Putting the speed of light into perspective

Posted on January 23, 2018 by terranojm

The theory of special relativity tells us that there is an absolute speed limit in the universe, that being the speed of light. At a speed of about 300,000 km/s, light takes only one second to travel to the Moon from Earth and eight minutes to travel to the Sun from Earth. This speed is extremely fast for human standards. For instance, in 2016, NASA’s Juno spacecraft arrived at Jupiter, accelerating to a speed of about 265,000 km/h. This made it the fastest human-made object in history. Still, this speed of 265,000 km/h is nowhere close to light’s speed of 300,000 km/s.

However, not even light seems fast in the context of just how massive our universe is. For example, it takes light four years to reach Earth from Alpha Centauri, the star system nearest to us besides the Sun. It takes light 6,000 years to reach us from the Crab Nebula, the remnant of a massive star in the direction of Taurus. It takes light 2 million years to reach us from the Andromeda Galaxy, the nearest galaxy to our own. It takes light 650 million years to reach us from the Hercules Cluster of galaxies. Keep in mind, the universe’s expansion started approximately 14 billion years ago, so there are even farther objects that light would take even longer to travel to Earth from!

Given these facts, convenient interstellar space travel seems like an impossible feat. The fastest object humankind has managed to create couldn’t even travel in an hour the distance that light travels in a second. And our spacecrafts that humans can actually travel on are even slower! So if we can’t travel faster than light, and light takes at least millions of years to reach nearby galaxies, then traveling through the universe like we’re in Star Trek seems hopeless!

Nevertheless, it is important to point out that special relativity involves local laws of physics. We may not be launching rockets faster than the speed of light, but general relativity tells us that these rules do not apply for galaxies at the far side of the universe. So does that mean a speed faster than the speed of light exists in the universe? In fact, the universe expands faster than the speed of light. The observable universe is only some fraction of the entire universe. Additionally, we know that the early universe underwent a phase of rapid, exponential expansion, and more distant objects move faster away from us than less distant objects.

Therefore, it makes sense that there would have been points during the entire universe’s expansion in which objects were moving away from other objects faster than the speed of light relative to each other or that the very distant objects at the outermost parts of the universe that are moving away faster and faster away from us will eventually exceed the speed of light if they have not already. As for the question of whether or not humans will find a way to exceed the speed of light, we may have to simply hope that we will someday find a way to use wormholes to transport to other worlds!

timespace

Universe Expansion (from Scienceline)

 

 

Links:

http://curious.astro.cornell.edu/physics/104-the-universe/cosmology-and-the-big-bang/expansion-of-the-universe/616-is-the-universe-expanding-faster-than-the-speed-of-light-intermediate

https://www.quora.com/Which-is-faster-Universe-expansion-or-speed-of-light

https://www.space.com/33306-how-does-the-universe-expand-faster-than-light.html

http://www.physicsoftheuniverse.com/topics_relativity_light.html

https://www.livescience.com/32655-whats-the-fastest-spacecraft-ever.html

http://casswww.ucsd.edu/archive/public/tutorial/Intro.html

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Progression of the Seasons? Thank Precession

Posted on January 23, 2018 by jonahastroblog

Everyone knows that the Earth experiences seasons. In the Northern Hemisphere children rejoice as they enjoy the summer sun in the month of June, while in the Southern Hemisphere they embrace the cold, daydreaming of warm summer days that await them in six months. However, what if I were to tell you that in about 13,000 years Gemini’s will be born in the winter (in the Northern Hemisphere) and Aquarius’s will be born in the summer (in the Northern Hemisphere)?

Indeed, this is a phenomenon known as “Precession”.

 

precession
Sourced from gramhancock.com

Precession is a phenomenon in which Earth’s axis rotates in a circular pattern. This effect is actually caused by Earth’s rotation. See, if you go back to classical physics (which I know are skeletons in the closet), we know that something accelerates in a circular motion there is an equal and opposite reaction that occurs, or a centrifugal force. This centrifugal force fights the force of gravity, which is the force that keeps the Earth from splitting apart on itself while it rotates. If you’ve ever been in a car and made a turn, or you’ve been on a merry-go-round you’ve probably experienced a force that is trying to push you out of the car or off of the merry-go-round. This is centrifugal force.

 

circular_motion_car
The centrifugal force pushes against the force of gravity and causes the Earth to bulge, causing the shape of the Earth to be more bulged at the equator than at its poles. Sourced from ScienceLibrary

It is this centrifugal force that causes the Earth to bulge at the equator than at its poles. This bulging makes it so that Earth is not a perfect sphere. Now, since Earth is not a perfect sphere the sun will pull more on the bulge of the Earth that is closer to it than the other end of the bulge. This imbalance of force causes the Earth to rotate, with its axis as its center point. This rotation, as noted in the figure above, takes about 25,700 years to make a full 360 degree rotation. Now, what does this mean in terms of seasons?

Well, if we look at the first picture we can see that after approximately 13,000 years the Earth’s axis will be tilted the other way, or -23.5 degrees. This means that if we view things using our calendar then it will be winter in the northern hemisphere in the month of June and summer during Christmas! However, according to Cornell University Professor Jagadheep Pandian, humans will adjust the calendar so that it is always summer in June and always winter in Decemeber (sourced from Cornell University). I guess we will always have a white Christmas!

If you would like to see a video description of what I just described, I highly recommend watching this video by It’s Just Astronomical.

Always remember, look up, be curious, and be awed.

(Featured image sourced from epiphanies.com.au)

 

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Oumuamua – space rock or spaceship?

Posted on January 23, 2018 by justinrstevens
Comet_20171025-16_gif
animation of Oumuamua’s trajectory (Wikipedia)

Some scientists called it an asteroid.  Others theorized that it was an alien spacecraft.  Still others cast it off as a mere “space cucumber.”

This mysterious space rock known as Oumuamua (Hawaiian for “first messenger”) has captivated scientists since its discovery in mid-October of 2017.  Oumuamua was discovered in Hawaii, hence its awesome name. This object is the first observed visitor to our solar system from the outside (from another star system).  Unfortunately, Oumuamua was only detected on its way out of our Solar System, after using the Sun as a sort of “gravity slingshot.”  Fascinatingly, this object was not vaporized after passing extremely close to the Sun.  Instead, many scientists believe that this was prevented by a thick layer of carbonic dust that encases the object.

Oumuamua’s interesting shape posed more tantalizing questions.  Over eight times longer than it is tall/wide, Oumuamua certainly does not conform to the typically roundish (a serious oversimplification here) of most asteroids.  This led many to believe that the mysterious object, like the eerily-similar “Rama” from the Arthur C. Clarke sci-fi novel Rendezvous with Rama (1973), is actually an alien spaceship. **SPOILER ALERT** In the novel, a strange oblong “asteroid” turns out to be a transport vessel from an advanced alien civilization.  This spaceship (named “Rama”) uses our Sun to pick up speed while changing the course of its interstellar journey.

However, Oumuamua does not appear to be a real-life Rama.  For starters, its spin does not mimick that of a spaceship attempting to generate artificial gravity.  Rama, for example, spins like a football and thus generates artificial gravity via centrifugal force.  Oumuamua, on the other hand, flips end-over-end in a somewhat chaotic fashion.  A few scientists have concluded that Oumuamua’s motion is almost certainly incapable of simulating gravity.

Moreover, a team at the Green Bank Radio telescope fixed its attention towards Oumuamua in hope of detecting an alien radio transmission, but to no avail.  In the disappointing words of one astronomer Alan Fitzsimmons, Oumuamua is probably nothing more than a “space cucumber.”  At least to the best of our knowledge…

Thanks for reading!

-Justin

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The Amazing Cosmic Calendar

Posted on January 23, 2018 by kathrynkellner

 

Cosmic_Calendar.png
Wikipedia’s Version of the Cosmic Calendar

Recently in our reading, we learned about the cosmic calendar (pictured above) – a cool concept I’d like to share a little bit about on my blog. The cosmic calendar is the idea of what it would look like if we took the entire existence of the universe, all fourteen billion years, and compressed it into one standard year of 12 months, with each month equaling a little more than 1 billion years. In many ways, it is a powerful concept because it shows you just how insignificant human existence is in the grand scheme of the universe, which is something that has always fascinated me. For instance – January 1st would be the Big Bang, with the Milky Way forming sometime in the month of February, and then it isn’t until September, 7 months (or around 8 billion years later) that Earth formed, and then early life, not even humanity, appeared in late September. The most amazing part, I think, about the cosmic calendar, is that it isn’t until December 31st that humans, as we know them, began to appear. Not to mention that, on the cosmic calendar, all of our majorly significant history – our ancient cities and powers and actions that people devote so much importance to – only occurred in the last 30 seconds of December 31st. This is such an eye-opening idea because again it highlights what astronomers have been trying to tell us from the beginning: in the scope of the universe, we are not as significant as we seem to think. Just like much of what we’ve learned about, the cosmic calendar is another aspect of astronomy that is very humbling.

Source: The Cosmic Perspective: The Solar System 8th Edition

 

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Moon Myths

Posted on January 23, 2018 by lexisastronomyblog

No other celestial body has quite the same reputation as our moon. The source of myths, legends, and ghost stories, the Moon is a symbol of superstition and wonder. We know that the Moon causes the rising and falling of the ocean tides, but could this mysterious master of the tides control something other than Earth’s water? Urban legend and folklore has spurred on the idea that the Moon has real, and sometimes strange, effects on human behavior. After all, the word “lunacy” is derived from the Roman goddess of the moon, Luna. Legend states that car accidents, heart attacks, violent episodes, and suicides increase in occurrence during a full moon. During the 1800s, London’s psychiatric hospitals would shackle their patients during a full moon, and the city made sure to have more police officers than normal on duty. Even now, the phrase “there must be a full moon tonight” is used commonly when strange behavior is taking place. However, despite’s the Moon’s mystical reputation, there is no real evidence that the moon has any effects on human behavior.

16209774551_78eeb72892
Full Moon via Flickr

Before modern science and technology, many believed that the Moon’s control of the tides also meant that the Moon’s gravity affected the water in our bodies. Greek philosopher Aristotle called the brain the “moistest” organ, concluding that it was susceptible to the gravitational pull of the Moon. Now though, science proves that the Moon is too far away to have any dramatic effect on human bodies. Multiple studies have been conducted trying to prove the claims about the Moon’s effects, but each one has failed to show any correlation.

The root of our modern superstitions about the Moon seem to come from the fact that in ancient times when there was no electricity, the brightness of the full moon caused people to be unable to sleep, leading to sleep deprivation. Sleep deprivation can cause people to behave strangely and sometimes violently, which are the behaviors that are attributed to the Moon’s influence. I also have an idea that when ancient peoples could not find a physical cause for strange behaviors, they would simply blame the stars. From mythology to astrology, the celestial bodies always seem to be the ones at fault for strange occurrences down below. However, despite the facts and science, the Moon will always be seen as our mysterious, illusive ruler of the night sky.

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Blog #1 – Moon Myths

Posted on January 23, 2018 by lexisastronomyblog

No other celestial body has quite the same reputation as our moon. The source of myths, legends, and ghost stories, the Moon is a symbol of superstition and wonder. We know that the Moon causes the rising and falling of the ocean tides, but could this mysterious master of the tides control something other than Earth’s water? Urban legend and folklore has spurred on the idea that the Moon has real, and sometimes strange, effects on human behavior. After all, the word “lunacy” is derived from the Roman goddess of the moon, Luna. Legend states that car accidents, heart attacks, violent episodes, and suicides increase in occurrence during a full moon. During the 1800s, London’s psychiatric hospitals would shackle their patients during a full moon, and the city made sure to have more police officers than normal on duty. Even now, the phrase “there must be a full moon tonight” is used commonly when strange behavior is taking place. However, despite’s the Moon’s mystical reputation, there is no real evidence that the moon has any effects on human behavior.

16209774551_78eeb72892
Full Moon via Flickr

Before modern science and technology, many believed that the Moon’s control of the tides also meant that the Moon’s gravity affected the water in our bodies. Greek philosopher Aristotle called the brain the “moistest” organ, concluding that it was susceptible to the gravitational pull of the Moon. Now though, science proves that the Moon is too far away to have any dramatic effect on human bodies. Multiple studies have been conducted trying to prove the claims about the Moon’s effects, but each one has failed to show any correlation.The root of our modern superstitions about the Moon seem to come from the fact that in ancient times when there was no electricity, the brightness of the full moon caused people to be unable to sleep, leading to sleep deprivation. Sleep deprivation can cause people to behave strangely and sometimes violently, which are the behaviors that are attributed to the Moon’s influence. I also have an idea that when ancient peoples could not find a physical cause for strange behaviors, they would simply blame the stars. From mythology to astrology, the celestial bodies always seem to be the ones at fault for strange occurrences down below. However, despite the facts and science, the Moon will always be seen as our mysterious, illusive ruler of the night sky.

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The Vast Size of the Universe

Posted on January 22, 2018 by adventuresinspace

Image result for the vast size of the universeby BBC Earth Website 

Looking up at the sky from Earth, the universe seems like it can fit in the palm of your hand. In previous years, before we truly had an understanding of how big and old the universe was, we believed that Earth was at the center of the universe and all the other stars revolved around us. Now, because of the advancement of technology, we have a more accurate description of our cosmic address. It goes like this:

Nashville – Tennessee- The United States – North America – Earth- Solar System – Orion Spur – Local Group – Vergo Supercluster – Lanikea Supercluster – Universe

To the glass half-empty individual, it may seem like we are insignificant when compared to the size of the universe. To the glass half-full individual, the maintenance of Earth is of great importance in order to continue the existence of the human race.

The universe is around 13.8 billion years old and has been expanding ever since, whereas Earth is approximately 4.5 billion years old. Every day, the universe continues to expand and grow in size. Majority of the largeness of the Universe is space. Even with the advanced technology we have today, we can only see the observable universe, meaning there is still much of it that remains unseen.

What is your perspective? Are we a race of insignificance when compared to the size of the universe or is our role as keepers of Earth of vital impact on the Universe?

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The Cosmic Calendar and the Cosmic Perspective

Posted on January 22, 2018 by stellarastronomy1995

Shrinking the history of the Universe down to fit into the time frame of one Earth year may not seem all too impressive at first. The realization however that, fit into a calendar year, each month is representative of about one billion years, while each day is 40 million years, presents one with the inescapable feeling of awe that accompanies the Cosmic Perspective.

The calendar begins on January 1st, signifying the birth of the Universe: the Big Bang, and ends at the present moment on December 31st at midnight. Between these two points of time is the aggregate of all that has unfolded from our point of view in the observable universe. And it is immense.

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The Cosmic Calendar

 

A clip of Dr. Neil deGrasse Tyson explaining the Cosmic Calendar illustrated above in the show Cosmos can be found at this link: https://youtu.be/ShTxGumvbno

One valuable perspective gained from recognizing the history traced through the Cosmic Calendar is that we humans and our entire worldview are seemingly one of the afterthoughts of the Universe. Multicellular life does not evolve on Earth until December on the Cosmic Calendar. Even further, recorded history takes place within the last minute on December 31st before the clock strikes midnight. The better part of the entire year at a glance? We humans were not anywhere near existence. What wonders could have come and gone prior to our actualization? Will the existence of our species be only a blip in time on the Cosmic Calendar of the future, or will we endure long enough, and prosper amongst the stars, entrenching ourselves as a species that will occupy more than a minute of time on the Calendar?

 

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Solar Eclipse: When and Why

Posted on January 22, 2018 by haleytopper04

In honor of the solar eclipse that happened in late august, I thought I’d talk about the phenomenon. A solar eclipse happens when the moon gets between the earth and the sun, and the moon casts a shadow. It should be known that the fact that solar eclipses can happen at all is a total coincidence. The moon is about 400 times smaller than the sun, however the sun is about 400 times farther away than the moon, so the two appear to have the same size in our sky.

It can be a common misconception that every time the moon gets between our sun and earth, we have a solar eclipse. This, however, is not true. The moon orbits with a tilt of about 5 degrees, so an eclipse only happens when everything lines up perfectly. In August, we experienced a total solar eclipse. During a total solar eclipse, the moon casts its shadow on earth’s surface and, in the path of totality, you will see only the corona and it will seem as though it is night time. The next solar eclipse is a partial eclipse (only a partial shadow will be cast on the surface) is on February 15th and can be seen from Antarctica, the Atlantic Ocean, and Southern South America!

Source: https://www.space.com/15584-solar-eclipses.html

the-total-solar-eclipse-has-10-distinct-phases--heres-what-they-look-like.jpg
Business Insider
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The Last 2 Minutes of History

Posted on January 22, 2018 by laurenegish

https://www.scienceabc.com/nature/universe/cosmic-calendar-universe-365-big-bang-compress-history.html
Important Events in the Cosmic Calendar

Down on Earth, it’s easy to think the passage of 100 years is a long time. After all, it’s certainly longer than a human’s life expectancy. However, after hearing that modern humans can only be accounted for in 2 minutes of history, it’s hard to believe that the time spanning from the origins of modern humans until today has occupied a significant amount of time. Now you may wonder why I said that modern humans in history only lasts for 2 minutes when modern humans evolved around 40,000 years ago. Let me explain. If the universe’s history, starting with its inception 14 billion years ago, was put into a calendar of one year, modern human history would only account for two minutes of the time. That means that if you placed all 14 billion years of the universe’s history into a calendar year, modern humans would occupy the calendar at 11:58 on December 31. This calendar, known as the cosmic calendar, begins on January 1st, when the Big Bang occurs. According to this calendar, the Milky Way was formed sometime in February. What is even more fascinating about this cosmic calendar is that when calculated to the scale of a year, dinosaurs roamed the Earth only five days prior to modern humans, on December 26. This is a stark contrast to our record of time, where dinosaurs populated the planet around 225 million years ago. Probably the most important idea that this calendar puts into perspective is the fact that our solar system, despite the fact that it is 4.6 billion years old, has only been a part of the universe for a third of the universe’s existence. That means that according to the cosmic calendar, our solar system only formed on September 3. When put into perspective, it’s hard to believe that any passage of time is truly significant over the span of 14 billion years and when this is compounded with the vast size of the universe, it’s hard to believe that our lives are not anything more than a blip in space and time.

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