The Scope of the Universe

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astro201, blog10, class, size, universe, voyager

Although we talked about the scale of the Sun, the galaxy, and the rest of the universe, it didn’t really hit me until the end of the semester just how gigantic the scale is. Sure, it helped to learn that if the Sun were the size of a basketball, the Earth would be about as big as a pea. If the universe was shrunk so that the Sun was the size of a melon and located in California, the next closest star would be located in Washington, D.C. If we think about the size of the universe itself, it’s hard to even comprehend the possible distances. It would take 14 billion years, travelling at the speed of light, to cross the observable universe. And we don’t even know what, if anything, lies beyond that.

Despite all of these scales and comparisons, I did not understand the size of the universe until we talked about Voyager 1 and the Pale Blue Dot. It has taken a spacecraft launched by humans nearly forty years to reach the outer parts of our solar system, but it would still take it a few hundred even reach the Oort Cloud. We can hope that the information sent by our small, insignificant blue dot will be found by other intelligent beings, but the universe is just too big for us to know what is out there.

It can be easy to feel small and insignificant when one considers the size of the entire universe, but the fact that all of us are composed of material created in the explosions of stars is also empowering. If the universe has the power to create a group of organisms like humans, who have the power to function so intellectually and so curiously, there must be much more out there for us to discover. We simply have to continue to innovate and to explore.

The Pale Blue Dot, a photograph of Earth captured by Voyager 1 at a distance of 40 AU from Earth (Voice Chronicle)

Sending Chuck Berry to Space

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aliens, astro201, astrobiology, blog9, communications, golden record, life, voyager

In 1977, NASA launched the spacecraft Voyager 1 into space to observe Jupiter and Saturn and, eventually, to travel outside our own solar system to explore interstellar space. The probe is still traveling and, though it will take a few hundred more years for it to even reach the Oort Cloud, it is the farthest-traveling probe that humans have ever sent into space. It is currently about 11 billion miles away.

Because it has traveled so far, we really don’t know what – or who – it could encounter. Humans have not detected any sign of extraterrestrial life emitting signals or attempting to communicate with beings like us (see more on theories of life and Fermi’s paradox here). However, in the case that Voyager 1 does meet aliens in its journey out of the solar system, the spacecraft is prepared.

The current location of Voyager 1, mapped by NASA Jet Propulsion Laboratory

The small probe is equipped with a record player and a record made of gold that could be played by other creatures that would happen to find the probe. Scientists say that if creatures were able to locate it, they would have the intellectual and technological capability to work it. The golden record is likely still in good condition, as it is sealed in an aluminum sheath and preserved in an airtight vacuum. (NASA JPL)

The record contains a wide variety of sounds from Earth – including whale sounds, other natural sounds, the crying of a baby, and the sound of a car – as well as greetings in fifty-five different languages, a peaceful salutation from the Secretary General of the U.N., and a message from American President Carter. Also included on the record was music from several areas of the globe representing many ethnic backgrounds, including American singer Chuck Berry. There is even information encoded on the record itself; it is inscribed with a model of how to play the record and a diagram of our understanding of the Solar System. (The Atlantic)

Though Voyager 1 may soon fall outside the range of interacting with NASA, it will continue to travel through space. We can only wonder if other creatures will find the record and the rest of the probe, but the possibility of communicating with other beings in the universe is nothing less than intriguing.

More about Voyager 1 here

The Toughest Creature in the World

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astro201, blog8, extremophile, life, tardigrade, water bear

In the early 1700s, several different scientists examining the components of water and water habitats came across a miniscule creature that seemed to float around in many different areas abundant with water. These scientists found that these creatures were really present in many dry places too, but only began to move when hydrated by rainfall or submersion in some body of water.

These creatures were later named tardigrades, and they would become some of the most mysterious and fascinating subjects in modern biology and, though perhaps this may seem unlikely, astronomy. Tardigrades are also called “water bears” because they resemble small, squishy bears with claws and sharp, pointy teeth. In general, most tardigrades survive by sucking up juices from moss, lichens, and algae.

The tardigrade, also called a water bear (NASA Astronomy Picture of the Day).

Though found in some common areas, tardigrades have also been found at elevations of more than 18,000 feet in the Himalayan Mountains, in Japanese hot springs, on the floor of the ocean, and within layers of ice in Antarctica. Tardigrades are an example of “extremophiles,” organism that can survive in extreme environments like these. Our current understanding of tardigrades supports the theory that in order to survive in areas of such extreme pressure and temperature, tardigrades enter a death-like state in these conditions, lowering their metabolism hundreds of times and shedding all water from their bodies. When they are returned to a stable environment, they become rehydrated and continue to live, eat, and reproduce (BBC).

It seemed that these small organisms could survive nearly any climate change in any environment. So, naturally, scientists pushed them further to see if they could survive in the most formidable environment known to mankind – outer space. In 2007, Swedish astronomers launched a satellite into space covered in tardigrades that would, upon leaving Earth’s atmosphere, be freely exposed to the vacuum of space and intense UV radiation from the Sun. The satellite stayed in space for ten days and then returned to Earth. Though many of the tardigrades had gone into a dried-out state, the vast majority of them were revived upon entering water on Earth. A few of them even laid healthy eggs even after being exposed to such a harsh environment.

This experiment could completely change the way that we think about life in space. In fact, many astronomers are exploring the Panspermia Hypothesis, which theorizes whether organisms like tardigrades would be able to survive if a giant impactor – an asteroid, for instance – hit Earth. If tardigrades were able to survive on pieces of Earth that were ejected into space, the existence of life could be spread throughout the Solar System and, potentially, throughout the universe (Smithsonian).

Many aspects of tardigrades are still a mystery to humans. Why did they evolve to be able to withstand several times the amount of temperature and pressure found anywhere on Earth? Where did they evolve, and have they really endured on Earth since the Cambrian period? What can they tell us about the existence of life in space?

Watch this goofy video for more about tardigrades!

More info at New Scientist.

New Horizons

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astro201, blog7, exploration, NASA, new horizons, pluto, sensors

Exploring Pluto

Pluto, the small icy body at the edge of our planetary system, has been under scrutiny in scientific and public communities for the last decade after the International Astronomical Union (IAU) demoted it from a true planet to a dwarf planet. Though Pluto’s planetary status is important, the real issue raised by this demotion was that of the IAU’s lack of a true classification system for planets and dwarf planets. One of the best ways to refine this definition is it to explore the composition, features, and satellites of Pluto in order to determine the differences between it and terrestrial and Jovian worlds.

A graphic of New Horizons from BetaWired.

NASA’s Response to the Need for Exploration

Following the discovery of two faraway satellites of Pluto in 2005, NASA collaborated with the Southwest Research Institute (SwRI) to launch the space probe New Horizons. This probe was built to fly by the terrestrial planets, approach Jupiter for a gravitational assist that would slingshot it to the outer reaches of our Solar System, and get closer to Pluto and its moon Charon that any space probe has gone thus far. The first close flyby of Pluto is planned for July 2015. New Horizons may then fly past Pluto and into the rest of the Kuiper Belt, sending back images of the compositions of various Kuiper Belt objects. (Johns Hopkins University)

The Spacecraft

New Horizons is equipped with seven different probes to measure various aspects of Pluto and its moons. The first is an ultraviolet imaging spectrometer that will measure the composition of Pluto’s atmosphere. Other sensors will measure the geography and surface features of Pluto and other worlds; measure the density, pressure, and temperature of atmospheres; read evidence of geological features like volcanoes and geysers on planets and moons; study solar wind and flow of electrons around planets; analyze the movement of particles leaving Pluto’s atmosphere; and examine dust particles in the space around planets. (See NASA for more info.)

All in all, New Horizons aims to give astronomers a better understanding of the composition and current layout of large bodies in the outer reaches of our Solar System. This will help us understand the differences between terrestrial planets, Jovian planets, dwarf planets, and Kuiper Belt objects, and may help us understand more about the formation of the outer Solar System.

See here for info about naming the features of Pluto!

An Ocean on a Moon?

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astro201, blog6, ganymede, jupiter, magnetosphere, moon, ocean, solar system

One of the largest satellites in the solar system is Jupiter’s moon Ganymede. Though Ganymede is classified as a moon because it orbits a planet, it actually shares more features with the Earth than with our Moon. Ganymede is nearly as large as Mars and dwarfs Mercury and Pluto in terms of radius. Astronomers think that Ganymede’s surface is part of a thick layer of ice, but it also has a layer of rock beneath this ice – a more solid version of Earth’s mantle – and an inner core made of metal that gives Ganymede a magnetosphere. Though there is a very thin atmosphere, scientists have found evidence of oxygen on the surface of the planet.

Jupiter’s largest moon, Ganymede (Nasa Solar System Exploration)

Since the Hubble Space Telescope has been transmitting images of Ganymede’s surface, astronomers have established growing confidence that there may be a liquid ocean of salt water beneath the icy surface of the planet. An ocean like this would minimize the effects of Jupiter’s magnetic field interrupting that of Ganymede’s, and the effects observed thus far support this claim. Though Ganymede’s aurora should shift by about six degrees due to pull from the magnetic field of Jupiter, they only shift by two degrees, indicating the presence of a salt-abundant ocean. This ocean would likely be found about 100 kilometers beneath the icy surface of the planet.

Although this idea is still forming, there will be more concrete evidence for Ganymede’s ocean after the dispatch of Europe’s JUICE (Jupiter Icy Moon Explorer) spacecraft, which should launch in the early 2020s and arrive around Jupiter shortly after 2030. The goal for JUICE is for the craft to fly by Jupiter and some of the planet’s other moons, and then fall into orbit around Ganymede in order to send pictures and other data of the moon back to Earth.

Sources: NASA Solar System Exploration, BBC World

The Biggest Volcano in the Solar System

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astro201, blog5, mars, olympus mons, plate tectonics, shield volcano, volcano

The biggest volcano in the solar system was discovered in 1971 by the space probe Mariner 9, though it is actually visible from most backyard telescopes. This volcano is called Olympus Mons and it is located on Mars. Its peak lies 14 miles above its base, making it more than four times taller than Mt. Everest. Its slope is very gradual, but the entire volcano is about the size of Arizona.

A digital reconstruction of Olympus Mons, The Museum of Unnatural Mystery

Olympus Mons is one of the key indicators for scientists on Earth that there is tectonic activity on Mars. It is unlikely that Olympus Mons is or was ever a stratovolcano (think tall, cone-shaped, and very explosive, such as Mt. Vesuvius or Mt. St. Helens) since it is very large and seems to have gradual lava flows down its sides that have built up the base, rather than intermittent explosive eruptions. Volcanoes like this on Earth, called shield volcanoes, often form above hotspots, hotter locations in the Earth’s mantle where magma rises to the surface and is ejected to the crust in slow, steady eruption of basaltic lava. The chain of Hawaiian islands are an example of this: as the Pacific plate moves northwest, volcanoes form above the hotspot but then move with the plate, only building up until that location on the plate is no longer above the hotspot (Space.com).

Astronomers have yet to find evidence of multiple tectonic plates on Mars, indicating that there is no plate movement or that the surface of the crust is just one big plate that may move with turbulence in the mantle. Thus, Olympus Mons has been sitting above the same hotspot since it first started to form (likely, since the hotspot first formed beneath the surface). The volcano thus had the opportunity to continue to grow and grow, layers of lava building up on top of each other with successive eruptions and creating the biggest volcano in the world. Evidence of these eruptions is visible in the multiple calderas seen on top of the volcano. Want to know more about Olympus Mons? Check out this informational page.

Curious about the biggest volcano on Earth? Read more here.

Mars One Mission

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astro201, astronauts, blog4, current events, mars, mars one, marsone, space travel

In our society, the career of an astronaut has been painted as an idealistic childhood dream job or the mythical title attached to names like Neil Armstrong and Sally Ride – names only found in history books. The astronauts, past and future, who set foot on the Moon or traveled to the International Space Station will not only go down in history for their valuable exploration outside Earth’s atmosphere, but for the emotional and physical risks they took upon going into space. It’s enough to make an average citizen like you or I ask themselves, “Would I do that? Would I risk my life to travel where no one else has ever gone?”

In fact, that’s exactly what Mars One is asking. In 2011, Bas Lansdorp and Arno Wielders launched the Netherlands-based company Mars One with one mission – to settle a human colony on Mars. The founders garnered support from scientists, academics, and businesspeople around the world, starting a fundraising campaign for the project and establishing a team of marketers, ambassadors, and advisers. Though there are many notable supporters of the project, a few include representatives from SpaceX and astrophysics professors from Cornell University and University of Arizona.

Proposed design for Living Units on Mars, individual living spaces for residents connected by hallways and powered by Living Support Systems, which use solar energy and provide water and breathable air. (Mars One)

Mars One started with a fifteen-year plan to establish human life on Mars, and has kept to that plan since 2011. They have started preparation on Living Support Systems for people to use while living on Mars, pods that would provide adequate breathable air, energy, and water for residents. The colony would also require Living Units, indoor units with facilities suitable for human habitation. Though travelers would eat freeze-dried food on the ten-month journey to the Red Planet, they would be charged with growing their own food while on Mars, specific types of plants that could sustain in the unusual conditions of lower gravity and a less dense atmosphere. Mars One hopes to start transport of materials in 2022, including a rover that would find a suitable place on the planet’s surface to establish a settlement – close enough to the equator to have the most efficient solar energy collectors but far enough North to make use of water potentially contained in the rusted soil.

Press conference held by Bas Lansdorp and Arno Wielders in 2013 with the mission of recruiting interested travelers for the project. (Mars One)

One of the most important parts of the mission is the people. Who would be crazy enough to get on a one-way spaceship to Mars with very little chance of survival, saying goodbye to everything they’ve ever known – including family and friends – forever? Mars One released a request for volunteers at press conferences in 2013 and received feedback from about 200,000 applicants worldwide. This list has since been narrowed down to 600, and will eventually be cut down to just four who will leave for Mars in 2024, after undergoing eight years of intense mental, physical, and technical training. Much of this training would be in isolated environments simulating conditions on the spaceship or while living on Mars.

There are many more details regarding the funding, preparation, technology development, and social support of this project that will be unraveled in coming years as the company moves forward with the project. But now I want to hear from you – what are the potential problems with a project like this? Would you risk everything you have established here on Earth to be part of the first extraterrestrial human settlement?

For more on the history and plan of Mars One, see here.

For interviews with potential colonists, see Universe Today and BBC News.

It’s About Time

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astro201, babylonian, blog3, calendar, egyptian, gregorian, history, leap year, month, roman, week, year

Most of us have calendars hung in our kitchens or virtual apps constantly berating us with times, dates, and upcoming holidays. But have you ever stopped to think about where calendars came from or why our society relies so devotedly on them? How did we decide to divide our time that way? Why did we all agree on the same calendar?

Modern Gregorian Calendar (Web Design Tunes)

Calendars were first used in the time of the Ancient Egyptians and Babylonians to help predict changes in weather, especially for the purpose of agriculture. Ancient farmers noticed that flooding or dry spells tended to happen over and over again, with equally spaced time in between each occurrence. If they could tell when floods or heavy rains would hit, farmers could prepare to irrigate this water efficiently to crops or to save it to use during subsequent droughts. Of course, it was hard to map out exactly when these events would occur, so ancient civilizations looked to patterns that were a little more reliable – the movement of the stars.

The Egyptians were the first to see that constellations, groups of stars seen with the naked eye, moved around the sky in predictable patterns. The twelve constellations that we think of as Zodiac signs even seemed to chase each other in a circle around the sky. The time that it took for one of these constellations to return to the same place in the sky (at the same time of night) was classified as a year. Years were subsequently divided into twelve months of thirty days each.

The Babylonians, existing shortly after the time of the Egyptians, went on to define the month as the time between identical crescent moons. It was at this point that the calendar became lunisolar – relying on patterns of motion of the Sun and Moon through the sky (See different types of calendars here. The next major calendar to come into play was that of the Romans. Its most important additions included February as a twenty-eight day month, the division of months into weeks of seven days, and the proclamation that leap years would occur every four years to keep the calendar in line with Earth’s revolutions around the Sun, which take about 365 days and 6 hours (See here for more about leap years). At this point, the calendar was important not only to keep track of agricultural patterns but also to sustain the logistics of an expanding economy, which reached from Rome to other parts of Europe, Africa, and Asia. (See Time Center’s History of the Western Calendar or Exovedate for more about the Roman calendar.)

The most recent calendar used in the Western world is the Gregorian calendar, which was endorsed by Pope Gregory XIII in 1582. It includes the omission of three leap days every four hundred years to account more exactly for Earth’s revolution around the Sun, which is really about ten minutes short of 365 days and 6 hours. The Gregorian calendar is the official calendar in Europe and in most parts of the world. However, other calendars are used by various cultures. For example, the Chinese calendar varies in number of days per year and adds a thirteenth month for leap years. Many Islamic calendars rely on local observations of moon cycles, which can vary slightly depending on the weather and the location of the observer, so they are not constant among regions or countries. For a list of more calendars in use today, see here.

Ancient Julian Calendar as used in Rome (Hotel Rome)

Astronomy and Religion in Germany: The Story of Johannes Kepler

Tags

astro201, history, HW6, Kepler, physics

Johannes Kepler (1571-1630)

Johannes Kepler’s work began when he apprenticed for Tycho Brahe in the year preceding Tycho’s death. Kepler was determined to find an orbit for Mars and to match this orbit to a perfect circle, as was thought of all celestial orbits during the time of Tycho’s observations. While other astronomers had been content with mapping the orbits of planets on two models, east-west and north-south, Kepler sought to craft a model that unified these two constituents of a planet’s orbit. This led him to his most important discovery, that planets orbit the Sun in elliptical shapes rather than perfect circular orbits. He summarized this discovery and the mathematical conclusions related to it in Kepler’s Laws of Planetary Motion, which are still widely accepted today. More importantly, Kepler set a precedent of investigating new ideas on the basis of concrete data rather than socially accepted beliefs. This was the first conclusion to break down the idea of celestial perfection. (Read more at Encyclopedia Britannica)

Several important changes were happening in Europe during the time that Johannes Kepler lived in Germany. Two of these were the Thirty Years’ War (1618-1648) and the defeat of the Spanish Armada (1588).

Thirty Years’ War (History Channel)

The Thirty Years’ War, which lasted from 1618 to 1648, marked one of the most important religious and political conflicts in Europe after the Renaissance. After a Spanish king sought to secularize areas under his influence, Protestants of the country rebelled, sparking a war among many of the most powerful countries in Europe at the time, including Spain, France, Sweden, Austria, and Germany. Most of the war was fought over thirty years on German territory, where Johannes Kepler resided for most of the war. Germany was split into two fierce groups, the Protestant half supported by England, the Dutch Republic, and Denmark, while much of Spain, Austria, and the rest of the Holy Roman Empire (those supporting the Pope) supported the Catholics. This war is known for some of the bloodiest battles and ruthless conditions in European history: nearly a quarter of the German population was killed during the Thirty Years’ War; however, this conflict also represented the end of physical religious conflict in Europe.

Defeat of the Spanish Armada (Elizabeth I Informational Site)

Until the end of the sixteenth century, Spain was the most powerful state in Europe, boasting a powerful navy fleet and ruthless monarchy. In the 1580s, King Phillip II prepared a fleet of Spanish ships – an armada – to invade England so that he could end the reign of Queen Elizabeth I, claim the throne, and ensure that England remained Roman Catholic (this was the same basic conflict that occurred during the Thirty Years’ War, but on a larger scale – that war encompassed all of Europe while this battle involved only Spain and Britain). In 1588, Phillip II planned an attack – from Spain through the English Channel and from the north using ships stationed in the Spanish Netherlands to overtake Britain. However, the English monarchy heard of the attack and was prepared, defeating the Spanish off the coast of Great Britain.

Another key historical figure who lived during the time of Kepler was Protestant hero Gustavus Adolphus (New World Encyclopedia).

Gustavus Adolphus was born in 1594 in Stockholm, Sweden and died in 1632 in Saxony, Germany. During his rule, he expanded Sweden’s economy, grew its role in European politics, built a fully functioning military, and introduced Sweden as one of the major European states, a legacy that continues today. Adolphus was known for being a brilliant military general, as shown in his successful battles led in Germany against the Catholic Spanish.

According to The Cosmic Perspective, Kepler was “deeply religious” (65) and thought that the study of astronomy and patterns in the heavens would help him better to relate with God and his religious study. When I first read this in the textbook, I thought it seemed a bit arbitrary – Kepler’s mathematical discoveries were more important than his motivation for studying astronomy. However, looking deeper into the historical context, the true time in which Kepler lived, it was easier to see that any type of scientific research could not have been separated from the religious atmosphere in Europe at this time. Politics, economics, and science were all governed by the religious affiliations of countries. Especially in Germany, Kepler would have been forced to think about the difference between Catholicism and Protestantism and to take part in the one of the bloodiest European wars as a civilian whose life could have been threatened by the fighting in his own country. Everything at this time was connected to religion. This also puts in perspective the difference between astronomy today and astronomy in the sixteenth and seventeenth centuries. Today, it would seem bizarre to study mathematical relationships and the laws of physics in order to be more in tune with religion; we have completely separated science and religion. However, in Kepler’s time science and religion were still very much connected, as many natural phenomena were explained in supernatural terms.

What Does It Mean to Have a Zodiac Sign?

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astro201, astrological signs, blog2, constellations, history, me, zodiac

Lots of people are aware that they have a Zodiac sign – a symbol associated with the time of year that they were born. “I’m a Capricorn,” or “Watch out for him, he’s a Leo,” are phrases that we use without really understanding what they mean. So what exactly does it mean to have a Zodiac sign?

The twelve astrological, or Zodiac, signs originate with the Babylonians around 2,000 B.C. (American Federation of Astrologers). These early astrologers had a thorough understanding of how the Sun seemed to move throughout the sky and how constellations – groups of stars – seem to circle the Earth during the course of one year. Though they believed that the contents of the universe rotated around the Earth, they observed correctly that certain groups of stars seem to return to the same place in the sky at the same time each year. The Sun appears to be closest to one of the twelve constellations at predictable times throughout the year. For example, the Sun is closest to the constellation Leo from mid-July to mid-August. The Babylonians assigned each constellation a name and designated each a period of days on the modern calendar, so that every day of the year was associated with a certain constellation.

In short, the astrological sign associated with a certain period of time on our calendar, a phase of thirty days at the end of one month and beginning of another, is derived from the constellation to which the Sun is closest during those days.

There is a twist in this story that the Babylonians did not consider, however. Since 2,000 B.C., astronomers have discovered that the Earth precesses on its axis, wobbling slightly like a top spinning on a table that stars to shake after a few seconds of spinning. This wobble actually occurs in a predictable cycle of 26,000 years, which slowly causes the time at which we see certain constellations in the sky to change. Halfway through the cycle, 13,000 years after the constellations were first observed, their locations will actually be completely reversed. Leo will be closest to the Sun in late January to early February. 26,000 years is a very long time, but it has been nearly 3,000 years since the Babylonains first delineated certain Zodiac signs. The effects of precession are already being seen, so some Zodiac signs really do not represent their true times on the calendar. People born at the beginning or end of an astrological period may, in fact, have a different Zodiac sign, as the Sun is closest to a different constellation during that time of year (Wikipedia).

Because this cycle will just continue to change as time goes on, it may just be easier to stick with the Zodiac signs determined by the Babylonians. For this reason, Z

A map of the Zodiac constellations (Before It’s News)

odiac signs actually give us a peek into the cultural and astronomical history of our world!