Roman god of war is a red planet that Ancient men always saw Mars as the 'god' of the warrior. Mars is 1.2 Astronomical Units (AU) or one hundred and twenty million miles from the sun and takes three years to make a full orbit.
5. Jupiter. Was the chief 'god' in the Roman pantheon. Jupiter moves between 4.9 AU (500,000,000 miles) and 5.2 AU (550,000,000 miles) It is about eleven hundred times the size of the Earth and two and a half times the size of all the other planets in the solar system combined, it takes eleven years to orbit the sun.
6. Saturn. Another Gas giant. Saturn and Jupiter are the 'big boys' of the solar system that help protect the smaller inner planets from meteorite or comet strike. Saturn is 10 AU (600,000,000 miles) from the sun and takes 26 years to orbit the sun.
7. Uranus. Was the first planet that was found in relatively modern times. Uranus orbits about 19.2 AU (2 billion miles) from the sun and takes about 84 years to orbit the sun. Uranus actually rotates at a very steep incline that makes it's seasons literally last twenty years!
8. Neptune. The Roman god of the sea Neptune is the last of the fully fledged planets in the system. Neptune and Pluto are the only two to be predicted using mathematical calculations. It's a whopping 30 AU (that's thirty times the distance of the Earth) from the sun (about 3.500,000,000 miles) from the sun orbit and takes about 164 years to orbit the sun
9. Pluto. Roman 'god' of the underworld Pluto is furthest out. the orbit is actually more like an egg in shape that swings between 39 AU (about four billion miles) and 49 AU (about 5.5 billion miles from the sun and takes 250 years to orbit the sun.
Pluto is a long way from the sun and what's strange is that all the other planets orbit on a plane, but tilt that plane by about 30 degrees and that's where Pluto is.
Look around the solar system
Our Solar System
Why did we go?
After the initial disovery interest was lost in Pluto until the 1970's when things started to be noticed. Pluto was thought to be just a frozen rock out in space with very little relevance, then Charon was discovered.Charon is Pluto's biggest Moon (at the time it was the only Moon we knew about and it was roughly half the size of Pluto)
At last we could use Charon to compare and find out how small Pluto actually was and it was a disappointing one fifth the size of the Earth, still big enough that it's own gravity pulled it into a sphere but not much more and probably no atmosphere!
By the 1980's Pluto was on it's way into the Solar system (actually on it's way nearer than it had been for two hundred years!) and scientists started to notice some things that shouldn't be there! Scientists had thought that Pluto had no atmosphere but all of a sudden they saw that there was gas (Methane) on Pluto and it was losing the gas at incredible speed. instruments were pointed at the planet and it was discovered that Pluto actually had an atmosphere but it was frozen! Literally a blanket of frozen Methane covered the planet!
What was found
Only slightly larger than the average fridge the New Horizons spacecraft has been on it's way to Pluto since 2006 when it was launched. But the planning for the mission goes back to around the early 1990's when NASA was looking for ways to explore the solar system 'on a budget' (if you call half a billion dollars that!)
But the goal has always been to try and answer some of the Comets questions that have plagued scientists since the first theories of how the universe and solar system were formulated. They hoped that by sending a craft out to the furthest reaches of the solar system they'd get answers.
1. If the solar system is 4 billion years old then why do comets still have tails? Comets are covered with ice, as they come in towards the sun they shed the ice in space, that shedding of the ice causes the 'tail' of the comet, as the comet journeys through the system it loses it's ice. By now the comets should have lost all the ice so if the solar system is that old then there has to be a place where the ice is replenished!
2. How can Pluto be 4 billion years old and still losing it's atmosphere? it should have been gone billions of years ago!
3. How dense is the Kuiper Belt?
By 2006 bodies had been discovered in the Kuiper Belt that forced the international Astronomical society to ask what a 'planet' really is? Four other small 'planets' had been discovered that threw the whole idea of what a planet is into question.
They settled on three criteria
- It orbits the sun
- It's massive enough that it's own gravity pulled it into spherical shape
- It is big enough to clear it's orbital path of all debris
Pluto qualifies on two of these counts, but it's in the middle of the Kuiper Belt, a debris field that it shares with three other objects, Eris is bigger than Pluto (but not as dense) Haumea and Makemake are also there with Sedna even further out. All these were found since 2006!
New Horizons mission was to go an literally take a look at some of these bodies and see what it can tell us.
And what it has told us has blown scientists away!
The new story
Pluto, it turns out is a young planet! At least it's surface is young! Scientists expected to find a scarred shell of a planet beaten by meteors and comets, what they've found is a planet that is amazingly young looking!
Look at the pictures of the planet, you'll see whole large areas that are smooth looking! That's because there are no impact craters there! Somehow the planet is either a lot younger than thought or it's able to renew it's crust! At the moment no one is sure which it is!
The frozen atmosphere is a lot thinner than expected. it turns out that Pluto has an atmosphere of Methane, Nitrogen and Carbon Monoxide and Pluto's atmosphere is being vented much faster than previously thought! It's losing Methane and Nitrogen at the rate of 500 tons per hour! and the gas is escaping at speeds faster than sound can travel!
By comparison Mars is much bigger and is losing it's atmosphere at the rate on 1 ton every hour. Mars' atmosphere is so thin it's like being at the edge of the Earth's atmosphere!
If Pluto was 4 billion years old then that atmosphere should have been lost billions of years ago! but it's still there and still escaping! How?
Mountains of Ice! And I literally mean MOUNTAINS 11,000 feet tall and up to 100 miles long! And all this should not be there if the planet was as old as it's supposed to be!
From here to Eternity?
New Horizons is actually powered by a small Nuclear reactor on board (not the propulsion system but the instruments) that can run for up to 35 years so the scientists are hoping to send it farther out into the Belt to see what's out there, they have some ideas what they want to go look at but said that the decision wouldn't be made until after the Pluto visit and then they'd approach NASA for funding to keep the mission going (I mean they've got the craft out there so why not) in the hope of unlocking some of the mysteries of our neighborhood.
So far the ship has traveled 4 billion miles to get where it is now and is traveling at around 50,000 miles an hour but the next leg of the journey the scientists say will take two years but that's OK as they also say it's going to take those two years to work out what answers New Horizons sent back from Pluto!
Latest update (23/8/15)
Okay I used the European way of dating this with the day at the beginning! The team at New Horizons are studying the data that they now have from the spacecraft and they've already come to some conclusions.
Firstly the surface seems smooth because it is being renewed from within the dwarf planet! that means that somewhere inside there is a heat source keeping the Nitrogen above it's freezing point and every so often it is erupting like a Geyser and freezing at the same time as it erupts where it then settles on the surface and melts again only to vent into space at the rate of about a thousand tons every hour!
They ruled out meteor strikes as the source as the data indicates that Pluto doesn't get anywhere near as many as would be needed to replenish the Nitrogen, the question now is how does a place so small store so much Nitrogen that it can keep doing this for the seeming billions of years?
Pluto is regarded as too small to have Nuclear reaction going on to generate the heat needed for this so we still have a lot of unanswered questions, but we'll keep looking.
Where to now?
Just a few weeks ago the folks from NASA finally got to sit with the team from New Horizons and plan the next part of the journey. There was always going to be a 'next part' with the way the spacecraft was built but at the time they were thinking about so many things that the decision of where to after Pluto was left until after Pluto!
At the time of the Launch we were only just finding out about some of the bodies 'out there' and what we were finding out was blowing the science community away so they had so much to think about that they just couldn't commit to anything.
To date the furthest object out that we know about is a dwarf planet that has been named Sedna after one of the Norse gods and it's literally twenty times further from the sun than Pluto is (and that's at it's closest point!) It takes about ten thousand years to orbit the sun and even getting close to it is way beyond anything we can hope to achieve in the next hundred years!
Five possibilities were identified in 2010 but only three were given serious consideration, the problem was that even the closest one is a further billion miles from the sun and will take two years for the little craft to get there, It's called 2014MU69 (a really good name for a mission?) an asteroid about 40 miles across and thought to be about 15 miles wide. There were a number of other contenders but the final destination had to take into account the fuel that the little craft can carry and what if can do when it gets there.
The asteroid as another 1 billion miles further out than Pluto and it'll take at least two years to get there. New Horizons is expected to arrive around January of 2019 but all that is subject to NASA actually getting funding for the mission as the funding isn't due to be discussed until next year! The reason for the decision now is simply by 2016 it would be too late to make the course corrections necessary for the trip.
Good luck and Godspeed little ship.
Take a ride with NASA
I think God must be Jewish!
I don't mean it in a nasty way but as I read my Bible and as I remember from my time in the Middle East I see that the Eastern way of answering a question was with another question! Jesus did it all the time, and as I look at the data that the team from New Horizons has put out it's almost as if we went out there to ask questions of the cosmos only to get answers back in the form of more questions!
Example of what I mean
Q How old is Pluto?
A Either I'm not very old (100,000,000 years was the figure they said) or I'm renewing my crust in some way you've no idea how so you work it out! (or both!!)
Q If you're so old Pluto then how come you still have an atmosphere?
A It's frozen most of the time. But I'm still losing it much faster than you thought! (you knew it was frozen but not how fast I can shed it when it's defrosted!)You work it out!
Only one thing is sure and that is that Pluto is throwing up more surprises than anyone thought possible and the scientists are having great fun trying to work the answers out.And all from a dwarf that everyone thought would be a boring place!