This is an update in my continuing coverage of the intriguing star system called TRAPPIST
- 1 that includes no less than seven earth-like rocky planets, see my first video update on
that on this channel for the back story.
In the few days since NASA's press conference, a clearer picture is emerging on just how
bizarre yet familiar this star system is.
There seems to be a high likelihood for liquid water existing on two of these worlds, and
in fact could exist on all seven if the atmospheric conditions of some of those worlds allow it.
But there is actually a very specific reason why scientists think this is likely.
When planets form out of the discs of debris that often surround young stars, the materials
in the disc are not uniformly distributed.
You can infer just where a planet originally formed by its composition.
In early solar systems planets tend to migrate until they ultimately settle into stable orbits.
The current models for TRAPPIST - 1 indicate that the planets of the system formed relatively
far out from the star and eventually migrated inward.
This would mean that they formed in an area of the disc that was rich in water ice.
Warm water ice up, and you have liquid water.
Where you have liquid water, you have the potential for life.
Now one point against TRAPPIST - 1's planets developing life is their proximity to the
star.
They are really close and when you're close to a star you are subject to some serious
radiation.
One type of radiation that's unfriendly towards life is ultra-violet.
Here on earth we are protected from the sun's UV radiation by the ozone layer.
A similar such ozone layer may protect one or more of the worlds at TRAPPIST - 1, only
further study will tell.
Another issue is the presence of a strong magnetic field to deflect radiation.
These planets would need that to support life, but as with Earth, it has a strong magnetic
field so they may too.
Again, further study here is needed.
But in one area the new planets are favored for life.
Life here is linked to tidal pools early in earth's history where the magic of organic
chemistry could be worked that eventually leads to life.
For life to develop, at least according to current thinking, you need tidal pools.
Tidal pools need tides.
Tides require a moon.
Now, at first glance the mechanics of the TRAPPIST planetary system seems to disfavor
moons.
These planets pass very close to each other and affect each other with their gravity and
probably would have tossed any moons out of that area pretty quickly.
But that's also the saving grace.
They pass so close that the planets themselves would create tidal effects on any water present
in the system.
So here we have a case where the circumstances allow for tides without moons.
So let's say, hypothetically, that on one of the planets microbial life has developed.
The interesting thing here is that if it has, then at some point it is likely that life
will arise on any of the other planets in the system that allow for it.
The reason for this is panspermia.
This is a process where impacts by asteroids can blow debris off of one world where it
would then wander space for a bit and land on another.
It is possible for dormant microbial life to survive the journey and in fact it's possible
that we've seen this first hand, though the subject is more hotly debated than is commonly
known.
During the Apollo 12 mission to the moon astronauts retrieved the main camera from the surveyor
3 mission that had been sitting on the moon for three years.
When they got it back to earth, they found living bacteria between the lenses that appear
to have survived the harsh conditions of the moon.
Now, this has been widely criticized because there was apparently plenty of opportunity
for contamination but it still seems rather odd that the handful of bacteria all happened
to be the same species and when cultured behaved as though they had been dormant.
The truth will likely never be known since the cameras are not now in a sterile environment.
This sort of thing could easily occur with rocks, and might in fact have happened in
our own solar system.
One existing theory is that life in our solar system actually originated on Mars and was
deposited on this planet by a meteorite.
This theory is attractive because at the time that life arose on earth, the environment
here was not that great for the formation of life.
Mars had once been a more hospitable place for life than Earth in this solar system.
Given the very close proximity of the planets of TRAPPIST - 1, these planets would pass
by each other and look even larger in the sky than our moon does, it seems likely that
materials get exchanged, or did in the past, due to impacts.
As a result, life may have hitched a ride and populated more than just one world in
this system.
Only time will tell if these worlds at TRAPPIST - 1 hold the potential for life or are more
likely to be sterile worlds.
After all, three planets also lie within our sun's zone of habitability and any alien culture
out there studying us probably initially wondered if life could exist on all three.
But as they study the atmospheres of our planets, they would quickly see that the closest of
the three, Venus, is unsuitable for most straightforward kinds of life and they would see that Mars
is too small to hold the necessary atmosphere for much other than underground microbes.
But then they would see our blue jewel and the oxygen life creates in its atmosphere
and then they would know.
Thanks for listening!
I am futurist and science fiction author John Michael Godier currently on the cusp of releasing
a new book.
It's called Supermind and explores the implications of the universe being a computer simulation
set amongst a love story gone horribly wrong and be sure to check out my other books at
your favorite online book retailer and subscribe to my channel for regular, in-depth explorations
into the interesting, weird and unknown aspects of this amazing universe in which we live.