By Bethan Evans, Gwen Jackson, Siobhan Waters and Amy Folkard –

the astronomers of Year 9, LGGS

Gilese 1214b The reason we chose Gilese 1214b is because it is perfect for human existence. It has a suitable:-Gravity score-Atmosphere-Density / terrain -Goldilocks zoneWe also had to consider other things before making our decision, such as:-How to detect an Exoplanet-The effect on the body-Other aspects we need to know about Gliese 1214b-What if the planet is already inhabited? -

Now that we know what an exoplanet is, the next problem is Now that we know what an exoplanet is, the next problem is to find one. This is a very difficult process, seeing as planets to find one. This is a very difficult process, seeing as planets

do not emit any light of their own. So we cannot look for one do not emit any light of their own. So we cannot look for one simply by looking through a telescope, partly because they simply by looking through a telescope, partly because they are so far away and partly because of the fact that, unlike are so far away and partly because of the fact that, unlike stars, they do not emit light, they only reflect it so are just stars, they do not emit light, they only reflect it so are just about invisible because it is impossible for even out most about invisible because it is impossible for even out most

powerful telescopes to differentiate between the light of a powerful telescopes to differentiate between the light of a star and the light reflected by a planet.star and the light reflected by a planet.

We have many different methods of detecting We have many different methods of detecting exoplanets. For example, the Optical Gravitational exoplanets. For example, the Optical Gravitational

Lensing Experiment group (OGLE) are Lensing Experiment group (OGLE) are experimenting with one type of detecting planets experimenting with one type of detecting planets which takes the theory behind its method from which takes the theory behind its method from

Einstein’s General Theory of Relativity. Einstein said Einstein’s General Theory of Relativity. Einstein said that massive objects in space can bend light on its that massive objects in space can bend light on its

way to Earth. This is just one way of detecting way to Earth. This is just one way of detecting massive exoplanets.massive exoplanets.

The Transit Method uses the moments during which a The Transit Method uses the moments during which a planet passes directly between its star and our Earth. It is planet passes directly between its star and our Earth. It is the most successful way of finding a planet yet found, and the most successful way of finding a planet yet found, and has helped to discover most of the planets which we have has helped to discover most of the planets which we have found so far. For example, Gilese 1214B was found using found so far. For example, Gilese 1214B was found using

this method, so we know that it has been practical in this method, so we know that it has been practical in finding the exo-planet which is most important to us in finding the exo-planet which is most important to us in

this investigation.this investigation.

An example of transits closer to home is the transit An example of transits closer to home is the transit of Venus which happened in the summer of 2012. of Venus which happened in the summer of 2012.

This was one of the few transits of Venus which we This was one of the few transits of Venus which we will be able to see – they happen in pairs, and the will be able to see – they happen in pairs, and the

next won’t happen until 2117! An extreme next won’t happen until 2117! An extreme example of a transit is a solar eclipse. This happens example of a transit is a solar eclipse. This happens when the moon passes directly between the Earth when the moon passes directly between the Earth and the Sun and completely blocks the Sun’s light.and the Sun and completely blocks the Sun’s light.

Obviously the transits which we are trying to detect are nowhere Obviously the transits which we are trying to detect are nowhere near as obvious as the closer-to-home transits. In fact, trying to look near as obvious as the closer-to-home transits. In fact, trying to look

for a planet using the transit method is like trying to detect a fly for a planet using the transit method is like trying to detect a fly flying in front of a lamppost by looking at the light it blocks out – flying in front of a lamppost by looking at the light it blocks out –

when standing a kilometre away! The only way we can tell that they when standing a kilometre away! The only way we can tell that they are there is by looking for regular dips in the light emitted by the are there is by looking for regular dips in the light emitted by the

star that they orbit. We can use the size of these dips and the star that they orbit. We can use the size of these dips and the amount of time between them to help estimate the size and orbit amount of time between them to help estimate the size and orbit

length of the planet we have detected. If they appear enough times, length of the planet we have detected. If they appear enough times, at constant intervals and sizes, then we can assume that we have at constant intervals and sizes, then we can assume that we have

found a new planet.found a new planet.

We set up an experiment to investigate the transit We set up an experiment to investigate the transit method for ourselves. This experiment used method for ourselves. This experiment used

polystyrene balls as planets and a light bulb for a polystyrene balls as planets and a light bulb for a star, and showed us the ideas behind the transit star, and showed us the ideas behind the transit

method.method.We ended up with four different graphs telling us We ended up with four different graphs telling us about the transit method, which will be explained about the transit method, which will be explained

in the next few slides.in the next few slides.

Graph 1 – Smaller Planet, Middle Distance from the Planet, 5 second Intervals.The dips in the amount are quite big, because as it is further away, the planet blocks out more light. Also, their frequency is smaller than when the planet was closer to the star.

Graph 2 – Smaller Planet, Close to the Light Source, 2 second IntervalsThis time the dips are smaller because the planet is close to the light source, and more regular because the intervals were smaller.

Graph 3 – Bigger Planet, Middle Distance from Light Source, 5 second IntervalsOn this graph, the dips are very big compared to the other graphs. This is because the planet is big and far away.

Graph 4 – Bigger Planet, Close to Light Source, 1 second IntervalsAltogether from this experiment we can find out that the bigger the planet, the bigger the dips in the amount of light. Also if it is far away from its star then it will often block out more light than if it is closer.

Calculating the Habitable Zone of Gilese 1214

Inner Boundary Outer Boundary

We then compared this to the semi-major axis of the planet in We then compared this to the semi-major axis of the planet in question. The semi-major axis of a planet is a way of question. The semi-major axis of a planet is a way of measuring how far a planet is from its star so that this measuring how far a planet is from its star so that this measurement is fair. The semi-major axis of Gilese 1214b is measurement is fair. The semi-major axis of Gilese 1214b is 0.0143, which is between the two values worked out above – 0.0143, which is between the two values worked out above – which means that Gilese 1214b is within the Habitable Zone!which means that Gilese 1214b is within the Habitable Zone!

We can work out a planet’s atmosphere using what is We can work out a planet’s atmosphere using what is called a spectroscope. These instruments are used by called a spectroscope. These instruments are used by

astronomers to help figure out which chemicals can be astronomers to help figure out which chemicals can be found within a planet’s atmosphere, using the light which found within a planet’s atmosphere, using the light which

passes through it. For example, the Earth’s atmosphere passes through it. For example, the Earth’s atmosphere contains a lot of nitrogen, and enough oxygen for we contains a lot of nitrogen, and enough oxygen for we

humans to survive, as well as other elements. Without this humans to survive, as well as other elements. Without this atmosphere the Earth would be unable to sustain life.atmosphere the Earth would be unable to sustain life.

The spectroscope relies on the fact that white light The spectroscope relies on the fact that white light can be split up into a whole spectrum of rainbow can be split up into a whole spectrum of rainbow

colours. For example, a rainbow as we see it in the colours. For example, a rainbow as we see it in the sky is made when raindrops split up the sun’s ‘white sky is made when raindrops split up the sun’s ‘white

light’ into the visible spectrum.light’ into the visible spectrum.

Certain elements which can be found in a planet’s Certain elements which can be found in a planet’s atmosphere absorb certain colours of light. For atmosphere absorb certain colours of light. For

example, you would be able to tell if sulphur is in a example, you would be able to tell if sulphur is in a planet’s atmosphere because it absorbs a certain planet’s atmosphere because it absorbs a certain

type of yellow light. Each element has its own type of yellow light. Each element has its own specific type of light, which is very useful for specific type of light, which is very useful for

detecting them in a planet’s atmosphere.detecting them in a planet’s atmosphere.

So when we look at the spectrum of light which is So when we look at the spectrum of light which is passing through an exoplanet’s atmosphere, we passing through an exoplanet’s atmosphere, we can see tiny scratches where there are types of can see tiny scratches where there are types of

light being blocked. These can also be transferred light being blocked. These can also be transferred to graphs, which show dips in the light which is to graphs, which show dips in the light which is

passing through a planet’s atmosphere.passing through a planet’s atmosphere.

This is calledThis is calledATMOSPHERIC ATMOSPHERIC

DISTORTIONDISTORTION

We have used this method to work out that the atmosphere of We have used this method to work out that the atmosphere of Gilese 1214b would be suitable for life, which means that we Gilese 1214b would be suitable for life, which means that we are one step closer to having a planet which we could live on.are one step closer to having a planet which we could live on.

Without a suitable atmosphere, a planet would be completely Without a suitable atmosphere, a planet would be completely unsuitable for life. Our Earth’s atmosphere currently protects us unsuitable for life. Our Earth’s atmosphere currently protects us from harmful sunrays, makes sure that water on Earth is kept on from harmful sunrays, makes sure that water on Earth is kept on

Earth and generally makes the planet suitable for life.Earth and generally makes the planet suitable for life.

Venus, however, has an extremely dense atmosphere which Venus, however, has an extremely dense atmosphere which would crush anyone who tried to go there, and Mars has little to would crush anyone who tried to go there, and Mars has little to

no atmosphere, meaning that all water on Mars would not be no atmosphere, meaning that all water on Mars would not be sustained.sustained.

So both of these planets, which are quite like Earth, would be So both of these planets, which are quite like Earth, would be unsuitable for life, and atmosphere plays a big part in this.unsuitable for life, and atmosphere plays a big part in this.

Gravity is vital to survival on an Gravity is vital to survival on an exoplanet. If there is too much gravity we exoplanet. If there is too much gravity we will be flattened against the surface but if will be flattened against the surface but if

there is too little we will float. We can there is too little we will float. We can work out the Gravity Score with the work out the Gravity Score with the

formula: Gravity Score = mass/radius formula: Gravity Score = mass/radius squared. The Gravity Score of Gliese squared. The Gravity Score of Gliese

1214B is 0.9133140836.1214B is 0.9133140836.

Density is very important when you are Density is very important when you are trying to find out if a planet can support life. trying to find out if a planet can support life.

If it is not dense enough your will fall through If it is not dense enough your will fall through it but if it is too dense you won’t be able to it but if it is too dense you won’t be able to

walk on it. To find out how dense Gliese walk on it. To find out how dense Gliese 1214B was, we used the method 1214B was, we used the method

Mass/Volume = Density. The density of our Mass/Volume = Density. The density of our own planet, Earth, is 5.5 g/cm3. Gliese own planet, Earth, is 5.5 g/cm3. Gliese

1214B’s density is 1870 kg/cm-31214B’s density is 1870 kg/cm-3.

If we get to Gliese 1214b and find out that it is already If we get to Gliese 1214b and find out that it is already inhabited by aliens, what would be the protocol? inhabited by aliens, what would be the protocol?

Well you would have to approach them with respect and gifts, Well you would have to approach them with respect and gifts, to try and make peace with them so we can live together. As to try and make peace with them so we can live together. As Gliese 1214b is so much like earth and human can survive on Gliese 1214b is so much like earth and human can survive on it, hopefully the aliens should be just like us. This means they it, hopefully the aliens should be just like us. This means they may have enough intelligence so that we can communicate may have enough intelligence so that we can communicate

with each other successfully. We could share our knowledge with each other successfully. We could share our knowledge with each other, to widen our knowledge of the universe. with each other, to widen our knowledge of the universe.

Even though we are evacuating everyone (hopefully) we still Even though we are evacuating everyone (hopefully) we still might not be able to bring all of our traditions and agriculture might not be able to bring all of our traditions and agriculture

with us.with us.

… … so as a solution we will bring with us many things to remind us so as a solution we will bring with us many things to remind us of our old ways and so we can teach the aliens as well.of our old ways and so we can teach the aliens as well.