Scientific Discoveries
How did India's ASTROSAT space observatory contribute to our understanding of dwarf galaxy formation and evolution?
India's ASTROSAT made a groundbreaking discovery by observing the formation process of dwarf galaxies located 1.5 to 3.9 billion light years from Earth. Using its Ultraviolet Imaging Telescope, researchers captured 17 hours of data showing star-forming complexes on the outskirts of these galaxies and documented material moving inward from the outer edges toward the center of 11 dwarf galaxies. This observation provides crucial evidence for how dwarf galaxies, containing only a few billion stars, evolve into mature systems like the Milky Way with 200-400 billion stars. The study, published in Nature and led by astronomers from India, the US, and France, represents the first concrete documentation of this evolutionary process. The findings are significant because they address current gaps in theoretical models of galaxy evolution and demonstrate ASTROSAT's remarkable capabilities as a UV observatory for probing galaxy assembly processes.
Watch clip answer (02:49m)
WION
00:05 - 02:54
How do dwarf galaxies assemble and grow over time, and what new insights has India's ASTROSAT telescope revealed about this process?
India's ASTROSAT telescope has provided groundbreaking observations showing that dwarf galaxies grow through a fascinating inward spiral process. Using the Ultraviolet Imaging Telescope (UVIT), researchers discovered that young, large star-forming clumps form on the periphery of these galaxies and then spiral inward toward the galaxy's center over approximately a billion-year timescale. This discovery challenges existing theoretical models of galaxy evolution by revealing the "live formation" of distant dwarf galaxies. The study, led by researchers from multiple countries, demonstrates how material moves from the outskirts to contribute to galaxy growth. ASTROSAT's exceptional resolving power and deep field imaging capabilities were crucial in identifying these star-forming regions and tracking their movement patterns. These findings significantly advance our understanding of cosmic evolution and highlight the diversity in dwarf galaxy properties that current models struggle to explain.
Watch clip answer (01:10m)WION
02:03 - 03:14
How extensive is NASA's current space exploration program and what is the relationship between science and exploration?
NASA currently operates 140 active missions across the solar system, demonstrating the unprecedented scope of human space exploration. The relationship between science and exploration is symbiotic - scientific knowledge enables more ambitious exploration missions, while exploration activities generate new scientific discoveries and data. This interconnected approach allows NASA to continuously push the boundaries of human knowledge while advancing our capabilities to explore deeper into space, ultimately benefiting humanity through technological innovations and scientific breakthroughs.
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NASA
01:35 - 01:48
Why does the Moon appear larger when it's positioned on the horizon compared to when it's high in the sky?
The Moon horizon illusion is likely explained by the Ponzo illusion, where our visual perception is influenced by our experience with distant objects. Throughout our lives, we observe that objects like clouds, planes, and ships appear to shrink as they move toward the horizon. However, the Moon maintains its actual size regardless of its position in the sky. To reconcile this inconsistency, our minds compensate by making the Moon appear larger when it's at the horizon. While this is a popular hypothesis among several theories involving atmospheric effects and cognitive biases, scientists are still conducting research to reach a definitive consensus on this fascinating optical phenomenon.
Watch clip answer (00:29m)
NASA
00:38 - 01:08
Why does the Moon appear larger when it's on the horizon compared to when it's high in the sky?
The Moon appearing larger on the horizon is primarily an optical illusion rather than a physical phenomenon. Contrary to common assumptions, the Moon is actually about 1.5% farther away when on the horizon and atmospheric refraction slightly compresses its appearance rather than magnifying it. This same illusion affects constellations, which also appear larger near the horizon. The phenomenon has puzzled scientists since Aristotle's time, and while atmospheric effects have been ruled out as the primary cause, researchers continue investigating how our visual perception and psychological factors contribute to this enduring celestial mystery.
Watch clip answer (00:13m)NASA
00:25 - 00:38
Why does the Moon appear larger when it's positioned near the horizon compared to when it's higher in the sky?
The phenomenon of the Moon appearing larger near the horizon remains an unsolved scientific mystery that has puzzled experts for over 2,000 years, dating back to Aristotle's observations. Despite extensive research and ongoing scientific experiments, there is still no definitive consensus on the exact cause of this optical illusion. While scientists have proposed various theories including atmospheric effects and the Ponzo illusion (a visual perception phenomenon), the complete explanation continues to elude researchers, making it one of astronomy's most enduring puzzles.
Watch clip answer (00:17m)NASA
00:05 - 00:22