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astrodaily1. Is time travel possible?  We have discussed in the past how it is theo

Is time travel possible? We have discussed in the past how it is theoretically possible to travel into the past by utilizing wormholes—bridges that connect disparate points in spacetime. Although the mathematics of general relativity can be applied to suggest that such time travel may be possible, a more philosophical approach reveals paradoxes that may discredit the entire idea. Temporal paradoxes are logical contradictions that arise when the past is altered in any way. The well-known “grandfather paradox” plays with the idea that if a time traveler were to go back into the past and kill their own grandfather, it would prevent their very own conception and existence. Therefore, there would be no one in the future to have gone back in time! A classic paradox. Also known as a “consistency paradox”, this same idea can be applied to any action that alters the past. Since it is absolutely true that the past occurred in a certain way to lead to one’s existence, it is logically contradictory (impossible) for the past to have occurred in any other way. Therefore, even if we were able to travel back in time using a wormhole, the traveler(s) would necessarily have to allow the past to play out as it had previously. In “A Brief History of Time”, Stephen Hawking offers a possible resolution to this paradox. He states that everything that happens in spacetime must be a consistent solution to the laws of physics, meaning that you could not go back in time unless history showed that you had already arrived in the past and had not killed your grandfather (or committed any other act that alters the present). Essentially saying that if time travel is possible, it must be impossible to change recorded history. This conclusion has other interesting consequences for the concept of human free will, which we will discuss in the near future. Photo credit: Curiosity, phys.org #astronomy #space #science #wormhole #gravity #time #travel #physics #blackhole #nasa #read #mlk #education #mind #learn

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astrodaily1. Yesterday we discussed the largest volcano (and mountain) in the solar

Yesterday we discussed the largest volcano (and mountain) in the solar system—Olympus Mons. At approx. 27,000 meters (88,600 feet) in height, Olympus Mons dwarfs all other surface features on the terrestrial planets (see post from yesterday for explanation). Along with producing some of the largest topographic features, volcanism can produce some of the most incredible sights in the solar system, especially on our home planet. With active plate tectonics and an abundance of internal heat, planet Earth has lava, pyroclastics, and volcanic gases constantly escaping through vents at its surface. Our satellites and spacecraft in low-Earth orbit give us incredible perspective on the clouds of gas and ash that rise from these openings in the crust. Once material makes its journey from the depths of our planet to the surface, it immediately becomes vulnerable to the atmosphere. Ultimately these volcanic rocks are broken down, transported, deposited, re-solidified, and possibly even re-erupted from a new volcano millions or billions of years later—all part of the beautiful, never-ending rock cycle. Photo Credit: NASA/ISS #geology #volcano #space #science #nasa #learn #astronomy #read #earth #mars #education #atmosphere

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astrodaily1. Sunrise, mid-day, and sunset over the largest mountain in the solar sy

Sunrise, mid-day, and sunset over the largest mountain in the solar system. Olympus Mons, located in the western hemisphere of Mars, is a massive shield volcano that is approx. 25 km (16 mi) high, making it nearly three times as tall as Mount Everest (the tallest mountain on planet Earth). Also, the massive diameter of 624 kilometers (374 miles) makes the volcano about the same size as the state of Arizona. The extraordinary size of Olympus Mons is likely because Mars lacks mobile tectonic plates. On Earth, we have tectonic plates that essentially slide around on a mechanically weak subsurface layer known as the asthenosphere. A combination of sea-floor spreading ridges and plate subduction keeps the plates of Earth consistently moving. As a result, when mantle-sourced plumes of molten rock (“hotspots”) rise into the overlying mobile tectonic plate, the associated volcanism at the surface migrates over time (i.e. Hawaii). During the eruption of Olympus Mons, the crust of Mars remained fixed over a stationary hotspot, and the volcano continuously discharged lava until it reached an enormous height. Olympus Mons has been heavily studied by planetary scientists, and will continue to give us clues to the geologic history of the red planet. Photo credit: NASA #mars #space #science #earth #geology #volcano #education #planet #learn #read #nasa #astronomy

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astrodaily1. Wormholes are theoretical structures that link two or more separate po

Wormholes are theoretical structures that link two or more separate points in spacetime and have been popularized as potential conduits for time travel. There have been many theoretical propositions for how wormholes could facilitate time travel. One of my favorites involves traveling through a traversable wormhole that exits into a region of space with a higher gravitational field than was present at the wormholes entrance (preferably an extreme gravity environment, ex. near a black hole). Time dilation as a direct consequence of increased gravity would lead to slower aging at the exit of the wormhole. Put another way, the exit of the wormhole would be “younger” than the entrance when observed from the outside (remember that the time dilation would not be detected by the traveler, as time is only warped for an outside observer). Therefore, two synchronized clocks would remain synchronized for the traveler. However, for an observer, the traveler would exit the younger end of the wormhole at a time when it is the same age as the “older” entrance, effectively going back in time. I know that I still don’t have a full understanding of general relativity, and it has only been through rather extensive reading and writing that I have begun to comprehend it. It serves as a good reminder for me that virtually all things worth understanding or learning are difficult. I don’t think I have obtained any significant meaning from goals or concepts that are easily obtained. Whether you’re learning to ski or solving differential equations, the process becomes easier once you recognize that it is supposed to BE HARD. Photo credit: ESO, NASA #science #gravity #time #space #wormhole #philosophy #meaning #learn #math #life #education #astronomy #think

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astrodaily1. As far as we know, we consist entirely of atomic matter.  There is no

As far as we know, we consist entirely of atomic matter. There is no evidence to suggest that there is a metaphysical “self” contained within the meat suits that we call our bodies. People find this conclusion of no soul unsettling, atheistic, and cold. I view it quite the contrary. The realization of the illusion of self is one that I am not sure I have come to fully understand, but my initial exploration of it has been rather exciting. A majority of the world’s religions reassure their followers that there is something sacred about them as a person—that they each have a unique self or soul that will exist for all eternity. People are afraid of ceasing to exist, and that seems like a fundamental reason why many subscribe to religious teachings. I don’t understand why existing eternally is longed for by our species. It seems to me that one of the fundamental truths of existence is that impermanence is what gives any object meaning. So why do we subscribe so quickly to the idea of an ever-lasting soul? Why would you want your conscious soul to be immortal? If you have infinite time to experience after death, why would you even start doing anything if it could just be put off for 20 trillion years with no consequence? It seems crystal clear to me impermanence is what gives anything meaning—love, music, a flower, consciousness. For me, recognizing that my consciousness will most likely not transcend my body after death makes each moment so much more rich and meaningful. I do not write this as a criticism of your beliefs, but simply as a presentation of mine. I enjoy exploring religious teachings, but do not feel comfortable concluding that one of them is truer than another. One of the worst possible things we can do as a species is close our minds to possible explanations of the cosmos that don’t align with what we believe. Regardless of your beliefs, we are a collection of atoms studying atoms. It’s one of the most ridiculous truths of the universe we occupy. All love. Photo credit: NASA, HST; Wikipedia #science #religion #god #think #space #astronomy #philosophy #read #write #mind

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astrodaily1. The unit of distance known as the “light year” is used extensively in

The unit of distance known as the “light year” is used extensively in the field of astronomy/astrophysics. As we have discussed in the past, it is easy to take things for granted when they are always there or consistently used. Repetition breeds indifference. As I was falling asleep last night, I was thinking about how ridiculously far one light year actually is, and pondering the implications of understanding what it actually means. At 1.07 billion km/hr (671,000,000 mi/hr), light travels through our universe in all directions unstoppably and at perfectly constant speed. Since human minds do not prefer to deal with such large numbers, we created the unit of distance known as the light year—the distance that light travels in one calendar year. Some examples help to comprehend exactly what this means. The closest star to Earth (other than the Sun) is Proxima Centauri, located approx. 4.22 light-years from Earth. This means that the moment a light-wave leaves Proxima Centauri, it will not arrive on Earth for 4.22 calendar years. The light wave is traveling at the absurd speed of 1 billion km/hr and it still takes 4+ years to make the journey! Holy sh&*! Understanding the speed of light also has interesting implications with regards to the passage of time. In astrophysics, we most commonly discuss vast cosmic distances like millions or billions of light-years. Extending the explanation above, this means that it takes light waves millions or billions of years to make the journey to our Earth-based telescopes. The sources of electromagnetic radiation (black holes, pulsars, quasars, globular clusters, etc) that lie billions of light-years away no longer exist, as we are seeing them as they were billions of years ago. Consequently, we are looking back in time—we are time traveling. Many of the objects we observe throughout the cosmos began their journey towards our telescopes millions to billions of years before our solar system had even formed! Photo credit: NASA, HST #astronomy #science #space #light #physics #learn #read #write #think #galaxy #earth

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astrodaily1. People seem to be immensely interested in black holes, general relativ

People seem to be immensely interested in black holes, general relativity, spacetime, time dilation, etc. I would love to answer (to the best of my ability) any questions you may have on these concepts. They are tough! This artistic representation shows what happens when a star is so massive that the escape velocity is greater than the speed of light. Black holes are the result of a large-mass star reaching the end of its stellar evolution. If a star’s mass is approx. 3 times greater than our Sun, even the nuclear pressure of compressed neutrons cannot offer sufficient resistance to the force of gravity. The star continues to collapse to become a black hole, a region of space with such a strong gravitational field that nothing can escape. Photo credit: NASA #astronomy #astrophysics #space #star #nebula #nasa #learn #blackhole #gravity #time #think #science #read

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astrodaily1. Why is there something rather than nothing? Where did we come from?  W

Why is there something rather than nothing? Where did we come from? Where are we going? What is right? What is wrong? What is the purpose of life? Don’t you find it incredible that we rise from slumber each morning with essentially all of life’s biggest questions unanswered? It seems to me that a more appropriate response would be crippling fear of our staggering existential ignorance. Yet people are able to depart their shelter in the morning and contribute in varying ways to the society that sustains them, regardless of the uncertainty and suffering that inevitably awaits. I leave my home in the morning and occasionally find myself in absolute awe that the world is able to function as it does. I am very curious as to how our species is able to press on considering how little we know about our existence. Maybe it is because we are not intelligent enough to actually comprehend how little we know, or possibly it is because deep within our evolutionary roots lies a burning desire to uncover the truth. Regardless, I think the overall stability of the world is a direct result of there being more good than evil on it. It is quite possible that we may never answer life’s biggest questions, but that should not deter you from attempting to answer them. Do you really have anything better to do? Photo credit: NASA, Voyager #science #space #philosophy #learn #nasa #jupiter #planet #meaning #read #write #learn #education

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astrodaily1. Everyone experiences some form of anxiety. Anxiety is defined as \"a fe

Everyone experiences some form of anxiety. Anxiety is defined as "a feeling of worry, nervousness, or unease, typically about something with an uncertain outcome". The final two words of this definition explain why anxiety is ubiquitous. Nearly every single thing that you do each day has an uncertain outcome. As all humans know too well, even the most intricate, thought-out plans can produce unexpected results. It is this uncertainty that is the root of anxious feeling. Recognizing that feelings of anxiety are a shared component of the human experience can help mitigate them. One must also recognize that uncertainty is not only the root of anxious feelings, but the root of life itself. What would life be without uncertainty? Imagine if you actually knew what the result of your actions would be before you acted. It would completely strip life of its meaning. In his work “The Book”, Alan Watts states that “..the more surely the future is known, the less surprise and the less fun in living it”. Isn’t that funny? That one of the sensations that our species finds most unpleasant actually arises from what gives our lives meaning. Approached from this perspective, it is easier to embrace feelings of uncertainty, and allows one to recognize anxiety as a powerful reaction to the overwhelming responsibility of the individual. This recognition can allow you to minimize feelings of anxiety and take control of your life. Photo credit: NASA #astronomy #meaning #astrophysics #life #think #love #space #science #philosophy #read #write

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astrodaily1. One of the 21st century conversations that I find most interesting and

One of the 21st century conversations that I find most interesting and intellectually stimulating is that surrounding artificial intelligence (AI). The broad definition of ‘artificial intelligence’ that I find most accurate refers to AI as “any device that perceives its environment and takes actions that maximize its chance of successfully achieving its goals”. With the unprecedented technological advances that have taken place over the past few decades, the topic of AI is becoming more and more relevant and the creation of a super-intelligent machine may lie in the near future. There are dozens of equally fascinating discussions to be had regarding AI, but the one I have found most interesting is what is known as the ‘control problem’. Also known as ‘the alignment problem’, this philosophical concept addresses the importance and difficulties of making sure that a superintelligent machine has end goals that align with the intentions of its creators. From my reading, it seems that it would be terrifyingly easy to create an AI that either misinterprets or disregards our initial commands—resulting in a future that is far from one that maximizes human well-being. Essentially all the top AI researchers recognize that if a superintelligence is not created extremely carefully, it could have devastating implications for our species and planet. The reason that this problem is particularly interesting is that we must get it right the first time—there are no second chances. “Recursive self-improvement” will essentially be an AI’s ability to reprogram and improve itself—we do not know the limit to this, and it would likely be exponential improvement. A recursively self- improving AI will leave us in the dust intellectually and will likely be able to do every single thing better than the best human in a given category. If its initial goals do not align perfectly with what maximizes the well-being of Homo sapiens, we will have likely created our own destroyer. Photo credit: NASA/ESA, HST #astronomy #physics #ai #philosophy #future #technology #space #science #learn #education #computer

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astrodaily1. The range of electromagnetic wavelengths seen by the human eye is very

The range of electromagnetic wavelengths seen by the human eye is very small. With advances in technology, we are now able to gain great insight into the universe by studying it in the wavelengths not detected by the naked eye. NASA’s Solar Dynamics Observatory (SDO) has instruments capable of capturing a wide range of wavelengths. This colorful image shows the Sun in eight different wavelengths, captured over a three-minute period. From top to bottom, these wavelengths include: 94, 131, 171, 193, 211, 304, and 335 Ångström. Visible light images of the Sun commonly capture wavelengths of ~4500 Ångström, so these images expose more detailed features at a very small wavelength. For those curious, the Ångström is a unit of length equal to 1.0e-10 m. I encourage you to practice some simple math by converting the measurements above to their meter equivalents. It will help put in perspective how short these wavelengths actually are. The collages in photos two and three contain a total of 10 different wavelengths, and the fourth image shows a solar flare in four different wavelengths. The final image is a fantastic visualization of how large solar processes are compared to our home planet. Photo credit: NASA, SDO #sun #science #solar #space #star #learn #education #astrophysics #physics #math

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astrodaily1. A magnetosphere is the region around a planet dominated by the planet'

A magnetosphere is the region around a planet dominated by the planet's magnetic field. Excluding Mars and Venus, every planet in our solar system has a significant magnetic field. This magnetosphere is what enables the incredible phenomena of aurora at the poles of a planet. During solar storms, our Sun violently ejects plasma-ionized particles into space, which eventually reach the planets and create the aurora. After the solar particles are trapped in a planets field lines, they travel to the poles and collide with gases in the upper atmosphere. On Earth, aurorae are commonly green, which is a result of the trapped particles interacting with the relatively large amount of oxygen in our atmosphere. On other planets, the colors can be drastically different due to the different atmospheric composition. The first two images here show Saturn’s aurora in the ultraviolet wavelength. Although the blue color is dramatic and effective, it is likely that excitement of the visible spectra would result in an observer seeing a red color like that seen in Image 3. This red color is a result of Saturn’s predominately hydrogen and helium-rich atmosphere. 〰️〰️〰️ Photo credit: Cassini Spacecraft, NASA #astronomy #astrophysics #space #nasa #hubble #science #cosmos #planet #saturn #learn

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