astronomy is very very visual because it's so accessible you know anyone can look up and see the
stars but it also brings excitement i think to the general populace and that's really important for
astronomy but i think for science in general it excites people and and they want to know more
so fast radio bursts are are one of these objects where we look out there and something
happens that we've never seen before and then we have to explain them and fast radio bursts are
are a perfect example of this where bursts of radio transmission that is photons in the radial
part of the electromagnetic spectrum were observed from different areas on the sky the problem was
that they occurred once and so when you have one event and you might not necessarily know exactly
where it is you can't follow up to see what's there so we have these mysterious fast radio
bursts appearing all over the the sky in essence and again in the like in the in the radio part of
the electromagnetic spectrum well several of them over the past several years have repeated and so
because they've repeated it that has allowed us to go back to localize where they are on the sky
and therefore where they are in space follow up with other sorts of telescopes and instruments to
study them more more thoroughly fast radio bursts appear to be neutron stars in the extreme side
that are restructuring and all sorts of star quakes are occurring and there's a tremendous
release of energy and some of that comes out in the radial part of the electromagnetic spectrum
that we see as a burst that happens very rapidly and so hence the name fast radio burst
a neutron star is the end product of a very violent event that is the collapse and explosion
of a star that's more massive than the sun in what we call a supernova event and supernova
exploding stars exploding massive stars can leave behind black holes
and they can leave behind these so-called neutron stars which are very dense they're not quite black
holes but they're very dense material they're the former core of the of the exploding star
that has collapsed down to some tens of kilometers in diameter the size of a of a medium-sized city
and so because of that they are very very dense uh some of them all of them probably are
rotating very rapidly at least when they form some of them have magnetic fields that attract
material in the area charged particles and squirt them out as jets and if we
happen to see those jets pass our line of sight we call those objects a pulsar
and some of those neutron stars have extremely high magnetic fields we call them magnetars
so magnetars appear to be the extreme uh extremely magnetized end of
the neutron star spectrum so there are neutron stars that for whatever reason have extremely
strong magnetic fields much stronger than the magnetic fields that of the earth's magnetic field
the strongest magnets that we can produce on earth which are much stronger than earth's magnetic
field stronger than the sun's magnetic field by hundreds of thousands if not millions of times
and so these compact objects are very extreme they have these very very intense magnetic fields and
because of that they're doing intense and exciting things now you know you might ask why do we care
and okay so they're an astronomical object that we want to learn more about
but they're a an extreme region of space that has magnetic fields in this case that are much
stronger than we can produce on earth and so we can use that as a laboratory and learn
about magnetic fields and learn about material and magnetic fields and so there's a non-astronomical
interest in these objects as well and that is as a cosmic laboratory
so the black widow uh binary star first of all let's let's look at what binary stars are
and stars form out of collapsing gas clouds they turn on and they start
fusing and shine and produce heat and light and energy just like our sun our sun is
isolated in space it has no stellar companion that's that's gravitationally bound to it lots
of planets of course but there's not a stellar companion and on the contrary most stars
are formed with another companion if there's another one so there's two stars we call that
a binary star system where they are locked gravitationally and they orbit each other
other stars have multiple star companions and so that's the more common way that stars are formed
in the universe so in a binary star system usually the stars are have the same mass
mass is important for the subsequent life cycle of a star the more massive
star is the faster they consume their their fuel and and and and their life times so
if we have a binary system where there's a mismatch in mass one star may become explode
as a supernova and leave the other lower mass star behind because it's not quite at that point in its
lifetime and so the end state of super supernova could be a neutron star and a neutron star
can produce winds of charged particles blowing off charged particles that are nearby if the two
stars are very close to each other that wind of charged particles can interact with the so-called
non-evolved companion star and remove its outer atmosphere and so this is the phenomenon that we
call the black widow binary star system it's rare because you know binary stars can be in multiple
configurations they can be very close they can be further apart and the further they are apart
the wind is still coming off of the evolved companion the neutron star
in this case but it's far enough away that it's not damaging the the nearby companion if they're
too close then that wind can again can ablate can remove the outer atmosphere of the companion star
so dark matter we don't know what dark matter is so that's an excellent question it's one that i
can't answer at the moment dark matter is dark because it doesn't interact electromagnetically
with anything else so how do we know that it's there i mean if we can't see it with telescopes
how do we know it's there well we know it's there because it while it doesn't interact or
very weakly interacts with electromagnetic radiation it interacts gravitationally
so it has a mass and any mass has gravity and so we know that dark matter is there because we can
detect its presence through how it's affecting other objects through its grav through gravity
so it's there we can see it gravitationally but we can't see it electromagnetically
so at the moment we don't yet because of that we don't yet know what it is there are a number of
hypotheses for what it is uh subatomic particles the so-called weakly interacting massive particle
or wimp is is a key uh possibility at the moment we would expect to find these
dark matter particles in our in our particle accelerators on earth uh it's a very difficult
observation to make because they're very weakly interacting apart from gravity and yet we have not
not yet discovered them in the particle accelerators so it's looking like the wimp
might not be the dark matter particle and then that opens the question for what is it and we
still don't know so very very important it's very important because it's a it's a gravitating mass
it's even more important because some 95 percent of the mass of the universe is in this state
that we call dark matter so 90 95 of the material that's that's gravitating and is out there
is some something that's completely unknown and that's a bit disturbing uh for an astronomer but
you know i have no doubt that we we will determine what it is eventually if it's a subatomic particle
it we would need particle accelerators such as the large hadron collider and and uh others
but if it's very weakly interacting we need those detectors to be better than they are now
and so if we're not detecting it now it's either because it doesn't exist or we don't have the
capability to detect it so you know we must wait for next generation of of particle accelerator
detectors now there are particle accelerators in the universe jets of charged particles coming from
near black holes and and whatnot and those cosmic laboratories can can produce higher energies that
we than we can ever hope for on earth and so maybe from those sorts of accelerators if we observe
the jets from uh the centers of galaxies for example we might be able to detect dark matter
uh candidates so it's just more observations of these natural laboratories and the laboratories
on earth and we continue theoretically trying to determine if there are other candidates as well