The Satellite Orbit 1.5 Million km Away...

Our WMAP satellite from NASA, and Planck spacecraft from ESA, helped us calculate the shape of the universe, which - based on all the data the observable universe could offer us - was found to be flat. We talked a bit about this in our last article. Here is the basics and more to it.

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

https://map.gsfc.nasa.gov/

Today, we shall see a little more on this, especially the orbits these satellites were placed in. This has a tiny little two letter name - the L2 orbit, easy to remember. But it takes us a bit more to see what it means.

When we put a satellite in the outer space for some purpose, we know - from the very definition of satellite of course - it is in an orbit. And the particular orbit we place it in, depends on the purpose it is made for.

Satellite orbits have many different types, but the one we are interested in here, is the one around the sun, called heliocentric orbit - the orbit of every planet in solar system.

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

The satellite in the L2 orbitdoesn't move arou the earth, it moves around the sun, i.e. in a heliocentric orbit.

Short story - Long time ago, there used to be a problem - it was the effect of the gravity of sun (or moon) on the satellites. This was called the "three body problem."

Of course the first two of these bodies were earth and our satellite. The third body was either sun or moon, depending where we are trying to put the satellite. The mathematician Joseph-Louis Lagrange solved it. End of our little story. Here is more info on him.

https://en.wikipedia.org/wiki/Joseph-Louis_Lagrange

He found five points for every three body system being considered. These points were called Lagrange points after him. As you can see in the image, these are named L1, L2, L3, L4 and L5. And this is where our orbit L2 comes from.

A little introduction about all these points, L1, L2 and L3 are in a straight line joining sun and earth. L4 and L5 form equilateral triangles with earth and sun.

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

https://jwst.nasa.gov/orbit.html

** A satellite in L2 orbit is always in a straight line with the sun and the earth, because it is dragged by the combined gravitational pull of both.**

As for the heading, the distance of a satellite in this orbit from earth is 1.5 million kilometers!! And such a satellite is always used for studying the space, perhaps the only thing you'll know about earth from a distance so far is how small it looks compared to the sun.

Only two satellites have travelled in this orbit yet. The first was WMAP, which helped tremendously in finding about the shape of the universe and calculating some universal constants more precisely.

And the second was Planck spacecraft, which was improved version of WMAP, and helped us gain a lot more accurate data for the same.

Thanks to these two, it's official that our world is flat... I mean the universe... And we know much more, which I shall save for later.

http://www.esa.int/Our_Activities/Space_Science/Planck

After the grand success of these two missions, the next in line is way more cool. Let's talk about the definition of next generation space telescope.

https://jwst.nasa.gov/facts.html

Cool... as in US $10 billion investment, and one that's gonna be totally worth it.

Cool... as in it is super cool, (less than 50°K). For us, this means - no more planets hiding from the hubble in shadows, and no more guesswork about planets with water. It's a freakin Infrared Telescope, plus it's the most powerful telescope in the history of earth... if we can ignore the alien conspiracies, not sure what we can hear these days, lol... The hubble still does have it's importance though.

Cool... as in if the hubble telescope can look for "toddler galaxies", this one can look way farther in time, the cute little "baby galaxies", perhaps the first galaxies that ever formed!

https://jwst.nasa.gov/comparison_about.html

And yes, finally, the name is James Webb Space Telescope (JWST), to be launched in Spring 2019. One little possible drawback of - may be no maintenance... or may be this too is a plus point, thanks to the advancement in robotics and artificial intelligence. Some information on James Webb is here.

https://jwst.nasa.gov/whois.html

First image was taken from pexels.com while the other is taken from the nasa.gov website.

Check these links out if you want. There's way more cool stuff out there... Did you know JWST has gold plated mirrors...and this gold weighs more than a golf ball!! Plus these mirrors are bigger than any other infrared telescope ever built... the list just doesn't end... May be I should save it for the next post.

See you soon, take care.