Reaching light

Reaching the Speed of light

Is interstellar travel doomed to remain in the realm of science fiction with faster than light travel and infinite improbability drives? Never mind warp speed, is light speed even possible? Technically no Light is massless and travels a little over 1 billion km/h Since spacecraft are not massless you need energy to accelerate as you keep gaining speed, you’ll need increasingly larger amounts of fuel. Eventually, even tiny gains in acceleration require huge amounts of energy Getting to exactly one hundred percent light speed would require an infinite amount of energy which is why it’s an impossible goal Before we look at how close we can get to the speed of light .

Let’s consider what we’ve accomplished so far When it comes to space travel, everything starts with a rocket still the best way we know of to literally get our feet off the ground rockets give spacecraft that initial massive boost to escape Earth’s gravity t’s the first step in getting people to the moon sending probes to the planets our sun and even the edge of our solar system apollo 10, the dress rehearsal for Apollo 11 never landed on the moon, but at reentry it did set the world record for the fastest manned spacecraft at just under 40,000 km/h in order to get all the way to the moon, it needed the help of Saturn V still the most powerful rocket ever launched The New Horizons probe, hitching a ride on the Atlas V holds the record for fastest launch velocity at over 58,536 km/h that was also the first spacecraft to reach Pluto in 2015 sending back the first detailed images ever taken of Pluto.

Launched in 1977, Voyager 1’s mission was the exploration of Jupiter and Saturn and once complete to leave the solar system entirely It couldn't do it with rocket power alone so it used gravity assists at Jupiter to slingshot to Saturn and again at Saturn to fling itself out to the edge of the solar system Voyager 1 reached a top speed of 62,000 km/h but it still took over 30 years to reach interstellar space in 2012. In 1976, the Helios-2 probe set off to study the sun and the interplanetary medium To do so they were put in highly elliptical orbits with the Sun at one end and all the way out to the Earth's orbit at the other Each time it approached the Sun the massive gravitational force speed it up to a record setting speed of 253,000 km/h the fastest any spacecraft has ever travelled Solar Probe Plus is study the corona and outer atmosphere of the sun.

Over the course of seven years multiple gravity assists will be used at Venus to bring it into an orbit around 7 times closer to the sun than Helios With that close of an orbit it will crush the Helios record with a top speed of just under 725,000 km/h even still, that’s just a meager .07% the speed of light and would take over 6,000 years to travel 4 and a quarter light years to get to Proxima Centauri the closest star to our own In 2016 a planet, Proxima b, was discovered around the star. It’s probably rocky like the Earth and in the right orbit to be potentially warm enough for liquid water on the surface if it has any. This makes it an excellent target for the first interstellar spacecraft staying in the realm of current or near future technology only can we improve on that speed?

Ion propulsion is currently employed in some satellites but most notably, the Dawn spacecraft which studied the asteroid Vesta and the dwarf planet Ceres Inside the thruster, electrons bombard neutrally charged atoms ausing them to lose electrons and become positively charged ions Thrust is produced as they are shot out in an ion beam the resulting thrust is miniscule but since it’s fuel supply can last for years, unlike a rocket that tiny amount of thrust keeps compounding on itself and in time, it can potentially reach speeds of up to 324,000 km/h, although no spacecraft currently has while not the fastest it’s a practical method to study multiple celestial bodies in one mission an exciting potential for solar system exploration.

In the 1970s, the British Interplanetary Society conducted a study Project Daedalus for an unmanned fusion propelled interstellar spacecraft With help from the Tau Zero foundation in 2009 hey initiated Project Icarus to update the concept with the Ghost team’s design winning the internal competition in 2013 for propulsion, Ghost uses Inertial Confinement Fusion Small fuel pellets are shot into a fusion chamber Lasers bombard each pellet from all sides, compressing it then one final laser pulse shoots into the core, igniting the fusion process The resulting plasma is expelled from the ship, producing thrust The older Daedalus design would have reached a remarkable 12% light speed Ghost can only get to 2.33% light speed reaching Proxima Centauri in around 186 years while much slower,  Ghost allows for deceleration at the star for scientific study using it’s own fusion engine and a magnetic sail 400 km in diameter. 

Ghost also uses a more practically sourced fuel Deuterium and Tritium while Daedalus used the more efficient combination of Deuterium and Helium-3. Unfortunately, Helium-3 is too rare and inaccessible on Earth You would have to mine a gas giant like Jupiter or possibly the moon to get enough fuel. Though it’s the fusion process itself that may be the biggest challenge We have yet to achieve a sustained fusion reaction in the lab until we figure that out, these ships won’t leave the ground weighing in at 1.4 million tonnes and over a kilometer long Ghost couldn’t launch from Earth it would have to be assembled in parts.

This is no small task as The International Space Station, the largest spacecraft ever built is 450 tonnes and 109 meters long, peanuts compared to Ghost Since almost all of the mass of a fusion spacecraft is fuel imagine not having to carry any with you Enter the solar sail IKAROS is a small solar sail spacecraft built by the Japanese space program JAXA Launched in 2010, it was the first successful demonstration of solar sail propulsion similar to ion propulsion sunlight results in only a small amount of thrust but it keeps compounding on itself and only stops when the spacecraft is too far from the sun. The total thrust is determined by the surface area of the sail versus the mass of the spacecraft With a big sail you can catch more light With less mass, the light can push you faster There’s also more solar energy imparted on the spacecraft the closer you can get to the sun as long as you don’t burn up in the process.

Unfortunately this may not be good enough to get to another star within a lifetime It would take a 1 kg spacecraft with a 1km x 1km sail travelling extremely close to the sun about 100 years to reach Proxima Centauri But we may be able to improve on this Breakthrough Starshot is another proof-of concept project to design an unmanned laser propelled spacecraft. A mothership containing thousands of nanocrafts will be launched into orbit This allows for redundancy in case of failure and a variety of payload options These tiny, gram-scale nanocraft have a sail only 4 meters to a side and just a few hundred atoms thick.

The Light Beamer is a ground based array of lasers that combine together in a single beam to propel each nanocraft to 20% light speed within minutes. At that speed, they could reach Proxima Centauri in as little as 20 years While just a flyby mission they could get close enough to Proxima b to take pictures with enough detail to see continents and oceans if it has any While the team doesn’t see any deal breakers that could stop the project that’s not to say there won’t be any challenges especially building the light beamer at 100 gigawatts, the array would be 100 times more powerful than a nuclear power plant It will also need to contend with the scattering effects of the atmosphere as an orbital laser of this scale is too expensive Speaking of which, the projected cost is nearly 10 billion dollars about half of NASA’s 2016 budget But it does start to look like a bargain compared to the $100 billion dollar cost of the International Space Station Breakthrough Starshot may represent not only the most practical interstellar spacecraft but at 20% light speed it would be the fastest

End of the Universe

How the Universe

Possibly Ends 

 We know about our universe’s past : the Big Bang theory predicts that all matter, time, and space began in an incredibly tiny, compact state about 14 billion years ago. And we know about the present: scientists observations of the movement of galaxies tell us that the universe is expanding at an accelerated rate. But what about the future? Do we know how our universe is going to end? Cosmologists have three possible answers for this question, called the Big Freeze, the Big Rip and the Big Crunch.

 To understand these three scenarios, imagine two objects representing galaxies. A short, tight rubber band is holding them together— that’s the attractive force of gravity. Meanwhile, two hooks are pulling them apart— that’s the repulsive force expanding the universe. Copy this system over and over again, and you have something approximating the real universe. The outcome of the battle between these two opposing forces determines how the end of the universe will play out. 

The Big Freeze scenario is what happens if the force pulling the objects apart is just strong enough to stretch the rubber band until it loses its elasticity. The expansion wouldn’t be able to accelerate anymore, but the universe would keep getting bigger. Clusters of galaxies would separate. The objects within the galaxies– suns, planets, and solar systems would move away from each other, until galaxies dissolved into lonely objects floating separately in the vast space. The light they emit would be redshifted to long wavelengths with very low, faint energies, and the gas emanating from them would be too thin to create new stars. The universe would become darker and colder, approaching a frozen state also known as the Big Chill, or the Heat Death of the Universe. 

But what if the repulsive force is so strong that it stretches the rubber band past its elastic limit, and actually tears it? If the expansion of the universe continues to accelerate, it will eventually overcome not only the gravitational force – tearing apart galaxies and solar systems– but also the electromagnetic, weak, and strong nuclear forces which hold atoms and nuclei together. As a result, the matter that makes up stars breaks into tiny pieces. Even atoms and subatomic particles will be destroyed. That’s the Big Rip. 

What about the third scenario, where the rubber band wins out? That corresponds to a possible future in which the force of gravity brings the universe’s expansion to a halt— and then reverses it. Galaxies would start rushing towards each other, and as they clumped together their gravitational pull would get even stronger. Stars too would hurtle together and collide. Temperatures would rise as space would get tighter and tighter. The size of the universe would plummet until everything compressed into such a small space that even atoms and subatomic particles would have to crunch together. The result would be an incredibly dense,hot, compact universe — a lot like the state that preceded the Big Bang. This is the Big Crunch. Could this tiny point of matter explode in another Big Bang? Could the universe expand and contractover and over again, repeating its entire history? The theory describing such a universe is known as the Big Bounce. In fact, there’s no way to tell how many bounces could’ve already happened— or how many might happen in the future. Each bounce would wipe away any recordof the universe’s previous history. 

Which one of those scenarios will be the real one? The answer depends on the exact shape of the universe, the amount of dark energy it holds, and changes in its expansion rate. As of now, our observations suggest that we’re heading for a Big Freeze. But the good news is that we’ve probably got about 10 to the 100th power years before the chill sets in — so don’t panic it's gonna take a long time. 

Gravitation Wave

The Gravitational

 Waves

Gravitational waves are ripples in the fabric of spacetime, predicted by Einstein’s laws of general relativity, but they are incredibly difficult to detect. To see them you need a detector that can accurately measure distances 10,000 times smaller than a proton. Thats crazy! That’s like trying to measure the distance from our Sun to the nearest star to accuracy of the width human hair. But we have a technology on Earth that can do that:  ALIGO the Advanced Laser Interferometer Gravitational-wave Observatory, and back in November 2015, on a Monday morning, LIGO detected the first gravitational wave that humans have ever directly observed. Where they came from and what this means for space science is nothing short of mind blowing!

A long long time ago, in a galaxy far faraway. 1.3 billion years ago and1.3 billion light years away, two black holes were stuck in a perilous orbit around one another getting closer and closer. Black holes are incredible objects, they pull of their gravity - the amount they bend spacetime - is so strong that no light can escape them. No one knows what exists in the centre ofa black hole as normal physics completely breaks down. What we do know is that they are infinitely dense. One of these orbiting black holes was 29 times the mass of the Sun and the other was 36 times the mass of the Sun, but they were only about 200km wide. Which is tiny in comparison to the Sun which is over a million kilometres wide! And these black holes were orbiting each other really really fast, about the same frequency as the blade on a blender.

Imagine that, such massive objects rotating so quickly. These orbiting masses created ripples in the fabric of spacetime called gravitational waves, and the closer they orbited the bigger these waves got, until the black holes collided at half of the speed of light. And when they merged they formed a new blackhole that rang kind of like a bell, throwing out colossal amounts of energy as gravitational waves until it settled into a perfect sphere. And all of this happened in 0.2 seconds. And in the collision, they turned a huge amountof mass into gravitational wave energy. They lost a mass equal to three times the mass of the Sun which got turned in to gravitational wave energy by Einsteins equation E=mc^2. This created a huge wake of gravitational waves that ripped out in all directions at the speed of light. And, and this is the thing that gets us, over that last fifth of a second this collision released more than ten times more energy than total output of all of the stars in the entire rest of the Universe! It just completely boggles the mind! Meanwhile on Earth… At this exact time our planet was looking very different to what we see now. It was a barren wasteland, there was no grass or trees, in fact no plants or animals at all. Life at this stage had only come as far as microscopic multicellular creatures that lived in the sea.

And while the gravitational waves tore through space towards us all of the complex life on Earth evolved and grew: plants and animals developed, amphibians crawled on land, there was extinctions, reptiles and dinosaurs and mammals, more extinctions. Primates evolved into all of human civilization right up until Saturday 12th November 2015 when the scientists at LIGO turned it on to begin their initial tests. A mere two days later and just in time the gravitational waves flew past us and the first direct detection on Earth was made. And that sound bumping is actually what these waves sounded like. Even though gravitational-waves are ripples in spacetime and not ripples in the air, they vibrate at similar frequencies, so we canactually turn them into sound waves and listen to them … boop … It might not sound very impressive, but detection of gravitational waves means a huge amount for science. The results of this detection have already been profound. This is the very first time that black holes have been directly detected, in fact gravitational waves are the only way you can directly detect them!

It will hopefully be able to look at what makes stars go supernova, and might be able to probe the very nature of spacetime and see if it is made of things called cosmic strings. But the most exciting thing is that we don’tknow what it will find. This is one of the best parts of science,when you’ve got a new tool to peer into a realm of reality that you’ve never been able to access before. Who knows what you’ll find? May be you’ll discover things that help explain some of the great mysteries of the Universe, maybe we’ll find things that we can’t explain at all, and then we have to come up with new physics. In any case I find it super exciting and no one can’t wait to see more results. So there you go, those are the basics of gravitational wave astronomy.

Galaectic Collision

Milkyway 

Vs 

Andromeda

 Astronomers have used the Hubble Space Telescopeto forecast a future cosmic pile up: the titanic collision of the Milky Way and the Andromeda galaxy in about four billion years time. The Andromeda Galaxy, some 2.2 million light-years away, is the closest spiral galaxy to our home, the Milky Way. 

For around a century,astronomers have known it is moving towards us, but whether or not the two galaxies wouldactually collide, or simply fly past each other, remained unclear. Now, a team of astronomershas used the Hubble Space Telescope to shed light on this question, by looking at the motion stars in the Andromeda Galaxy. We wanted to figure out how Andromeda was moving through space. So in order to do that we measured the location of the Andromeda stars relative to the background galaxies.

 In 2002 they were in one place, and in 2010 they were in a slightly different place. And that allowed us to measure the motion over a period of eight years. The motion is actually incredibly subtle,and not obvious to the human eye, even when looking at Hubble's sharp images. However,sophisticated image analysis revealed tiny movements that the scientists were able to project into the future. Based on these findings, it is finally possibleto show what will happen to the Milky Way over the next eight billion years, as theg galaexies drift closer, then collide and gradually merge into a single, larger, elliptical galaxy with reedish stars. 

And might the Solar System should in fact survive this huge crash. The reason we think that our Solar System will not be much affected by this collision between the Milky Way and Andromeda is that galexies are mostly empty space. Even though our galaxy, as well as the Andromeda Galaxy, has a hundred billion stars in it, they are very far apart. So if two galaxies actually collide with each other, the stars basically pass right between each other and thecthe of two stars directly hitting each other is really, really small. So the likelihood that our Solar System will be directly impacted by another star, for example, in Andromeda as we collide with it is really, really small. Well, if life is still present on Earth when this happens, the changes in the sky will be quite spectacular. 

This collision will be very very slow because the time scales on the scales of galaxies in the Universe are very very long. So you have to think, millions of years but even then over these timescales over millionsof years, we will see big changes. If we wait a few billion years, Andromeda will be huge on the sky. It will be as big as our Milky Way because we'll be very close to it. And then later, when the galaxies merge, the merged remnant of the Milky Way Galaxy and Andromeda will look more like an elliptical galaxy and we'll be sitting right in it. So the view of the Milky Way on the nightsky will be completely gone and this band of light will be replaced by a more spheroidal distribution of light. And so, the Sun, born in the Milky Way almost 5 billion years ago will end its life in a new orbit, as part of a new galaxy. 

The New Space Race

 The New Space Race 

2020

Let’s talk about the new race for space. Countries and companies are competing to develop brand new space technology. Right now, engineers are designing space colonies. It’s time to go back to the moon. This time, to stay. France and the US have even launched their own space force. A space force  as the sixth branch of the armed forces. That’s a big statement. So in this race, who could win and what’s the big prize? And why should we care about what’s happening up there? Let’s take a second to realise how close the future actually is.

  Space tourism is taking off. Billionaire Richard Branson just made his commercial space airline publicly-traded company of its kind Virgin Galactic the first publicly-traded company of its kind. Our little company is going to be floating in space next year and today it's floating on the stock market. And earlier this year, he opened a spaceport in New Mexico where customers who’ve paid 250,000 dollars each will soon board space-planes to Earth’s sub-orbit. You’ve probably also heard of the billionaire Elon Musk and his company SpaceX. He’s unveiled detailed plans to start construction on Mars  in just 30 years time. We want to just keep improving rocket technology until there’s a city on Mars. Now I know it all sounds incredibly ambitious.  But big ideas can become very real, very quickly. It’s happened before, during the first space race. 

In the 1950s, the US and Soviet Union  were locked in a Cold War over political ideology. “President Truman signs a bill to spend   over 3 billion dollars to fight communism”.  Both sides started developing bigger and better rocket technology to use in a potential nuclear war and to keep each other in check. But they quickly took that fight to space. “Space travel became headline news with the announcement  that the United States plan to launch their first satellite by 1957”.  But the Soviets beat them to it by launching Sputnik a tiny satellite that Washington feared   could zip over the US and gather intelligence. Four years later, the Soviet Union made history again  by putting the first human in space.  But soon enough, US President John F. Kennedy raised the stakes. We choose to go to the moon in this decade and do the other things. Not because they are easy, but because they are hard. In 1969, NASA put the first humans on the moon. That’s one small step for man, one giant leap for mankind. As to who won that, I think it's pretty clear that the USA won that race.  But it wasn't just about national prestige in a simple flag-waving sense. That's why there was such an emphasis on the various scientific instruments that were flown with the Apollo missions. 

What followed that first space race were, in fact, many  decades of science-driven space exploration.  Countries even collaborated with each other’s space programs to send space stations, telescopes, probes   and satellites across our solar system. NASA stayed in the lead, partly because of its space shuttle.  But over time, governments around the world  started pouring less money into their space programs. Including the US.  Eventually, NASA retired the shuttle for good in 2011. And in the meantime, new space powers emerged. Countries like China and India, who have  been pouring millions of dollars into their space programs. China and India are basically trying to one up each other in terms of getting into record books, with China going to the far side of the moon and India trying to land rovers on other planets. Which show a country's technological  progress, which turns into geostrategic influence. 

But it’s private companies, and the pockets of billionaires who’ve really been heating up the race. SpaceX has built the world’s first reusable rocket. And the company has been working with NASA to transport cargo to the International Space Station. The airplane manufacturer Boeing and a company called Blue Origin owned by Amazon’s CEO Jeff Bezos, are also competing for contracts. So are dozens of other start-ups around the world, including  RocketLab in New Zealand and iSpace in Japan. And the idea is that if companies can profit, science does too. The big prize obviously for any private entity is to be profitable and make a  business. Space is very hard. It's very expensive for us. For example, it's  doing really important things that really benefit humanity in some ways and make a profit. And the rewards could potentially be enormous. NASA believes there are nearly 800,000 asteroids in our solar system which contain valuable metals like gold, iron and platinum. And just one of those asteroids, called 16 Psyche, is thought to have about 700 quintillion US dollars worth of valuable materials. There are also very real plans to mine the moon for water and Helium-3. Which could both potentially be transformed into rocket fuel. It allows us to resupply our missions to Mars and we can even refuel orbiting satellites of Earth. 

And, guess what? Laws have already been drafted in the US and Luxembourg   to allow companies to keep what they mine on the moon, Mars or anywhere else. Companies aren't going to invest their money if they think that whatever they are able to mine belongs to mankind. They want it to belong to them. And the United States passed a legislation which basically said, "Okay we're good with that". And there was some international criticism of “why does it belong to you? And that leads us to another prize in this race, which is power. Even after the Cold War, space exploration has in some ways been driven by the military.  Now, government officials, military officials are saying that they would like  to have weapons developed and deployed by 2023.

 SpaceCom will defend America’s vital interests in space the next war-fighting domain. But there are no actual weapons in space. Yet. There is an internationally agreed “Outer Space Treaty” to stop weapons of mass destruction from being used in space.  We have very few guidelines. There are no weapons of mass destruction to be placed in outer space, we are not to militarise the moon. But other than that, it's open territory.  Already, the US, Russia, China and India have carried out what they call “anti-satellite missile tests” by destroying old satellites in space. For now though, countries and companies say they are putting science first. And that’s a good thing because it’ll push the boundaries of human technology and could bring us  the answers to life’s big questions. And unlike the last space race, this time there seems to be more room for everyone. Hopefully that means everybody wins. 

Space Exploration

Humans in space

We always wanted to find out what's out there. We want to be able to, you know, expand out horizons and I think that that truly is built into the human spirit, we are always wondering "What's next?" "How much farther can we go?" - The Mercury astronauts when they get introduced they immediately callus as sort of a hero. The press conference that NASA had goes crazy and the astronauts becomeinstant celebrities. They sort a look like knights in armor, in some ways, going out there to defend the honor of The United States.

3...2...1...Lift off. - Roger, lift off and the clock has started. The feeling of that moment of exhilaration exhilaration because, of course, they'd been training for few years and in fact I was more than ready for the lift off to occur and was quite delighted inthe fact that it did occur. It occurred so smoothly. Capsules  turning around. Oh that tremendous view. - We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard. - It's outward bound.

People have a human feeling I think for wanting to go outward bound and it's in us. You know, to go, to see, to touch, to understand what's there. The ignition sequence start. It finally come ,  the day, the moment. The trajectory had been wrong. They had targeted into that in hospitable place. Then, they had to fly over this area at a high forward velocity. Then, pitch up to slow down, so it would kill that forward velocity and then start down like a helicopter. "That's one small step for man, one giant leap for mankind. ". The landing tome was a great celebration we had won the race, thenation was almost euphoric.  The knowledge that we gain about the origin and the evolution of the moon is one of these days, gonnahelp us right here on Earth. Course its only one area, but I believe it's an important area and I guess I'm bettin a lot on it.

NASA has been absolutely critical to improving the knowledgeof all human kind. Twelve humans walked onthe surface of the moon, which is a stunning achievement, and Americans are still the only country ever to have done that. We're going to go back to the moon and we're gonna take what we learned there and we're gonna go to mars. To get to Mars,it's about a six month journey. And as an operator, I would be really really happy if we could test out our operations and our equipment in our backyard. The moon's only three days away. The moon is the next step. So the Space Station is more than a million pounds, it's as big as two football fields. You are not going to bring that up in one single lift. So, we had to bring upthe Space Station in parts and assemble it. The Space Shuttle was instrumental into bringing up, at least the American side of that. It was more than forty missions over about thirteen years to assemble all of those parts of the Space Station.

And so human space flightis really interesting because we do adapt reallyquickly to the environment. How quickly, it feltnatural to float around. How quickly, it felt normal to look out the window and see the earth go by. - Human being are built to be able to adapt to weightlessness andthat allows us to go do that exploration and so we have improved the exercise equipment,we improved the diet, the vitamins. It mean we would come back so strong, that physically one will actually be stronger than when he left,
As the results show when the physical fitness test  is done when astronauts got back. It gives me great hope that, you know, if we have similar type of equipment on our long duration space vehicles, we're going to show up on Mars and be ready to work the minute we get there.

Orion, our state of the art space craft, is designed to take crews into deep space, and then once their work is done, safely bring them back home. Sometimes folks ask , you know, what do you think the next sixty years has in store? I don't know all of the destinations that we will visit, the mysteries we will solve, the places that we will leave footprints, again. - And we want to see what's out there, we want to see how it works, we want to go explore. There's always this desire to learn more, to satisfy that inquisitive nature. Let's go do it.

Astronomy vs Astrology

Astronomy 

Vs

Astronomy

The word Astronomy meaning "the study of stars" in initial stage but the words change meaning over time, and  it’s pretty well understood that astronomy is science, and astrology… isn’t. Millennia ago, astrology was as close to science as you got. It had some of the flavors of science: astrologers observed the skies, made predictions about how it would affect people, and then those people would provide evidence for it by swearing up and down it worked. The thing is, it really didn’t; the fault of astrology lies in ourselves and not our stars. People tend to remember the hits and forget the misses when predictions are made, which is why they sometimes sit in casino spumping nickels into machines that are in proven to be nothing more than a method for reducing the number of nickels you have. But astrology led to people to really study the sky, and find the patterns there, which led to a more rigorous understanding of how things worked in the heavenly vault. It wasn’t overnight, of course. This took centuries.

Before the invention of the telescope, keen observers built all sorts of odd and wonderful devices to measure the heavens, and in fact it was before the telescope was first turned to the sky that a huge revolution in astronomy took place. It is patently obvious that the ground you stand on is fixed, rooted if you will, and the skies turn above us. The sun rises, the sun sets. The moon rises and sets, the stars themselves wheel around the sky at night. Clearly, the Earth is motionless, and the sky is what is actually moving. In fact, if you think about it, geocentrism makes perfect sense that all the objects inthe sky revolve about the Earth, and are fixed to a series of nested spheres, some of which are transparent, maybe made of crystal, which spin once per day. The stars may just be holes in theotherwise opaque sphere, letting sunlight though. Sounds silly to you, doesn’t it? Well, here’s the thing: If you don’t have today’s modern understanding of how the cosmos works, this whole multiple-shells-of-things-in-the-sky thing actually does make sense. It explains a lot of what’s going on over your head, and if it was good enough for Plato, Aristotle, and Ptolemy, then by god it was good enough for you. And speaking of which, it was endorsed by the major religions of the time, so may be it’s better if you just nod and agree and don’t think about it too hard.

But a few centuries ago things changed. Although he wasn’t the first, the Polish mathematician and astronomer Copernicus came up with the idea that the sun was the center of the solar system, not the Earth. His ideas had problems,which we’ll get to in a later episode, but it did an incrementally better job than geocentrism. And then along came Tycho Brahe and Johannes Kepler, who modified that system, making it even better. Then Isaac Newton - oh, Newton- he invented calculus partly to help him understand the way objects moved in space. Over time, our math got better, our physics got better, and our understanding grew. Applied math was a revolution in astronomy, and then the use of telescopes was another. Galileo didn’t invent the telescope, by the way, but made them better; Newton inventeda new kind that was even better than that, and we’ve run with the idea from there.

Then, about a century or so ago, came another revolution: photography. We could capture much fainter objects on glass plates sprayedwith light-sensitive chemicals, which revealed stars otherwise invisible to us, details in galaxies,beautiful clouds of gas and dust in space. And then in the latter half of the last century, digital detectors were invented, which were even more sensitive than film. We could use computers to directly analyze observations, and our knowledge leaped again. When thesewere coupled with telescopes sent in orbit around the Earth - where our roiling and boiling atmosphere doesn’t blur out observations - we began yet another revolution. And where are we now? We’ve come such a long way! What questionscan we routinely ask that our ancestors would not have dared, what statements made witha pretty good degree of certainty?

Think on this: The lights in the sky are stars! There are other worlds. We take the idea of looking for life on alien planets seriously, and spend billions of dollars doing it. Our galaxy is one of a hundred billion others. We can only directly see 4% of the Universe. Stars explode, and when they do they createthe stuff of life: the iron in our blood, the calcium in our bones, the phosphorus that is the backbone of our DNA. The most common kind of star in the Universe is so faint you can’t see it without a telescope. Our solar system is filled to overflowing with worlds more bizarre than we could have dreamed. Nature has more imagination than we do. It comes up with some nutty stuff. We’re clever too, we big-brained apes. We’ve learneda lot… but there’s still a long way to go. So, with that, I think we’re ready.

Let’sexplore the universe. Astronomers aren’t just people who operate telescopes, but include mathematicians, engineers, technicians, programmers, and even artists. They also wrapped up with a quick history of the origins and development of astronomy, from ancient observers to the Hubble SpaceTelescope.

Astronomy

Astronomy

The Science of Stars

Talking of science. What is science? There are lots of definitions of science,but I’ll say that it’s a body of knowledge, and a method of how we learned that knowledge. Science tells us that stuff we know may not be perfectly known; it may be partly or entirely wrong. We need to watch the Universe, see how it behaves, make guesses about why it’s doing what it’s doing, and then try to thinkof ways to support or disprove those ideas. That last part is important. Science must be, above all else, honestly if we really want to get to the bottom of things. Understanding that our understanding might be wrong is essential, and trying to figure out the ways we may be mistaken is the only way that science can help us find our way to the truth, or at least the nearest approximationto it. Science learns. We meander a bit as we use it, but in the long run we get ever closer to understanding reality, and that is the strength of science. And it’s all around us!

Whether you know it or not, you’re soaking in science. You’re a primate. You have mass. Mitochondria in your cells are generating energy. Presumably,you’re breathing oxygen. But astronomy is different. It’s still science, ofcourse, but astronomy puts you in your place. Because of astronomy, I know we’re standing on a sphere of mostly molten rock and metal 13,000 kilometers across, with a fuzzy atmosphere about 100 km high, surrounded by a magnetic field that protects us from the onslaught of subatomic particles from the Sun 150 million km away, which is also flooding space withlight that reaches across space, to illuminate the planets, asteroids, dust, and comets,racing out past the Kuiper Belt, through the Oort Cloud, into interstellar space, pastthe nearest stars, which orbit along with gas clouds and dust lanes in a gigantic spiralgalaxy we call the Milky Way that has a supermassive black hole in its center, and is surroundedby 150 globular clusters and a halo of dark matter and dwarf galaxies, some of which it’seating, all of which can be seen by other galaxies in our Local Group like Andromedaand Triangulum, and our group is on the outskirts of the Virgo galaxy cluster, which is partof the Virgo supercluster, which is just one of many other gigantic structures that stretchmost of the way across the visible Universe, which is 90-billion light years across andexpanding every day, even faster today than yesterday due to mysterious dark energy, andeven all that might be part of an infinitely larger multiverse that extends forever bothin time and space.

See? Astronomy puts you in your place. But what exactly is astronomy? This isn’tnecessarily an obvious thing to ask. When I was a kid, it was easy: Astronomy is thestudy of things in the sky. The sun, moon, stars, galaxies, and stuff like that. Butit’s not so easy to pigeonhole these days. Take, for example, Mars. When I haul my ‘scopeout to the end of my driveway and look at Mars, that’s astronomy, right? Of course!But what about the rovers there? Those machines aren’t doing astronomy, surely. They’re doing chemistry, geology, hydrology, petrology… everything but astronomy! So nowadays, what’s astronomy? I’d say it’s still studying stuff in the sky, but it’s branched out quite a bit from there.Borders between it and other fields of science are fuzzy. Humans might like firm, delineated boundaries between things,but nature isn’t so picky.

Astronomers

Who are we? What do we do? I used to look through telescopes for a living,or at least study the data that came from detectors strapped onto them. But now they talk and write (and make videos) about astronomy, and relegate my viewing to their personal backyard telescope. But they still consider themself an astronomer, so that should give you an idea that there’s a lot of wiggle room in the profession. Doing the observations fit the physicalmodel of how stars blow up, or how galaxies form, or the way gas flows through space?Well, one better know the maths and physics, because that’s how we test the hypotheses. And someone who does that is generally called an astrophysicist.

Of course, the telescopes and detectors don’t create themselves. We need engineers to design and build them and technicians touse them. Most astronomers don’t actually use thetelescopes themselves anymore; someone who’s trained in their specific use does that forthem. Some of those instruments go into space, andsome go to other worlds, like the moon and Mars. We need astronomers and engineers andsoftware programmers who can build those, too. And then, at the end of all this, we need people to tell you all about it. Teachers, professors, writers, video makers, even artists. So they'll tell you what: If you have an interestin the Universe, if you love to look up at the stars, if you crave to understand what’s going on literally over your head, then who am I to say you’re not an astronomer?

However you define astronomy, humans have been looking up at the sky for as long as we’ve been humans. Certainly ancient people noticed the big glowy ball in the sky, and how it lit everything up while it was up, and how it got dark when it was gone. The other, fainter glowy thing tried, but wasn’t quite as good as lighting up the night. They probably took that sort of thing pretty seriously. They probably also noticed that when certain stars appeared in the sky, the weather started getting warmer and the days longer, and when other starswere seen, the weather would get colder and daytime shorten.

And when humans settled down, discovered agriculture,and started farming, noticing those patterns in the sky would have had an even greater impact. It told them when to plant seeds, and when to harvest. The cycles in the sky became pretty important. So important that it wasn’t hard to imagine gods up there, looking down on us weak andridiculous humans, interfering with our lives. Surely if the stars tell us when to plant,and control the weather, seasons, and the length of the day, they control our lives too… and astrology was born. Astrology literally means “study of the stars”; as a word it’s been used before science became a formal method of studying nature. It irks a bit, since it got the good name, and now we’re stuck with “astronomy,”which means “law or culture of the stars." That’s not really what it is!

Solar Eclipse 2020

Annular Solar Eclipse!

2020

A solar eclipse occurs when a portion of the Earth is engulfed in a shadow cast by the Moon which fully or partially blocks sunlight. This occurs when the Sun, Moon and Earth are aligned in a straight line. Such alignment coincides with a new moon indicating the Moon is closest to the ecliptic plane. In a total eclipse, the disk of the Sun is fully covered by the Moon. In partial and annular eclipses, only part of the Sun is obscured.

An annular solar eclipse – now often called a ring of fire eclipse – caught by Geoff Sims on May 10, 2013. Like a total solar eclipse, an annular solar eclipse happens when the new moon moves directly in front of the sun. During a total solar eclipse, the new moon completely covers over the solar disk.

The annular solar eclipse will see the Sun, Moon and Earth align on Sunday, 21 June, creating a spectacular effect for sky gazers to witness across large parts of the world.

The annular eclipse will first start for the people of Congo in Africa and progress through South Sudan, Ethiopia, Yemen, Oman, Saudi Arabia, the Indian Ocean and Pakistan, before entering India over Rajasthan. It will then move on to Tibet, China, Taiwan, before ending at the middle of the Pacific Ocean.

The Moon will be at its furthest stage of its orbit around the Earth, known as its apogee, meaning it'll appear slightly smaller in the sky. This means it'll not able to completely block out the Sun, thus creating the "Ring of Fire ".

⚠️Precautions⚠️

✔️ Do not look at the eclipse with naked eyes as it can cause serious eye damage

✔️ Never look at the sun through unfiltered telescope, binoculars, cameras or other optical devices

✔️ Use protective eye gear/solar viewing glasses/eclipse glasses; If you normally wear eyeglasses, keep them on & wear the eclipse glasses over them