Sunday 16 October 2022

Space Highlights Of The Month Of August - Rishona Chopra

The new image from the Hubble Space Telescope captures a galaxy named SGAS J143845+145407, located in the northern Boötes, one of the most prominent constellations in the sky. The mirror image of the galaxy at the centre of this new photo results from strong gravitational lensing. This astronomical phenomenon can warp, magnify or even duplicate the appearance of distant galaxies"Gravitational lensing occurs when a massive celestial body — such as a galaxy cluster — causes a sufficient curvature of spacetime for the path of light around it to be visibly bent, as if by a lens," according to a statement from the European Space Agency (ESA). "Appropriately, the body causing the light to curve is called a gravitational lens, and the distorted background object is referred to as being 'lensed.'"

At the centre of the new Hubble image, the bright light emanating from SGAS appears as an arc or ring around either side of the object that lies between the distant galaxy and the space telescope. The image also captures several other galaxies and celestial objects scattered across space. Gravitational lensing also allows astronomers to observe objects that would otherwise be too far away or too faint to be seen. The distortion caused by the foreground object acts as a natural magnifying glass, zooming in on more distant celestial objects. The recent image of galaxy SGASJ143845+145407 was taken as part of a larger Hubble initiative to study galaxies of the early universe using gravitational lensing to examine the galaxies up close." The lensing reveals details of distant galaxies that would otherwise be unobtainable, allowing astronomers to determine star formation in early galaxies," ESA officials said. "This, in turn, gives scientists a better insight into how the overall evolution of galaxies has unfolded."

At the beginning of the month, JWST captured images of the Cartwheel galaxy. The Cartwheel, located about 500 million light-years from Earth in the constellation Sculptor in the southern sky, is a rare type of galaxy that astronomers call a ring galaxy. Scientists believe the Cartwheel was a typical spiral galaxy long ago, similar to our Milky Way. This galaxy formed due to a high-speed collision about 400 million years ago. The Cartwheel comprises two rings, a bright inner ring and a colourful outer ring. Both rings expand outward from the centre of the collision like shockwaves. However, despite the impact, much of the character of the large, spiral galaxy that existed before the crash remains, including its rotating arms. This leads to the "spokes" that inspired the name of the Cartwheel Galaxy, which are the bright red streaks seen between the inner and outer rings. 

These brilliant red hues, located not only throughout the Cartwheel but also in the companion spiral galaxy at the top left, are caused by glowing, hydrocarbon-rich dust. In this near- and mid-infrared composite image, MIRI data are coloured red, while NIRCam data are coloured blue, orange, and yellow. Webb's observations capture the Cartwheel in a very transitory stage. Given these two competing forces, the form that the Cartwheel Galaxy will eventually take is still a mystery. 

Rishona Chopra
Grade VI
Gyanshree School

Reference: Galacita Monthly Space Magazine


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