TEAM WORLDWONDERINGS:-These are truly mesmerising, unprecedented photos, which tell us interesting things about the universe. One of these photos gives us the oldest glimpse of the universe. We can see 13.1 billion years into the past.In another, we discovered an alien exoplanet where water, or H2O, has been found. Come, let’s try to understand these new discoveries, in today’s videos. “The James Webb Space Telescope is the largest and most powerful space science telescope ever built.” “Every image is a new discovery.
And each will give humanity a view of the universe that we’ve never seen before.” “So the Webb is able to look at the formation of the first stars and the first galaxies. The Webb is tremendously exciting.” “Light from other worlds, orbiting stars, far beyond our own. It’s astounding me in many ways.Friends, this telescope cost about $10 billion. It took NASA 25 years to work out its design and development. And most interestingly, the spot where this telescope is located currently, it is operating at the temperature of -266.75°C.
Absolute zero temperature of -273°C, temperature
It is only a few degrees warmer than that. To maintain this temperature, the James Webb Space Telescope doesn’t orbit around Earth, like the Hubble Space Telescope. Rather, it orbits around the Sun. About 1.5 million km from Earth, there’s a point known as the L2 Point, there’s it is always in the Earth’s shadow, in a way that it can safely orbit the Sun.As you can see in this video. To block out the rest of sunlight, a sun shield has been attached behind it. It’s nearly as big as a tennis court. Do you know what is the focal length of this telescope? Those of you who use DSLR cameras as a hobby would know the lens of those cameras usually has the focal length somewhere around 24mm, 35mm or 50mm.
The focal length of the James Webb Space Telescope is more than 2,500 times of it. 131.4 meters. Meters, not mm. It’s main mirror weighs around 705 kg. I have discussed these technical aspects in the previous video on James Webb Space Telescope I will put a link to it in the description below. If you want to know how this telescope was built, and how it works.Let’s get straight to the point, and talk about the photos taken by this telescope. Before this, let me remind you that this is our electromagnetic spectrum, Different EM waves have different wavelengths.
Spectrum of visible light
The light which we can see with our naked eyes. The rainbow colours.Violet, Indigo, Blue, Green, Yellow, Orange, and Red. This wavelength ranges from 0.38 to 0.7 micrometer. Wavelengths higher than red, are known as infrared. And the wavelength on which this James Webb Space Telescope can take pictures in ranges from 0.6 to 28 micrometers. There is a small overlap with the visible light, but mainly, this telescope works with the infrared portion.
As I told you about its advantage in the previous video, you can look through the gases and clouds, because of the larger wavelength of the infrared light. The longer the wavelength, the easier it is to go through objects.such as radio waves, whose wavelength is measured in kilometres. We can listen to them through the radio, those waves can travel through our homes and walls.2 infrared cameras are mounted on this telescope. The Near Infrared Camera, NIRCAM, to capture the shorter infrared wavelengths. And the Mid Infrared Instrument, MIRI Cam, to capture the longer infrared wavelengths.
Galaxy cluster, SMACS 0723
The galaxies closer to our camera, have a high gravitational force such that they are distorting the light coming behind them.It creates a magnifying glass of sorts. This phenomena has been named Gravitational Lensing. With its help, we can see objects behind it. It isn’t a photo which was simply clicked by the telescope as is. Similar to how you point your camera, tap a button and take the picture, it’s not so. It took 12.5 hours to take this photo.
Actually, the telescope had to take several different images, at different wavelengths, and later combined them. And we’re now seeing this combined photo.
In it, the galaxies that appear redder in colour, are farther from us. The redder the galaxy, the farther it is. While we’re discussing the distance, look at the next photo.This has been named Stephan’s Quintet. It is a cluster of five galaxies, the prefix ‘quin’ is used for the number 5, such as ‘quad’ is used for 4, This quintet is more of a Quadtet. Because the leftmost galaxy among them, are 40 million light years away from us, and the other 4 galaxies, are about 290 million light years away.As you can see, the photo of the leftmost galaxy looks more HD, if you zoom into this photo. While the other 4 galaxies look quite blur.
This from NIRCAM and MIRI Cam both
Friends, now let’s come to our most interesting photo. It is not even a photo. But this has piqued the curiosity of scientists the most. It is a spectographic data of the planet WASP – 96B.It is an exoplanet 1,150 light years away from us. Exoplanet is a planet that lies outside our solar system. Apart from the two cameras, the James Webb Telescope is equipped with a NIRISS. NIRISS stands for Near Infra-Red Imager and Slitless Spectograph. Spectograph is an instrument which measures the intensity of the various wavelenghts of light.For 6.5 hours, the NIRISS measured the light coming from this planet. The result of the measurement was this light curve.
The data plotted on this graph, tells us that there’s water on this planet, H2O. Additionally, there’s some haze and clouds as well. You might wonder how can we determine whether a planet has water or not simply by measuring light? Even though we haven’t even seen its photo.The answer to it is very simple, friends. As I told you at the beginning of the video, each colour has a distinct wavelength of light. And the colourful world that we see around us, it’s all an illusion created by the wavelength. For example, why do we see trees, plants, and leaves as green in colour? Because they contain chlorophyll.