Download Does the Galaxy need guarding

Does the Galaxy
need Guarding?
Number of Habitable Exo-Planets.
How to find Exo-Planets.
Alien Life.
Travelling to Exo-Planets.
Big Question 1.
Are there other Earth-like planets in our universe?
There are many planets in the
Guardians’ universe. The Nova
Empire home world of Xandar
in the Andromeda Galaxy is
very Earth-like. The big
question is how many planets
Planet Xandar [A]
and ‘Earth-like’ planets could there be in our Galaxy and the rest of the
universe?
How many Stars the there?
Astronomers estimate that the Milky Way (our Galaxy) has around 400,000,000,000
stars (400 billion) [1] and about a trillion stars in the Andromeda galaxy.
There are an estimated 100 billion galaxies in the known universe [2].
Which leads to an estimate in the magnitude of 10,000,000,000,000,000,000,000
stars in the known universe [2].
How many Stars have planets?
Current evidence suggests that on average every star has
at least 1 planet orbiting it. Although you don’t tend to
get just one planet forming around a star, so it is likely
that the number of planets is 5 to 10 times the number of
stars [3].
Exo-planet[B]
So that puts an estimate of between 2,000,000,000,000
and 4,000,000,000,000 planets in our galaxy and
something possibly around
100,000,000,000,000,000,000,000 planets in the known
universe.
How many of the planets could possibly support life?
Observations during 2014 show that at least 25% of the red dwarf stars have Earth
sized or super-Earth sized planets orbiting in their habitable zone [4]. In 2014 there
are 21 recorded planets that have a chance of supporting life as we know it [5]. We
still need to learn more about their environments as there is a lot more that a planet
needs than just to be within the habitable zone.
Big Question 2.
What does a planet need in order to support life?
Morag is one of the least hospitable
planets in Guardians of the Galaxy,
but life still exists there. So what
does a planet actually need in order
to support life?
 A solvent
Morag [C]
Water is a vital component of all life on Earth and also allows life to form by being a
solvent , however it is possible that alien life could use a different solvent like
ammonia or methane.
 Temperature
The planet needs to be in the habitable zone around a star where it is at a
temperature where water can be in liquid form. Although if it uses another liquid or
has a thick atmosphere it could be at temperatures outside what we believe is within
the habitable zone.
 Protection / atmosphere
The Earth’s atmosphere does two important jobs for us, it keeps water evaporating
into space and it blocks most of the harmful parts of the Sun’s rays from reaching
Earth. The same job could be performed by ice. A planet might have liquid trapped
below a sheet of ice. This would also provide gases needed for life.
 Elements
Life on Earth is Carbon based, but we also need and use many heavier elements,
which are believed to come from early asteroid impacts and from heavy atoms
produced in supernovas. Therefore the planet would have need to collect a good mix
[6]
of elements.
 Some of the other possibly important factors.
The Moon: Keeps our axis stable to give regular seasons.
Outer Planets: Deflect dangerous comets protecting earth.
Magnetic field: Protects Earth from solar winds.
Plate tectonics: This is actually about keeping the balance of C02 and temperature.
Surprisingly Oxygen isn’t necessarily needed for life. It is a theory that early on
organisms on Earth actually produced Oxygen and did not need it.
Big Question 3.
How many planets do we know of that might support life?
 Habitable planets so far.
We have found around 50 planets so far (2014)
that are witin a habitable zone of a star . Around
10 of these planets have a confirmed status as
being likely habitable planets [7]. All of which
are in our Galaxy, the Milky way. Most of the
Guardians of the Galaxy story takes place in one
of our closest neighbour galaxies Andromeda.
Andromeda Galaxy [D]
 Have we found them all in our galaxy?
Almost 2000 planets in our galaxy have been discovered so far (habitable and nonhabitable), but this number is increasing all the time.
This means though that roughly 1 in 40 of the planets we have found is a potentially
habitable planet.
 Does that mean 1 in 40 of all the planets will be habitable?
Probably not. The current methods of detecting planets in our galaxy are better at
finding certain types of planets and don’t yet find every planet that orbits a star. Also
most planets we have detected so far are within 1,000 light years, the Milky Way is
100 times wider than that. Andromeda is 2.5 million light-years away and we can’t
yet detect planets that far away.
Both star wobble and the transit method for detecting planets require the planet to
be orbiting flat compared to earth. Gravitational lensing and direct imaging can
detect planets with other orbit orientations.
If the current methods were used on our solar system from elsewhere in the galaxy
we would most likely only find Venus, Earth and possibly Jupiter.
‘Edge-on’ orbit; All
methods can detect.
Flat orbit: Only Gravitational
lensing and direct imaging.
Real Exo-planet - Gliese 581c
GotG planet – Morag
[E]
[C]
22 light years from Earth, the Star Gliese
581 has three confirmed Exo-planets
orbiting it (b, c and e). Of the three ‘c’ is
the most ‘Earth-like’ with temperatures
predicted to be between -3 and 40 OC.
581c takes just 13 Earth days to orbit
Gliese 581.
The once populated planet of Morag is
now a rather geologically unstable planet.
Still technically capable of sustaining life,
but now only inhabited by lizard like
creatures called Orloni and other lower life
forms.
Real Exo-planet - Gliese 832c
GotG Location – Nowhere
At a distance of 16.1 light
years the red dwarf star
Gliese 832 host a planet
(Gliese 832c) which is
believed to be the closest
[F]
‘habitable’ planet to Earth.
Gliese 832c has a mass 5.4 times that of
Earth and so would have higher gravity. This
means it probably has a denser atmosphere
than Earth and would then be warmer due
to greenhouse effects.
Nowhere Is the head of a long dead Celestial
being. Celestial beings are the most ancient
known race of the Marvel universe and are
responsible for most alien life and superpowered beings including the X-gene.
Real Exo-planet – Kepler 22b
GotG planet – Xandar.
Kepler 22 is a
slightly smaller star
than the Sun about
620 light years
away. It has one
known Exo-planet.
[G]
Kepler 22b orbits its star in 290 earth days
within its habitable zone. It has a mass 2.4
times that of Earth. It is thought to be an
ocean rich planet.
[H]
[A]
Home to the intergalactic police force, the
Nova Corps. Xandar is very Earth-like and
has large oceans with constructed/
modified islands. The main city’s shape is
modelled on the Nova Corps logo.
Method 1.
Star wobble.
A planet orbits a star because of the star’s gravitational pull, but a star also
experiences an equal and opposite pull from the planet’s gravity. This
causes the star to wobble (shift back and forward) as the planet orbits it.
So if a star is wobbling we know a planet must be orbiting it.
How is the ‘wobble’ detected?
If an object is moving away the light waves it gives out are ‘stretched’ and
have an increased wavelength (with a lower frequency). This is called Red
Shifrt. Similarly if an object moves towards an observer then the wavelength
is shortened (and has a higher frequency). This is called Blue Shift.
Star Movement
When a light wave is lengthened the colour becomes more red and
becomes more blue when it is shortened.
This shift in colour is detected and the frequency of the shift is used to
determine the orbit period and the orbit radius of the exoplanet. The
amount of red shift that occurs can be used to find the mass of a
exoplanet.
Calculating the orbit distance.
An orbit depends on the force acting on the orbiting object. The force
depends on gravity.
Orbit speed formula: 𝑭 =
𝒎𝒗𝟐
𝒓
Force due to gravity formula: 𝑭 =
𝑮𝑴𝒎
𝒓𝟐
Replacing v with 2πr/T (orbit radius / period of orbit) and combining the
two formulae we get an equation known as Kepler’s (third) law.
𝟐
𝟒𝝅
𝑻𝟐 =
𝒓𝟑
𝑮𝑴
Kepler’s law gives the exact orbit radius of a planet (r) based on the period
of its orbit (T) (found from the star wobble) and the mass of the star (M).
Method 2.
Transit.
If an exoplanet crosses in front of a star it blocks out
light. This can be detected from earth as the change
in brightness of a star.
Brightness
Kepler’s Law.
Time in hours
[I]
𝟐
𝟒𝝅
𝑻𝟐 =
𝒓𝟑
𝑮𝑴
If dimming is detected at regular intervals and for a fixed time then the
orbit time (period) of the exoplanet can be calculated. Once the period of
the orbit is known the orbit radius can be calculated using Kepler’s law
(just like the wobble method).
The size of a star can be accurately calculated from the spectrum it gives
off; the size of the exoplanet can then be calculated by the amount of
dimming that occurs.
Combining this information on the size of the exoplanet with the mass of
the exoplanet from star wobble, the density can be calculated. This helps
give an idea of what it is made of.
Limitations.
A transit is a rare event and requires an exoplanet to pass between the star
and the Earth. It means its orbit must be almost exactly ‘edge-on’ to Earth.
It is often a very subtle change in the brightness of a star, it takes very
sensitive equipment which is normally very accurate, however, even with
this equipment there have been a number of examples of false results.
[8]
Method 3.
Gravitational microlensing.
Microlensing requires a unique event that can only be observed once and
does not repeat itself. It requires one star to pass exactly behind another
in line with earth.
Under the influence of gravity light is bent very slightly, much like light
refracting through a convex lens. This becomes more obvious over large
distances and means that microlensing allows us to find exoplanets at
huge distances (10,000 light years) away. However the distance is not
always accurately known and can be 1000 light years out.
Lensed Images
Source star
Lensing star
and planet
Observatory
Brightness of the
Lensing star
As the source star moves behind the lensing star it creates two distorted
images of the star that then stretch into a full ring around the lensing star
(called an Einstein ring). When this happens the brightness of the lensing
star spikes (up to 100 times as bright). If there is a exoplanet near the star
it creates another image of the star as it passes and temporarily increases
the brightness. A microlensing event can last weeks or months, the blip in
brightness caused by a exoplanet lasts a few days.
Brightness spike from the
source star and lensing star.
Brightness spike
from a planet.
Time (days)
[9]
Method 4.
Direct imaging.
Taking a picture of a distant exoplanet is very difficult because an
exoplanet is very faint compared to the star it orbits.
There is a relatively simple method that allows exoplanets to be seen more
clearly. This is to shape/block out the light of the star so the dimmer
exoplanets orbiting it can be seen. This method is called coronography.
Sunshade
Star
Telescope
Exoplanet
The other method to block the light from a star is to combine images of
the star from multiple telescopes in a way that the light from the star
destructively interferes with itself (cancelling out the light). This method is
called interferometry.
+
Two telescopes receiving
the light of the star and
exoplanet
=
When two waves from the same source
arrive ‘out of phase’ they cancel each
other out (destructive interference).
While most people know about the Hubble telescope, there are around 30
space based observation satellites looking out into space. Evidence of
exoplanets has been gathered by these satellites as well as a larger
number of Earth based observatories.
One of the better know space telescopes looking for exoplanets is the
Kepler telescope which has gathered evidence to confirm 100s of
exoplanets.
A list of observation stations can be found at: http://exoplanet.eu/research/
Alien Life – the building blocks
The Marvel universe is filled with
diverse forms of life from the
humanoids (Nova and the Kree),
symbiotes (Venom and Carnage)
to intelligent plant life like Groot.
The big question though is how does different life begin?
[J]
What do you need for life?
The short answer is amino acids.
Amino acids are chemical compounds that form
proteins. Proteins give cells their structure and are
involved in all of the processes in cells and living
bodies.
Glycine, a amino acid
There are only 20 naturally occurring amino acids, however amino acids join in unique
long chains to form different proteins.
Can an amino acid form naturally?
Yes. Experiments have shown that simple chemicals like ammonia, methane and
hydrogen can, with heat and pressure, naturally form into amino acids. Bob Hazen
began experiments in 1996 using ‘an extreme pressure cooker’ to form amino acid,
sugars and other organic compounds[10]. The conditions Hazen produced occur
naturally in deep ocean trenches where geothermal activity provides the heat
needed.
Some other ways organic compounds could naturally form.
Electrical sparks – An experiment by Miller and Urey in 1953 suggested that lightning
could have created the key building blocks to life.
Community Clay – Alexander Graham Cairns-Smith suggests that minerals in clay can
arrange themselves into organic patterns.
In the atmosphere – Some theories suggest that organic compounds can form in the
atmosphere and are rained down into oceans.
Are we all aliens? Life could have come from elsewhere in the galaxy hitchhiking on
comets from other star systems. Alternatively as in the case of the marvel universe
from some meddling ancient celestial beings.
[11]
Alien Life – the next steps
What happens once Amino Acids are formed?
The first evidence of life is microbe-like cellular filaments that have been found in 3.5
billion year old rocks. The question is how do you go from organic compounds like
amino acids to a cell?
Step 1 - formation.
Simple organic molecules (once formed) join together to form longer more complex
chains.
Step 2 - Replication.
Reproduction is a key feature of life. Biologists believe that the first molecules to selfreplicate were RNA molecules. There is a recognised evolutionary era, referred to as
the ‘RNA world’ in which RNA did everything and was a precursor to DNA.
RNA (ribonucleic acid) is a nucleic acid (like DNA) that is present in all living cells. It
acts as a messager, carrying instructions from DNA, controlling protein synthesis.
Some viruses still use RNA rather than DNA to carry their genetic information.
Step 3 - Cells.
Evolution of a membrane would have meant that the RNA was more protected and
able to replicate without interference from its surroundings. So ‘encased’ replicators
(or early organisms) would out compete ‘naked’ RNA replicators.
Step 4 – Modern metabolic processes.
RNA would have slowly given way to other types of
molecules for different functions. DNA would become the
main genetic material. It is more stable and efficient at
making proteins. DNA-containing cells would have had
many advantages over RNA-containing cells and would have
out-competed them.
Step 5 – Multicellular.
An estimated 2 billion years ago some cells
evolved functions that kept them together to
form multicellular organisms. One example is a
1.2 billion year old algae found in fossils.
[12]
Alien Life – Is there evidence on other planets?
Most of the Marvel universe life forms are from well outside our solar
system and galaxy. NASA, however, is looking for signs of life in our solar
system. There are a number of possible candidates for organic molecules
on other objects in our solar system: Mars being the first, but more likely
some of the moons of our outer planets like Europa and Titan.
Mars.
NASA has had their Curiosity rover rolling around
on Mars since August 2012. So far it has found no
real evidence of life itself, but it has some
evidence that there might have once been
conditions suitable for life.
Europa.
Europa is a moon of Jupiter visited by NASA’s Galileo
spacecraft (which took the picture to the right). The
photos and data from Europa show a huge likelihood
of water and minerals required for life.
Titan.
[K]
Saturn’s moon Titan has turned up evidence for
organic molecules in its atmosphere. Both NASA’s
Cassini spacecraft and the Atacama Large
Millimetre/sub-millimetre Array (ALMA) have
detected organic molecules in Titan’s atmosphere.
[13]
Titan is considered to be the most Earth-like body
[L]
in the solar system. It has plenty of water in lakes
and seas as well as a thick atmosphere. However due to its distance from
the Sun it is a lot colder than Earth at minus 179 degrees Celsius.
Alien Life – Where are they?
Enrico Fermi proposed (in conversation at lunch) that if there was intelligent life in
our universe we should have heard from them by now. So if we haven’t heard from
them does that mean they are not there? (Fermi Paradox)
You can argue about the distances of space and travel and signal speed, but for the
age of the universe the time differences become insignificant. If something intelligent
is out there we should have heard or seen something. [14]
Solutions to Fermi’s Paradox.
The main solutions revolve around a few key ideas;
1. It isn’t easy for life to start and then evolve to a technologically advanced level, so
we are quite probably the only ones in the galaxy.
2. Advanced civilizations destroy themselves in short time scales.
3. Planets that have survived the dangers of space with the right conditions and
resources for life are rare.
Some weirder solutions to Fermi’s Paradox:
The Zoo Hypothesis: Aliens already know we are here and for
whatever reason prefer to watch from afar (probably for
entertainment or study). We are monkeys in some kind of
cosmic cage. Much like the ancient Watchers of the Marvel
universe who watch and very infrequently intervene.
A Watcher[O]
Self-imposed quarantine: Space is dangerous, alien life could
be dangerous, so why not just stay home and keep to
yourselves? This is quite possibly what intelligent alien life has
decided. Deciding to stay home and look after themselves
might be preferable to risking the perils of deep space.
Galactic Council[P]
The Whack-a-Mole Hypothesis: a bit like the zoo hypothesis,
intelligent life is watching us waiting to see how we turn out:
if things go bad, they take action. This is most like the Marvel
Earth-616 universe in which Earth is declared off limits by the
Galactic council as Humans are considered unpredictable
and dangerous.
We don’t know what you’re saying! What are the chances that alien life
communicates the same way we do? Maybe we just don’t understand the messages
that are already coming our way.
[15]
Space Travel – How far can we get?
Peter Quill’s Milano is the muscle car of
spaceships, but unless it is equipped with
some kind of space bending ‘faster than
light’ system (FTL) it would still take a long
time to travel between planets.
The fastest object humans have put into
space was a solar probe which achieve a
velocity of close to 200 km/sec. At that speed
it would take about 8.5 days to travel the
149,600,000 km to the Sun and about 1 year
to get to Pluto.
Energy
How fast can we go?
Speed
of
light
The closest star is Proxima Centauri, located
just a short 4.24 light-years (4.01 × 1013 km)
Speed
away. It would take the solar probe over
6000 years to get there. The closest potentially habitable planet we have found is
11.9 Light years away, which would take us 17,800 years to get to at current speeds.
Just go faster!
Even at the speed of light that is still 11.9 years to get to the closest ‘potentially’
habitable planet. The problem with getting to light speed is that the energy required
to reach it becomes infinite. Basically, there is not enough energy in the universe to
accelerate an electron to the speed of light.
Light is the fastest thing in the universe because it doesn’t interact with the Higgs
field and so can go as fast as possible. Why not any faster? The speed of light is a
fundamental universal constant like the gravitational constant or the charge on an
electron and so it cannot be increased.
Warp speed!
So is the best we can hope for longer than 12 years to the nearest habitable exoplanet? Maybe not, there are some theories on faster than light travel that involve
space time bubbles etc... NASA is ‘working’ on one such idea that would shorten year
long trips to a day.
Space Travel – Other difficulties of space travel?
Peter Quill (although you might know him by
another name - Starlord? ) has a mask that allows
him to survive in the vacuum of space. This could
actually work if it is an airtight seal. His only other
problem would be radiation. So as long as he has
protective clothing he would be safe for a short
period of time, however, spending a long time in
space provides more health and survival difficulties.
Some of problems faced in space travel.
Oxygen is our first and possibly most pressing need. Oxygen can be produced from
electrolysis of water, splitting water into hydrogen and oxygen. Ultimately it would be
better to use plants to recycle CO2 humans breathe out into oxygen. Air also needs to
be kept clean in a confined space and any pollutants filtered out.
Food & Water. Water can be largely recycled so only relatively small stores are
needed. Food on the other hand is more difficult and a 1000 day mission to mars
would need 1830 kg of food for each astronaut[16]. Creating or growing food using
plants and maybe animals would be needed to survive longer journeys.
Energy is relatively easy to obtain near a star. Large solar panels can supply enough
electricity to run both life support and technical systems. More energy would be
needed for engines. Several companies are working on small scale nuclear fusion
reactors that could produce a lot of power with simple fuels (isotopes of hydrogen).
They would produce very little radioactivity and are relatively clean, especially
compared to Nuclear Fission.
Radiation on Earth our atmosphere protects us from radiation from the Sun, space
ships need shielding to protect astronauts.
Gravity is surprisingly important for keeping humans healthy. We are built to live
with gravity; without it our circulatory system weakens, along with our muscles and
spine. If a human spends too long in space they suffer some severe health issues on
returning to Earth’s or another planet’s gravity[17].
Other difficulties include eye damage from contrasts of light, asteroid and space
junk impacts, maintaining pressure.
Space Travel – Getting to Space.
Most sci-fi movies like Guardians of
the Galaxy make it seem very
simple and easy to get to space,
even for a monolithic ship like the
Kree Dark Aster.
In reality it takes a lot of energy just
to get away from our atmosphere.
Dark Aster [Q]
Energy to get to space.
Getting to space takes a large amount of energy. To work
against gravity alone it takes 3,300,000 joules of energy
to lift 1 kg of mass up to the height of the international
space station (355 km). Add to that the speed needed
just to stay in orbit and this would take about 10 times
the energy. At present this energy is provided by
burning vast amounts of fuel.
Gravitational potential Energy.
𝑮𝑴𝒎
𝑼=
𝒓
G = 6.672 x 10-11 N m2 kg-2
Aside from making more efficient rockets, other options being researched include
hydrogen balloons and a space elevator.
Balloon to space.
Balloons are often used to send experiments to the edge of the
stratosphere, but any higher becomes extremely difficult. Amateur
racketeers, however, are launching rockets from balloons to get to
much higher altitudes with their rockets with less fuel.
Space elevator.
The idea of an elevator to space has been discussed for years. It
would use a geostationary satellite and a high strength cable/pole.
Using counter weight systems, loads could easily be lifted into space.
Ground-Based Lasers.
A relatively new idea is laser ablation, which is firing a laser at surface
heating it up and causing a plasma plume off the surface that propels the
object forwards. New theories combine this with gas-blasting nozzles to
reduce fuel use and increase speeds [18].
Space Travel – Moving in space.
Although there is no friction in space and you can
keep moving without a force, you still need an engine
to accelerate and change direction. All propulsion
methods in space work by pushing away fuel in one
direction to push the space craft the other way (also
conserving momentum). Conventional rockets take
a lot of fuel, so what are some other ways of pushing
matter out the back of a spaceship?
Simplified idea,
∆𝒗𝒔𝒉𝒊𝒑 =
𝒎𝒇𝒖𝒆𝒍 ∆𝒗𝒇𝒖𝒆𝒍
𝒎𝒔𝒉𝒊𝒑
Force pushing
backwards on
fuel
Fuel pushing back on the
ship, pushing it forwards.
Solar sails.
A solar sail does as the name suggests it uses light from a star hitting the
sail to propel a ship forward. The main advantage is that no fuel is
required. The disadvantage is that it isn’t very fast and works best within
the solar system heading away from the Sun.
[R]
Antimater Engine.
Antimatter particles have exactly the same properties as matter except they have
an opposite charge i.e. An electron (matter) and a positron (antimatter). When a
matter particle meets its antiparticle they annihilate each other turning into
gamma photons. These photons could be used to propel a ship forward. The
advantage is the vast amount of energy for very little mass. The disadvantage is
that it is difficult to make and store large amounts of antimatter without
annihilation accidentally occurring. It is also currently very expensive to produce antimatter.
Nuclear Fusion.
Fusion is the joining of small atoms into larger ones.
This process releases energy in much larger amounts
than fission (splitting large atoms into small ones).
The main advantage is the large amounts of energy
[S]
produced for relatively small mass. The main
disadvantage is that fission is currently needed to get fusion going and this involves a
lot of radioactive material which, in an accident, could be an issue.
Ion Rockets.
Ion propulsion systems are already in use already on many
commercial satellites. They are capable of propelling ships at very
high speeds (200,000 mph) for less fuel, although the trade off is
low acceleration. An ion is an atom or molecule that is electrically
charged. The ions are essentially fired out of the engine by electrostatic forces.
[T]
Space Travel – Getting between stars.
Even in the Milano it would still take a very long time to
travel between stars (many many years). Even if we could
propel a craft to more than half the speed of light it would
still take years to reach even the closest habitable planets.
The space fairing craft of Guardians of the Galaxy must have some warp capablities. If
we have any real hope of reaching any Exo-planets we really will need to develop
warp capabilities as well.
Is faster than light possible?
Not by any conventional means of propulsion, but NASA and other physicists believe
it might be possible by bending space and time.
NASA’s Warp Engine
NASA is in the very early speculation phase of an
idea for faster than light travel. It is called an
Alcubierre drive and involves creating a space-time
warp bubble. The ‘bubble’ shifts space around the
Warp bubble [U]
bubble, moving the object through the surrounding
space. It’s a bit like walking on a travellator (moving walkway). You can only walk so
fast, but if the ground you are walking on moves as well you travel much faster.
Will it really be possible?
Sadly, not in the foreseeable future. While the idea is theoretically and
mathematically sound the practicality of making it work is impossible for us at the
moment. There are a couple of main reasons for this: firstly it requires negative
energy density (negative mass) which is
at the moment only a theoretical
possibility; secondly the drive would
also require a large volume of antimatter (~700 kg).
There are also questions about survival
inside the bubble and the effect the
bubble would have on the destination
space. [18]
NASA’s warp ship concept [V]
Thanks to Eamonn Kerins from Manchester University whose talk at the Physics and Maths teachers
conference in 2014 on the hunt for Earth-2 inspired some of the content.
References.
1 http://www.universetoday.com/102630/how-many-stars-are-there-in-the-universe/
2 http://www.rmg.co.uk/explore/astronomy-and-time/astronomy-facts/faqs/what-is-a-galaxy-how-many-stars-in-agalaxy-how-many-stars/galaxies-in-the-universe
3: On Average, Every Star Has At Least One Planet, New Analysis Shows, Rebecca Boyle, Nov 01, 2012,
http://www.popsci.com/science/article/2012-01/new-exoplanet-analysis-determines-planets-are-more-common-starsmilky-way
4: Nearly Every Star Hosts at Least One Alien Planet, Mike Wall, March 04, 2014, http://www.space.com/24894exoplanets-habitable-zone-red-dwarfs.html
5: 10 Exoplanets That Could Host Alien Life, Elizabeth Howell, April 17, 2014, http://www.space.com/18790habitable-exoplanets-catalog-photos.html
6: Discovering planets beyond, alien atmospheres.
http://hubblesite.org/hubble_discoveries/discovering_planets_beyond/alien-atmospheres
7: List of potentially habitable exoplanets http://en.wikipedia.org/wiki/List_of_potential_habitable_exoplanets
8: Transit Photometry, A Method for Finding Earths
http://www.planetary.org/explore/space-topics/exoplanets/transit-photometry.html
9: Planet Detection through Microlensing
http://www.planetary.org/explore/space-topics/exoplanets/microlensing.html
10. The Origins of Life. By Helen Fields, October 2010, Smithsonian magazine.
http://www.smithsonianmag.com/science-nature/the-origins-of-life-60437133/?no-ist
11. 7 Theories on the origin of life. By Charles Q. Choi. March 22, 2011. Live Science.
http://www.livescience.com/13363-7-theories-origin-life.html
12. How did life originae? Evolution 101 from University of California museum of Paleontology.
http://evolution.berkeley.edu/evosite/evo101/IIE2bDetailsoforigin.shtml
13. Organic Molecules in Titan's Atmosphere Are Intriguingly Skewed. October 22, 2014
https://public.nrao.edu/news/pressreleases/organic-molecules-titan
14.The Fermi Paradox
http://www.seti.org/seti-institute/project/details/fermi-paradox
15. 11 of the Weirdest Solutions to the Fermi Paradox
http://io9.com/11-of-the-weirdest-solutions-to-the-fermi-paradox-456850746
16. Sustaining life -- Where Would a Space Explorer Find Water and Oxygen? NASA
http://www.nasa.gov/audience/foreducators/stseducation/materials/Sustaining_Life.html
17. Known effects of long-term space flights on the human body – Discovery Channel.
http://www.racetomars.ca/mars/article_effects.jsp
18. Could We Use Ground-Based Lasers To Propel Rockets Into Space? – i09 George Dvorsky - 31/10/14
http://io9.com/could-we-use-ground-based-lasers-to-propel-rockets-into-1653255068
19. Alcubierre drive, Wikipedia. – 03/11/14
http://en.wikipedia.org/wiki/Alcubierre_drive#Mass.E2.80.93energy_requirement
Images
A. Planet Xanda: http://www.8cn.tv/content/guardians-galaxy-check-out-5-pieces-xandar-concept-art
B. Planet: http://www.nasa.gov/topics/universe/features/pia14093.html
C. Morag: http://comicsen8mm.com/wp-content/uploads/2014/08/GotG-Curiosidades-06.jpg
D. Andromeda Galaxy
http://en.wikipedia.org/wiki/Andromeda_Galaxy#mediaviewer/File:Andromeda_Galaxy_(with_h-alpha).jpg
E.Gliese 581, http://en.wikipedia.org/wiki/Gliese_581#mediaviewer/File:Gliese_581.jpg
F. Gliese 832c, http://en.wikipedia.org/wiki/File:Gj832c.png
G.Kepler 22, http://www.nasa.gov/mission_pages/kepler/multimedia/images/kepler-22b-diagram.html
H. Nowhere. http://billdesowitz.com/framestore-animates-rocket-for-guardians-of-the-galaxy/
I. Transit graph diagram:
http://commons.wikimedia.org/wiki/File:Transit_Method_of_Detecting_Extrasolar_Planets.jpg
J. Guardians of the Galaxy team http://www.filmdivider.com/4394/james-gunns-visual-guide-to-guardiansof-the-galaxy/
K. Europa surface.
http://www.nasa.gov/sites/default/files/styles/673xvariable_height/public/14186_europa_image_0.jpg?itok=PYl70EE4
L. Titan.
http://upload.wikimedia.org/wikipedia/commons/5/5a/Titan_multi_spectral_overlay.jpg
O. A Watcher. http://marvel.com/universe/Uatu_the_Watcher
P. Galactic Council. Frame from Guardians of the Galaxy (2013) #2.
Q. Dark Aster. http://www.filmdivider.com/4394/james-gunns-visual-guide-to-guardians-of-the-galaxy/
R. Solar Sail. http://en.wikipedia.org/wiki/Solar_sail#mediaviewer/File:IKAROS_solar_sail.jpg
S. Fusion engine
http://en.wikipedia.org/wiki/Nuclear_thermal_rocket#mediaviewer/File:Nuclear_thermal_rocket_en.svg
T. Ion engine http://en.wikipedia.org/wiki/Ion_thruster#mediaviewer/File:Ion_Engine_Test_Firing_-_GPN2000-000482.jpg
U. Alcubierre drive, bubble http://en.wikipedia.org/wiki/Alcubierre_drive#mediaviewer/File:Alcubierre.png
V. Nasa concept warp ship. http://io9.com/heres-nasas-new-design-for-a-warp-drive-ship-1588948192