Albert Einstein’s theory of general relativity, which describes gravity as the curvature of spacetime by mass, finds a practical testing ground in the orbit of star S2 around Sagittarius A* (Sgr A*), the supermassive black hole at our galaxy’s center. S2 orbits Sgr A* with a period of about 16 years, reaching speeds over 5,000 km/s and experiencing significant gravitational effects due to its proximity to the black hole. This setup allows astronomers to observe and confirm predictions of general relativity, such as orbital precession, and explore potential new physics. The close approaches of S2, especially notable in mid-2018, provide critical data to refine our understanding of spacetime and gravity under extreme conditions.
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Launched by NASA on September 5, 1977, Voyager 1 was designed to study the outer planets. After its primary mission, it became the first human-made object to enter interstellar space in 2012, exploring the region beyond our solar system!
In November of the previous year, Voyager 1 began sending back unintelligible data due to a faulty computer chip. NASA’s team at the Jet Propulsion Laboratory successfully addressed this by reprogramming the spacecraft to bypass the malfunction. This fix restored coherent communication, although efforts to resume transmission of scientific data are ongoing.
Despite being over 15 billion miles away, communication with Voyager 1 involves a 22.5-hour one-way signal delay. The spacecraft continues to send back data from the depths of interstellar space, maintaining its role as humanity’s most distant journey.
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The impending budget cuts proposed by Congress pose a significant threat to one of the major X-ray observatories, crucial in black hole research. Chandra observatory requires approximately $64 million annually to remain operational is facing financial jeopardy. The budgetary constraints are stark when compared to international defense expenditures, as highlighted by a popular YouTuber’s observation that this sum equates to the cost of one out of fifty jets recently gifted to our greatest ally in the Middle East. The potential reduction in funding could severely weaken the observatory’s operational maintenance to continue its vital scientific contributions, underscoring a contentious debate over national spending priorities and the valuation of scientific endeavor against geopolitical interests and crimes .
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Living on Uranus would need advanced technology that would be able to sustain the extreme environment. Due to its extreme axial tilt of about 98 degrees, a single day on Uranus, same to 17 Earth hours. This would not bring significant changes in light or darkness like on Earth. Instead, surprisingly each pole experiences 42 years of continuous sunlight followed by 42 years of darkness, creating prolonged periods of day and night over the course of a Uranian year. This tilt also contributes to a magnetic field, vastly offset from the center and tilted, creating complex magnetic interactions with the solar wind. The ring system discovered by Voyager 2 of Uranus would appear as narrow, faint arcs encircling the planet. The atmosphere, predominantly composed of hydrogen, helium, water, ammonia, and methane ices, would present a frigid and hostile environment, with temperatures plunging to around -224ยฐC, the coldest planetary atmosphere in our solar system. Uranus’s moons would orbit distantly in this icy space. As our technological capabilities advance, we may someday not only learn more from but also potentially inhabit the extreme conditions of places like Uranus.
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On our expedition to Mars, a key strategy to determine if life exists or ever existed on the planet involves searching for chemotrophs. These small organisms thrive in harsh environments like in deep ocean volcano without the need for sunlight, making them ideal candidates for life on Mars. Chemotrophs could potentially exist beneath the Martian surface, protected from harsh surface conditions and radiation, and assisted by abundant oxygen. The subsurface environment of Mars may offer water in the form of ice or brine and chemical energy sources, essential for life. By exploring underground reservoirs, caves, or drilling into the Martian subsurface, we could uncover signs of chemotrophic life, helping us to understand if life on Mars did not progress past a pre-evolutionary phase or if life once thrived on the planet.
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Have you ever thought about how Technetium, a super heavy is made and how do we know? Stellar nucleosynthesis is a cornerstone subject in our research for the star life cycle. The process by which stars produce heavier elements from lighter ones through nuclear fusion is a central force that forms Technetium. Moreover, we now understand that hydrogen was turned to helium by nuclear fusion and further new atoms were made the same way. The evidence we gain from this is based on radioactivity and decay.
Radioactivity acts as a time machine for determining age. It is known as radiometric dating, and it measures the decay rates of radioactive isotopes within rocks and minerals on earth. Radiometric dating involves measuring the original unstable radioactive isotope and the decay isotopes in a mineral or rock. By comparing these two, weโll know the half-life of the parent isotope, the time it takes for half of the parent isotope to decay into the daughter isotope, and this time is used to estimate the age of the rock. This technique has been used in understanding the timeline of events in the solar system, including the formation of planets and the age of the Earth.
To tell you about an example of use of this technique, consider how we determine the age of the Earth. This method analyzes the ratio of uranium isotopes to their lead decay products in zircon crystals found in ancient rocks. While people were searching for valuable minerals, the oldest zircons was found in the Jack Hills of Western Australia, which have been dated to approximately 4.4 billion years. This provided evidence for the age of the Earth’s crust. The more precise age of earth was estimated to be 4.543 billion years. Thanks to these techniques we can understand the evolution of earth.
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In the quest to understand the natural world, astronomers heavily rely on light as a source of information. This helps in determining the movement of the Earth. Indeed, alongside Foucault’s Pendulum, Stellar Parallax, and the Coriolis Effect, we observe light not only from planets within our solar system but also from distant stars to hypothesize that the Earth is in motion. Our basic comprehension is supported by our understanding of the visible part of the light spectrum. Receiving light of a lower frequency, which appears reddish, indicates that the light source is moving away from us. Conversely, light of a higher frequency, appearing blue, suggests that the source is approaching us. When observing the light from stars and galaxies, we can detect small shifts that prove the earth is not stationary. This discovery, made later, enhanced our understanding of the universe’s creation and opened new doors in astronomy. By measuring the degree to which a light’s wavelength has been stretched, we can estimate the speed of distant objects relative to Earth. Furthermore, with Khan academy’s video on Hubble’s Law, we can calculate the distances to these stars or galaxies based on the relationship between their speed and distance.
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Isaac Newton’s (1642-1727) contributions to astronomy are vast and form the basis for our modern understanding of the field. His work laid the foundation for understanding the motion of planets and their gravitational interactions with each other and with their satellites. Beyond the astronomical significance of Isaac Newton’s work, the development of calculus represents another major advancement in our ability to understand and compute astronomical phenomena. It has expanded our capabilities, allowing for precise analysis of motion, change, and the dynamic behavior of celestial objects. Additionally, during Newton’s lifetime, a major epidemic of the bubonic plague, also known as the Black Death, occurred. This event personally affected Newton, as his university was under lockdown, similar to what occurred during COVID-19. Historians refer to this period as a “year of wonders” because it was during this time that he made significant discoveries in calculus, physics, and astronomy. An important figure who flourished in the Ottoman Empire during Newton’s lifetime was Katip รelebi (1609-1657). Although his interests were somewhat similar to Newton’s, รelebi primarily worked in theology and Islamic jurisprudence, with a focus on history. Among other Islamic scientists, he endeavored to create an encyclopedic dictionary of Islamic literature.
From this learning experience, I gained insight into the context surrounding individuals who endeavored to understand and scientifically investigate the world. Despite facing resistance during their lifetimes, they are now recognized as pioneers of the disciplines that underpin our technological advancements.
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How did we come up with the names and positions of the constellations in the night sky? This is a question I will be answering in this blog, and I hope to contribute to the diverse themes presented in the book. My focus is on the Arabic contribution to the naming of the stars and constellations. The history of Islamic astronomy is marked by the development of astronomy across three continents. As Arabic was the common language of that era, most knowledge was acquired in Arabic. Scholars from Central Asia, the Middle East, to North Africa, and most notably Al-Andalus (modern-day Iberian Peninsula), observed the sky as a means of understanding God’s creation and strengthening their faith in their respective religions. Among these scholars was the Persian polymath Abd al-Rahman al-Sufi. I will point out two constellations from his book “The Book of Fixed Stars,” written around 964 AD. The first example is al-Jady, commonly known as the Algedi constellation, which translates from Arabic as “the Goat.” Its scientific name is Alpha2 Capricorni, a southern triple star system in Capricorn. The second example is the constellation commonly known as Albali. Its Arabic name is al-Bฤliสฝ, translating to “the Swallower.” Scientifically, it is identified as the single star Epsilon Aquarii in Aquarius.
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Greetings,
My name is Muhammad Israr. I have a long-standing interest in night sky photography, which led me to take this class. Additionally, as someone who enjoys reading about history, I’m particularly fascinated by the ancient Muslim astronomers. Their legacy inspires me as I study astronomy at Vanderbilt University, exploring the universe and pursuing my passion, much like those historical figures once did. The pic bellow is one of my works. It is a picture of Falls Creek state park of Tennessee.