What do you think when you hears the word interstellar space? You probably think of the famous movie Interstellar. Now tell me what comes in your mind when you hear the word space? You probably thinks that the space is empty. Stars are so far away from each other and so most of the space is empty. But is it true?
Let me help break it down
for you. Hi, I’m Maanvinder, your host of this podcast and I’m back with the
season 2 of this podcast after two years and we are starting it with a special
episode discussing about the interstellar space. The word interstellar is made
up of two words- inter which means between and stellar means star. So
Interstellar space is a place between the stars. Another question that arises
here is where does it begin? So the correct answer based on the best available
science is that, it starts where the star’s constant flow of material and the
magnetic field stop affecting its surroundings. To put it in simple terms, for
us the interstellar space begins where the sun’s constant flow of material and
the magnetic field stop affecting its surroundings. And that place is called
heliopause. And with the word material I meant electrons, solar wind, etc. It
is the last boundary of a star up to where the star’s magnetic field, and any
flowing material stop affecting the bodies outside place. The solar wind from
our Sun creates a bubble around our solar system and this is called
heliosphere. We know about this by detecting the temperature and concentration
of solar particles. Inside this bubble, the solar particles are hot but less
concentrated compared to the place outside this bubble where particles are cold
and are largely concentrated. This is where you enter the interstellar space.
Welcome you have finally made it into the interstellar space.
So as I earlier said, the
interstellar space is not empty. The interstellar space is largely made up of
Hydrogen which accounts for 70%, next is Helium (28%) and the remaining 2% is
heavier gases, interstellar dust, and elements that are thrown out into the
space in a supernova. If you don’t know heavier elements are born inside the
stars and when the star dies, the blast out their outer shells, spewing all the
materials out into the space. And it becomes a part of the interstellar space.
If a particular region of the interstellar space has enough material for it to
accumulate, then it can give birth to new stars in the stellar nurseries called
the nebula.
The next question you might
be wondering that has anyone or anything from our world entered the
interstellar space? Well there is one. NASA’s Voyager-1 mission in 2012 made
history by becoming the first man-made object to leave heliosphere and entered
the interstellar space. This was confirmed from the detectors onboard the probe
which detected the change in the concentration and temperature of particles
that were hitting the probe. Voyager-1 was launched in the year 1977 to study
the gas giants of our solar system. It actually did not visited them but flew
past them, gathering data about the moons, their magnetic field, and most
importantly rings. This is when it was discovered that Saturn is not the only
planet with the ring system. Jupiter, Uranus and Neptune also have thin ring
system around them. Now Voyager-1 is heading towards the Oort Cloud which is
the last boundry of our solar system. It is a place where most of the long
period comets origin from. It will reach the beginning in about 300 years and
in 30,000 years it will exit our solar system completely. It will be lost in
the vastness of deep space.
So why is interstellar space important? The simple answer is without it we wouldn’t exist. Because it is a place where the stars are born in the thick region called molecular clouds- where there is so much material for it to accumulate and born as a star. Interstellar Space is also the place from where cosmic rays enter our solar system because when a star dies in a supernova explosion; it not only spews out elements but also the cosmic rays. During day and night there is a constant bombardment of these rays into the Earth’s atmosphere. When cosmic rays collides with the atoms into Earth’s atmosphere, all their energy is converted back to matter and shower down on Earth’s surface. So this was it from me for this week. Thank you for listening. See you next week!
