This episode of Primal Space is supported
by Audible, get 3 months for half price by visiting Audible.com/primalspace or text “primal
space” to 500-500. When the Hubble Telescope launched in 1989,
it promised to expand our understanding of the universe with every picture it took. After 30 years of service, it did exactly
that. From observing distant stars and galaxies,
to measuring the exact age of our universe, Hubble answered so many questions. Now it’s time to answer the next set of
questions as we continue to uncover the mysteries of our universe. In this video, we’re going to look at the
James Webb Space Telescope. We’re also going to look at what it will
observe and how it could find the most Earth-like planets, with the highest chance of supporting life. After 30 years and millions of pictures later,
the Hubble Telescope has peaked in terms of how far back into the universe it can observe. Hubble’s furthest observation was made in 2016, when it captured an image of Galaxy GNZ11. This Galaxy is 32 billion light-years away
but due to the expansion of space, the light we see from it shows the Galaxy as it was
13.4 billion years ago. Although this is just 400 million years after
the Big Bang, Hubble is unable to see anything further than this since it’s limited by
the range of wavelengths it can observe. As the light from distant galaxies travels
from one point to another, its wavelength is stretched by the constant expansion of
space. By the time the light reaches Hubble, it’s
stretched to a wavelength outside of Hubble’s viewing range. Anything that’s stretched to a wavelength
above near infrared is unobservable by Hubble. In order to observe the most distant and earliest
objects in our universe, we need to observe the infrared light that comes from them. This is where the James Webb Telescope comes
in. When development began in 1996, many of the
technologies needed for the telescope had yet to be invented. An enormous sunshield is required to keep
the telescope at an extremely low temperature. Special wavelength sensors that can operate
at cryogenic temperatures also had to be developed for this telescope. James Webb will observe primarily in the infrared
range, which will allow it to see things that Hubble couldn’t see. When stars and planets are first forming,
they’re often hidden behind enormous clouds of dust which absorb visible light. Hubble is able to observe these magnificent clouds but it can’t see what’s going on behind them. This is the famous Pillars of Creation Nebula
which Hubble imaged in 2014. Observing it in infrared light reveals just
how much is going on behind these dusty clouds. But James Webb won’t be the first infrared
space telescope. Over the years, there have been several infrared
telescopes in space, but none of them have had the detail and capability that James Webb
will have. The resolution of a telescope is limited by
the number of wavelengths it can fit across its mirror. A larger mirror allows for a higher resolution. The Spitzer Infrared Telescope has a mirror
just 0.85m in diameter. Hubble’s mirror is slightly larger at 2.4m,
but James Webb will have an enormous mirror, measuring 6.5m wide. This will give the telescope an incredibly
precise resolution, capable of observing a penny from 40km away. This level of precision will be required if
it wants to discover the most distant galaxies and planets in our universe. One of the most impressive goals of the James
Webb Telescope is to find and analyze the most distant Earth-like planets in our universe. To do this, James Webb will focus on a single star which is known to have planets orbiting it. As a planet crosses in front of the star,
the telescope will measure a small dip in light. At first, this will help to determine the
size of the planet, but measuring dips in multiple wavelengths will give us even more
information. Since atoms and molecules absorb light at
different wavelengths, measuring dips at specific wavelengths will signify which molecules are
present in the planet’s atmosphere. If the telescope measures a dip in light at
around 1.15 and 1.4 micrometres, we can tell that the planet’s atmosphere contains water
vapour, since H2O absorbs a larger amount of light at those wavelengths. James Webb will be able to observe a large
range of wavelengths from visible light through to mid infrared. This will be perfect for detecting various
kinds of molecules that are common on Earth like: CO2, Oxygen and Nitrogen. Along with Webb’s incredible sensitivity,
it will be able to discover extremely distant planets that bear an uncanny resemblance to
our own. Finding these Earth-like planets will teach
us more about our own planet while taking us one step closer to proving that we are
not alone in this vast cosmic arena. So as we patiently wait for the James Webb
Telescope to be launched, we can look forward to the incredible scientific discoveries it
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or text Primal Space to 500 500. Thank you very much for watching and I'll see you in the next video!
