The Magellanic Clouds

NITK during the monsoons has its own picturesque beauty. You may have noticed the pink shade of clouds contrasting the pale blue sky. It’s really something, isn’t it! But alas it’s just some passing clouds. The Magellanic Clouds are no different. Although we have seen them for thousands of years, scientists have now figured out they are indeed passing clouds.

Wait!! We have seen them for thousands of years? I have never heard of Magellanic Clouds, let alone SEEN them. Relax. You are not alone. The entire northern hemisphere is with you on this. You see, the Magellanic Clouds can be seen only from the southern hemisphere. So unless you were on a desert safari in the remote deserts of Australia or trekking in the mountains of Peru, I highly doubt you have seen them with your naked eye!

The large Magellanic cloud (LMC) and the small Magellanic cloud (SMC), named after Ferdinand Magellan the traveller, are basically small irregular galaxies found in the Local Group*. These Clouds are one of the nearest celestial bodies to our Milky Way galaxy being 160,000 light years (LMC) and 200,000 light years (SMC) away in contrast to the Andromeda galaxy which is about 2.6 million light years away. The LMC and SMC weigh about 10 and 6.5 solar masses each.

 

4
The Small Magellanic Cloud
2
The Large Magellanic Cloud

These clouds are quite different from our galaxy. First being they are in have an irregular shape, unlike our spiral galaxy. They have an unusually high amount of dark matter halos** and have a completely different matter composition compared to that of the Milky Way.

So obviously something so big, heavy, and close to us must be bound to us by gravity right? And since these clouds were there for us since the dawn of mankind we consider them our neighbours! It is believed that they might merge with the Milky Way galaxy in about 4 billion years.

However, a recent study by a Harvard-Smithsonian Centre for Astrophysics and Space Telescope Science Institute research team suggest otherwise. By combining proper motions and radial velocities, this team found that the LMC speeds through space at 378 km/sec while the SMC has a speed of 302 km/sec. (Imagine the speeding ticket!). Due to their very high velocities, it is quite a possibility that the Magellanic Clouds are just passing clouds and would leave us in the future.

Just like all things in life come and go the Magellanic Clouds are no different. They are known as the ‘traveller galaxy’. However, their presence and impact in our little world, have thought us much about astronomy, space and even a tiny bit about our puny existence in this universe.

*Local group is a group of more than 54 nearby galaxies

**A dark matter halo is a hypothetical component of a galaxy that envelops the galactic disc and extends well beyond the edge of the visible galaxy. The halo’s mass dominates the total mass.

Vasista Ayyagari
3rd year, Mechanical Engineering
NITK

 

Sources:

Space Facts

http://www.spitzer.caltech.edu/images/2875-ssc2010-02a1-Little-Galaxy-Explored

https://phys.org/news/2007-01-magellanic-clouds.html

https://en.wikipedia.org/wiki/Magellanic_Clouds

 

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