The James Webb Space Telescope (Webb) is the most ambitious and complex space observatory ever built. It will launch in November 2024 and explore the cosmos in unprecedented detail and depth. But how does it compare to the Hubble Space Telescope, the iconic eye in the sky that has revolutionized our understanding of the universe for over three decades? In this article, we will look at some of the key differences and similarities between the James Webb Space Telescope vs Hubble, and why they will work together to reveal new insights into the mysteries of space and time.

Size and Shape: James Webb vs Hubble

One of the most obvious differences between the James Webb Space Telescope vs Hubble is their size and shape. Webb has a much larger mirror than Hubble, measuring 6.5 meters in diameter, compared to Hubble’s 2.4 meters. This means that Webb can collect more light and see fainter and more distant objects than Hubble. Webb’s mirror is also made of 18 hexagonal segments that can be folded and unfolded, allowing it to fit inside a rocket fairing for launch.

Webb’s mirror is coated with a thin layer of gold to enhance its reflectivity in the infrared range of the electromagnetic spectrum, which is Webb’s primary focus. Hubble, on the other hand, observes mainly in the visible and ultraviolet range, with some infrared capability. The infrared spectrum is important for studying objects that are very cold, very far away, or hidden by dust and gas, such as the first stars and galaxies, the formation of planetary systems, and the atmospheres of exoplanets.

Webb also has a large sun shield, the size of a tennis court, that protects it from the heat and light of the sun, the Earth, and the moon. The sunshield consists of five layers of thin, reflective material that keep Webb’s instruments at a very low temperature, around -233 degrees Celsius, which is essential for infrared observations. Hubble does not have a sunshield but relies on a thermal control system that uses heaters, radiators, and insulation to maintain a stable temperature.

Orbit and Location: James Webb vs Hubble

Another major difference between the James Webb Space Telescope vs Hubble is their orbit and location. Hubble orbits the Earth at an altitude of about 547 kilometers, completing one revolution every 97 minutes. This allows it to have a wide view of the sky and to communicate easily with ground stations. However, it also means that Hubble is affected by the earth’s atmosphere, which causes some distortion and blurring of the images, and by the earth’s shadow, which limits its observing time to about half of each orbit.

Webb will not orbit the Earth but will travel to a point in space called the second Lagrange point (L2), which is about 1.5 million kilometers from the Earth in the opposite direction of the sun. L2 is a special location where the gravitational forces of the Earth and the sun balance each other, allowing Webb to maintain a stable orbit around the sun while keeping the Earth and the moon behind its sun shield. This will give Webb a clear and uninterrupted view of the sky, and allow it to observe the same region for long periods. However, it will also make it harder to communicate with Webb and to service it if needed.

Instruments and Capabilities: James Webb vs Hubble

Webb and Hubble have different instruments and capabilities that suit their scientific goals and observing wavelengths. Webb has four main instruments: the Near Infrared Camera (NIRCam), the Near Infrared Spectrograph (NIRSpec), the Mid Infrared Instrument (MIRI), and the Fine Guidance Sensor/Near Infrared Imager and Slitless Spectrograph (FGS/NIRISS). These instruments will provide Webb with high-resolution imaging, spectroscopy, and coronagraphy in the near and mid-infrared range, from 0.6 to 28 micrometers. Webb will be able to detect the faintest and most distant objects in the universe, such as the first stars and galaxies that formed after the Big Bang, and to study their physical and chemical properties. Webb will also be able to examine the formation and evolution of stars, planets, and galaxies, and to search for signs of life in the atmospheres of exoplanets.

Hubble has six main instruments: the Wide Field Camera 3 (WFC3), the Advanced Camera for Surveys (ACS), the Cosmic Origins Spectrograph (COS), the Space Telescope Imaging Spectrograph (STIS), the Near Infrared Camera and Multi-Object Spectrometer (NICMOS), and the Fine Guidance Sensors (FGS). These instruments provide Hubble with high-resolution imaging, spectroscopy, and astrometry in the ultraviolet, visible, and near-infrared range, from 0.1 to 2.5 micrometers. Hubble has made groundbreaking discoveries in many fields of astronomy, such as confirming the existence of black holes, measuring the expansion rate and age of the universe, finding the most distant galaxies ever seen, and exploring the diversity and complexity of planetary systems.

Synergy and Complementarity: James Webb vs Hubble

Webb and Hubble are not competitors, but partners in the quest for knowledge. They will complement each other by observing the same or different objects in different wavelengths, providing a complete and more detailed picture of the universe. For example, Webb and Hubble can work together to study the formation and evolution of galaxies, by combining Webb’s infrared view of the early and distant galaxies with Hubble’s visible and ultraviolet view of the nearby and mature galaxies. Webb and Hubble can also collaborate to study the atmospheres of exoplanets, by using Webb’s infrared spectroscopy to detect molecules such as water, methane, and carbon dioxide, and Hubble’s ultraviolet spectroscopy to detect elements such as hydrogen, oxygen, and sodium.

Webb and Hubble will also benefit from the data and discoveries of other space and ground-based observatories, such as the Chandra X-ray Observatory, the Spitzer Space Telescope, the Transiting Exoplanet Survey Satellite (TESS), the European Extremely Large Telescope (E-ELT), and the Square Kilometre Array (SKA). Together, these observatories will cover the entire electromagnetic spectrum, from radio waves to gamma rays, and will provide a comprehensive and multi-faceted understanding of the cosmos.

Conclusion: James Webb vs Hubble Are Two Amazing Observatories That Will Enhance Our Knowledge of the Universe

The James Webb Space Telescope and the Hubble Space Telescope are two of the most powerful and sophisticated tools for exploring the universe. They have different but complementary strengths and capabilities, and they will work together to answer some of the most fundamental and intriguing questions about the origin, structure, and fate of the universe, and our place in it. Webb and Hubble are not only scientific instruments but also sources of inspiration and wonder for humanity.

Here is a table that summarizes some of the main differences and similarities between the James Webb Space Telescope vs Hubble:

I hope this article helps you understand the differences and similarities between the James Webb Space Telescope vs Hubble, and why they are both amazing observatories that will enhance our knowledge of the universe. If you want to learn more about Webb and Hubble, you can visit their official websites.

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