Science fiction has come up with countless
ideas for weird forms of life not based on boring old DNA, or even on matter as we know
it. There’s Stanislaw Lem’s sentient ocean
in Solaris, or the neutron star civilization made of nuclear matter in Robert L Forward’s
Dragon’s Egg. Oh, and here’s an extra crazy one - life composed
of cosmic strings and magnetic monopoles, evolving in the hearts of stars. Oh, wait a minute - that last one is an actual
scientific proposal. Scientists can sometimes be a little carbon-chauvanistic
when we imagine other possible life forms. Which is understandable - carbon-based chemistry
enables the most complex structures that we know of in this universe. But could some other mechanism exist that
could allow the incredible chemical diversity needed to power life? Well, not that we know of. But that hasn’t stopped some scientists
from looking. One of the most bizarre proposals for life
not as we know it doesn’t even use atoms. It proposes that fundamental kinks and defects
in the fabric of the universe - cosmic strings beaded with magnetic monopoles - may evolve
into complex structures, and even life, within stars. This idea was just published in Letters High
Energy Physics Letters by physicists Luis Anchordoqui and Eugene Chudnovsky, and today
on Space Time Journal Club we’re going to see how legit this idea actually is. But first we need to go through some of the
basics. What exactly are cosmic strings and magnetic
monopoles? Both of these are fascinating subjects well
overdue for their own episodes, so I’ll keep in brief here. Cosmic strings and magnetic monopoles are
what we call topological defects. The best way to describe topological defects
is with some examples. Imagine a fur rug in which you can brush the
fur to lie in whatever direction you like. If the fur is pushed to the left at one end
and the right at the other end, then somewhere in between there must be a transition between
the two states. There’s no way for that transition to be
smooth, so you have this line. You can move the line around by brushing the
rug left or right, but you can’t get rid of it without brushing the entire rug in one
direction. You could also get a topological defect if
you tried to brush the rug into a spiral. The transition between all points would be
smooth, with the grain changing angle only slightly. But at the eye of the spiral you’d have
a non-smooth transition. And that’s the common feature of a topological
defect - a sudden change in the “grain” of some space that can’t easily be disentangled. You can have exactly the same thing in magnetic
materials, where the direction of the poles of the little magnetic particles changes across
the substance. Topological defects are also found in crystals. They form during the phase transition from
liquid to solid. That crystallization can begin in different
places in the liquid. And these lattice regions spread and join
until you have a single crystal, but if those initial regions didn’t all line up in the
same way then you have defects where the regions meet each other. Quantum fields should also be able to develop topological defects. These may have been formed soon after the
Big Bang when massive phase transitions swept across the universe. These transitions were analogous to the phase
transitions between states of matter - for example, water freezing into ice. But here, the quantum fields themselves changed state due to the rapidly dropping temperature. The technical term is “spontaneous symmetry
breaking” - the same events that led to the appearance of the separate forces from
an initial unified force. We’ll be discussing that more in the future,
but for now the important thing is that these phase transitions could have resulted in different
types of topological defects, just like when crystals form. Let’s go through the possibilities: a 0-dimensional
topological defect is a magnetic monopole - like the north or south pole of a bar magnet
that somehow lost its counterpart. A 1-D topological defect is a cosmic string
- an extremely thin filament. 2-D defects are called domain walls - they’re
the boundaries between regions of the universe with different properties - for example, different
vacuum energies. We’re interested in the strings and monopoles
for now. In certain theoretical scenarios, a monopole
can be connected to the end of a string - or two strings, actually. Such monopoles are called beads. And you can have a chain of beads - a necklace.. Anchordoqui and Chudnovsky imagine a type
of nuclear life, in which these chains form complex structures that can have a sort of
chemistry - possibly even evolving into what we might call life. The goal of their study was to figure out
under what circumstances this might happen. The authors lay out three conditions for life
that they investigate. Let’s go through them. Condition 1) The ability to encode information. Fair enough - our DNA encodes all the instructions
our cells need to build the molecular machinery of life. It’s hard to imagine a life form that didn’t
have a way to store information. Condition 2) The ability of information carriers
to replicate faster than they disintegrate. Again, straight forward - any given chain
of molecules holds information, but it isn’t much good if it falls apart before it reproduces
itself. And 3) a source of free energy. This is something we know is essential for
any life, including nuclear life. Let’s go through each of these conditions in detail. Can these string-monopole necklaces store
information? Well, in DNA there are 4 different base pairs
and the ordering of those base pairs is a language - it dictates the order of amino
acids transcribed into proteins. With simple magnetic monopoles, the only possible
necklace is an alternating series of north and south poles - or poles and anti-poles. There’s only one possible configuration,
and so there’s no way to store information that way. But if you add slightly more exotic physics
you can form different types of monopole. For example, there’s this scenario in this
early universe symmetry-breaking stuff where, after the monopoles form, they split in two
- into so-called semi-poles. There are four types of seminole - two for
each of the original monopole type. Four coding “letters” - sounds a bit like
DNA. Semipoles have an added bonus: whereas monopoles
and anti-monopoles will always attract each other and annihilate if they come together. With semipoles, it’s possible to form string
segments capped by NON-annihilating semipole pairs that actually repel each other. In this way, it may be possible to develop
complex string structures, analogous to chemistry. And maybe you can even build something like DNA. OK, moving on to life condition number 2:
can these information carriers replicate faster than they can disintegrate? These necklaces are probably not too stable
- but that’s OK as long you can replicate them faster than they fall apart. And this is where stars come in. Others have speculated that cosmic strings
may get trapped inside stars in the process of star formation. Those stellar interiors might then provide
the mechanism for necklaces to rapidly change and even replicate. Depending on the stellar type and region,
the insides of stars can be very turbulent places. Flowing plasma and magnetic fields may stretch
and break necklaces, which could reconfigure them over and over until they find a state
that is stable in the environment, combined with developing the ability to replicate faster
than they are torn apart. As for how that replication happens - well
the study doesn’t go into detail, except to say that it might be catalyzed by interactions
with atomic nuclei in the star. Perhaps nuclei somehow help necklaces build
a parallel chain of beads, that then peels off as an identical necklace, similar to how
RNA reproduces. And finally, life condition number 3: do we
have a source of free energy? By free energy, I don’t mean energy that
you don’t have to pay for. I mean energy that is available for use, in
a thermodynamic sense. Energy can only be used to do work if there
exists differences in the amount of energy in different possible states. If energy is concentrated in certain places
we would call that an ordered, low entropy situation. Energy likes to spread itself out as evenly
as possible, moving towards disordered, high-entropy states. It’s possible to use energy as it flows
between different states in this process, like putting a water wheel in a flowing river. For example, life uses the energy flowing
from the high energy-density of the Sun to the lower energy density of the Earth. In fact we talked about all of that in our
episode on the physics of life. We saw that these temporary increases in order, represented by life, actually speed up the process of smoothing out all of the energy. Little low-entropy blips like life ultimately
accelerate the increase in entropy of the universe. OK, so inside a star there’s definitely
free energy. Energy flows from the fusion engine in the
core to the surface. It’s conceivable that a lifeform could harness
that flow. Well what would that look like? Well, it would have to hasten the spreading
out of energy. Energy could be spread more evenly across
the electromagnetic spectrum, which would look like cooling - the star might appear
cooler than it should. Or perhaps the nuclear reactions in the core
proceed faster, hastening the dissipation of the star’s energy through space. At any rate, the star should behave differently
to what our stellar physics models predict. There are a few stars in our modern surveys
that don’t quite act as they should, however there are many other possible explanations
and it might be a little premature to claim discovery of a new lifeform. We’re going to have to get a much better
understanding of cosmic strings and monopoles - and, you know, actually verify that they
exist in the first place - before we can decide whether they can interact with the complexity
needed to evolve into life. And the authors of this paper are not pretending
that any of this is likely - their point is more to show that other possible bases for
life might exist, beyond the familiar carbon chemistry. So are the stars filled with thriving ecosystems
of critters built from fractured quantum fields? Not likely, but not yet impossible. And who knows what other bizarre life forms
may be waiting to be discovered, in distant, stranger parts of space time. Hey Everyone. A few announcements before we get to comments It's that time of year again where PBS DIgital Studios and Space Time want to hear from you Every year we do an audience survey that helps us know what you like, what you don't and want other kinds of content you want to see. The Space Time audience has always done a great job making their voices heard on the survey, so check out the link in the description and let us know what you think! Well regardless going to keep making Space Time and keep making it better - and a big part of what makes that possible is the support we get from some of you on Patreon. Those few bucks a month really lets us plan much further ahead. For those of you who might be thinking of helping out - added bonus is that we have this hoppin Patreon discord channel where space and physics geeks from around the world ponder the nature of reality. And while I'm talking Patreon, I have to give a gigantic shoutout to James Younger, who supports us at the Big Bang level. For those who don't know, James is a higher being composed of cosmic strings and monopoles, visiting Earth from the core of the Sun to help spread cosmic wisdom. By, like, supporting physics youtube shows and such. Thanks James, may your semipoles never annihilate. Hey everyone. Comment responses today are on our episode on the pursuit of beauty in physics. A very contentious topic these days - and
so sparked some passionate debate in the comments. I’m not going to go too deep into the back
and forth right now… but will make my own stance very clear. Many of you mentioned Sabine Hossenfelder,
whose book Lost in the Math was a big part of highlighting this issue of excessive dependence
on beauty. She’s of course not the only one to highlight
this. But tor Sabine’s own words read the book and
check out our Theories of Everything livestream from a month ago, also with Lee Smolin and
Eric Weinstein. Look, I don’t want to get to much into where
I agree or disagree with these guys here - but I will say this - it’s useful to highlight
when we think science is going astray, and Sabine and others see a real problem with
the excessive weight placed on the importance of mathematical beauty, by some, perhaps by
many, in the theory-of-everything game. But I also have to add - do not throw the
baby out with the bathwater. Arguably the greatest advances of the 20th
century were in part driven by the simple intuitions of the likes of Einstein and Dirac
that physical law should be mathematically elegant. So we should try to learn from the past successes
of this pursuit of beauty in math, as well as its failures. The failures tell us that the narrow-minded
pursuit of pure beauty at the expense of everything else is doomed. Why? Because beauty is not a fundamental property
of the universe - it is, by definition, a subjective sense. Which means it’s a proxy for other more
fundamental qualities. So let’s identify those qualities that our
beauty-compass is pointing to. We can allow our powerful and inexplicable
intuition for beauty guide us subtly, while at the same time remaining healthily skeptical
even of our own intuitions. Regarding the epicycles in Ptolemy’s theory,
Ry706 says “adding epicycles upon epicycles can represent any motion is literally true
by Fourier theory”. Ry706 - that’s exactly what epicycles are,
thank you! For those unfamiliar - Fourier’s theorem
tells us that we can represent any continuous, periodic function can be represented as a
sum of sine waves of different frequencies. But then motion in a circle can be represented
by 2 separate sine waves for displacement in the x-y directions. So any arbitrarily complex orbital motion
can be represented with enough sine wave pairs in a fourier series - which can also look
like a series of epicycles. That’s why Ptolemy was able to make this
Earth-centered model sort of work - with enough epicycles he could have created a working
model centered on the moon, or on the library of Alexandria, or on his mom. And this is why Occam’s razor is useful
- it kindly requests that we please slice off as many literal and metaphorical epicycles
as possible. Speaking of beauty, Joey Crowly asks everyone
to please give some mad props to the animators of this show, with the production quality
being absolutely off the chain. Uh, you’re not kidding Jaoey. Animators Leo, Yago & Pedro and team are the
ones who really bring this show alive. I felt terrible asking for the fur rug animation
from today’s episode - and honestly I don’t know how they managed to do pull it off in
a couple of days. Leo and team - mad props from all of of us
fans. Shirsendu Chatterjee points out that it’s
finally time to give the address to the time traveler’s party that we hosted a year ago. At the time no one showed up, but that only
tells us that time travel is false if we actually give the address as promised. Done - here’s the time and address. We wrote it in neutrinos, just to make sure
only sufficiently advanced civilizations can read it - don’t want any of those lame steampunk
time travelers showing up. See you at the party. Which we didn’t. I guess that scientifically proves that time
travel is impossible, or that we’re scientifically conclusively unpopular with the cool time traveler
set. Cue highschool flashbacks.
the formation of life requires a fairly dense supply of whatever that life is going to be made out of. is it credible that there would be enough cosmic strings and magnetic monopoles in a star for abiogenesis.
also can more be made.
Pretty far fetched
Matt is waiting to have all the facts before releasing a pure speculation video on Venus. I respect that.
for all we know the sun might be conscious the earth might be alive, the possibilities are endless
Short answer: no.