Astronomy in October


Starry night in October

From eNature in the USA:

October’s Skies Are Great For Stargazing

Posted on Friday, September 26, 2014 by eNature

October skies are busy ones! The longer nights and cooler, clear skies of fall make for some great stargazing. And there’s a lot more than just stars to see up there!

Highlights Include Stars, Planets And Well-known Constellations

Our night sky sparkles with stars, billions of them, inspiring lovers, poets, explorers, and scientists. The closest star to Earth, the Sun, warms our planet and makes life possible.

Stars are composed mainly of hydrogen gas. Their light comes from the energy produced at their cores by nuclear fusion. This energy emerges from the surface of a star as the light we see and as ultraviolet light, X rays, and radio waves.

Our sun, which is at a stage in its life (called the main sequence stage) when it converts hydrogen at its core to helium and energy, maintains a fairly steady energy output. It’s been at this stage for about four and half billion years, and perhaps another five billion years remain until it uses up its hydrogen fuel. When a star becomes exhausted, the fuel at its center begins to expand and its surface cools. Depending on its mass, the star then turns into a red giant or a supergiant. Our sun will become a red giant.

In a red giant, both helium and hydrogen are transmuted into heavier elements and energy. After swelling to many times its former size and using up its store of helium, a red giant sheds its outer envelope. The star’s interior begins to shrink, and its surface heats up, becoming white hot. It’s now a white dwarf, an extremely dense star with the approximate mass of the Sun compressed into a size about that of the Earth. A teaspoonful of the matter of such a star would weigh many tons.

October Constellations

The Summer Triangle still graces the sky in early fall. At 9:00 p.m. on October evenings, it lies in the northwestern quadrant of the celestial dome. One corner, Altair, the alpha (or brightest) star in the constellation Aquila, the Eagle, is almost due west. Vega, the blue-white alpha star in the constellation Lyra, the Harp, is about halfway up the northwestern sky. The third corner, marked by Deneb, the brightest star of Cygnus, the Swan, is about two-thirds of the way between the horizon and the zenith (the point straight overhead).

Hercules, the Strongman, lies low in the northwest, just below Vega. Ursa Major, the Great Bear, and its well-known asterism (a star shape within a larger constellation), the Big Dipper, are very low on the northern horizon. The Little Dipper, or Ursa Minor (the Little Bear), extends to the left of Polaris, the North Star, which marks the end of its handle.

In the northeastern quarter of the sky is Andromeda, the Princess. Nearby are her mother, Queen Cassiopeia, whose wide W shape is now angled like a number 3, and her father, King Cepheus, shaped like a child’s drawing of a house. Below the Princess and the Queen is Perseus, the Hero, who saved Andromeda from Cetus, the Sea Monster. The brightest stars in this part of the sky are the yellowish star Cappella, the alpha star in the pentagonal constellation Auriga, the Charioteer, and the reddish star Aldebaran, marking the eye of Taurus the Bull, low in the east. The V-shaped star cluster of the Hyades looks like an arrowhead pointing to the right. Aldebaran sits at the end of the bottom arm of the V. Above Aldebaran is the small but beautiful star cluster of the Pleiades, also known as the Seven Sisters.

High in the south and southeast are the stars of Pegasus, the Winged Horse ridden by Perseus. The curved, narrow A shape of Andromeda begins at the northeastern corner of an asterism called the Great Square of Pegasus and stretches into the northeastern sky. On a very dark, clear night you might be able to make out a fuzzy patch of light above the middle of the two lines of stars that form Andromeda; this is the Great Andromeda Galaxy, the most distant object the eye can see unaided by binoculars or a telescope.

Closer to the horizon in the southern part of the sky are Pisces, the Fish, and below it, the dim constellation Cetus, the Sea Monster. Culminating in the south is Aquarius, the Water Bearer. Capricornus, the Sea Goat, and some of the other faint “watery” constellations, including little Delphinus, the Dolphin, are in the southwest. Almost due south is one of the brightest stars in the sky, Fomalhaut, the alpha star in Piscis Austrinus, the Southern Fish. Fomalhaut is unfamiliar to most northern-latitude observers since it belongs to a Southern Hemisphere constellation that appears in northern skies only briefly and always low. There are no other bright stars in the southern sky at this time, so it’s unmistakable.

Northern lights in Scotland tonight


This video from Norway says about itself:

This video explains how particles originating from deep inside the core of the sun create northern lights, also called aurora borealis, on our planet.

From Scotland Now:

Scotland set for a beautiful Northern Lights display

Sep 12, 2014 00:01

SCOTLAND could be set for a beautiful display of the Northern Lights .

The bright dancing lights, known as the aurora borealis, could be on display in Scotland and across other parts on the UK tonight (Friday 12).

This is because there have been two large explosions on the Sun and huge amounts of magnetically charged particles have been hurled into space towards Earth.

Known as Coronal Mass Ejection (CME), they can produce many different colours, with green, pink, red, blue and yellow all possible.

Often the particles are deflected by the earth’s magnetic field, so the best places to witness it are close to the poles where the field is weakest.

The Met Office said it is expecting there to be some cloud and localised fog patches around on Friday night but there should also be some clear skies.

It recommends finding somewhere away from street lights and says the best chance of seeing the aurora will be around midnight.

Earlier this year, we told you that catching a glimpse of the Northern Lights topped a bucket list of things Scots wanted to do before they die .

A survey of 2000 people by the National Lottery placed seeing the aurora borealis natural phenomenon above any other personal desire.

See also here.

Earth and aurora borealis from space, video


This video says about itself:

9 September 2014

This timelapse video was made from images taken by ESA astronaut Alexander Gerst orbiting Earth on the International Space Station.

The video is offered in Ultra High Definition, the highest available to consumers. Be sure to change the settings in YouTube if your computer or television can handle it for the full effect.

The montage is made from a long sequence of still photographs taken at a resolution of 4256 x 2832 pixels at a rate of one every second. The high resolution allowed the ESA production team to create a 3840 x 2160 pixel movie, also known as Ultra HD or 4K.

Playing these sequences at 25 frames per second, the film runs 25 times faster than it looks for the astronauts in space.

The artistic effects of the light trails from stars and cities at night are created by superimposing the individual images and fading them out slowly.

Alexander Gerst is a member of the International Space Station Expedition 40 crew. He is spending five and a half months living and working on the ISS for his Blue Dot mission.

By Emily Thomas in the USA today:

A new video released Tuesday by the European Space Agency (ESA) shows the world like you’ve never seen it before: in super-high-definition 4K.

The stunning time-lapse video, seen above, was taken by ESA astronaut Alexander Gerst as he orbited Earth aboard the International Space Station–and paired with a mesmerizing house music soundtrack.

Watch as swirls of green from auroras borealis drift by, and streaks of blue and white stars zoom past Earth as it transitions from day to night. You’re in for a treat.

For maximum viewing pleasure, turn your YouTube settings up to 4K.

Galileo Galilei and the beginning of physics


This video says about itself:

Galileo (1975) – Joseph Losey (1)

This bio-film is based on Bertold Brecht‘s play about Galileo Galilei, the 17th century Italian who laid the foundations of modern science. Galileo made himself one of the world’s first telescopes and discovered the moons of Jupiter.

He supported Copernicus’ theory that the Earth revolved around the Sun. This brought him in conflict with the Catholic Church. By threatening him with torture, the Church forced him to recant his views in front of a tribunal, and sentenced him to house arrest. However, Galileo’s trials and theories inspired others like Newton and Kepler to prove that the Earth was not the centre of the Universe. Some years ago, the Pope accepted that Earth does revolve around the Sun and issued a rare apology for what the Church had done to Galileo, i.e., the Catholic Church recanted.

By Henry Allan and Bryan Dyne:

The beginning of modern physics

9 September 2014

Renaissance Genius: Galileo Galilei and His Legacy to Modern Science, David Whitehouse, Sterling, 2009 (US $24.95)

This volume is a welcome contribution to the study of the Italian Renaissance, written by the British archeologist David Whitehouse. It gives a comprehensive view of the world of the Italian Renaissance at a time when ideas, discoveries and new inventions accelerated the clash of science with the medieval institution of the Roman Catholic Church. The book’s primary focus is the life and work of Galileo Galilei (1564-1642), whose persecution by the Church reflects the tribulations of most of the progressive thinkers of the time.

The book was published to coincide with the 400th anniversary of the year when Galileo turned his significantly improved version of the telescope to the night skies and began to draw the phases of the moon. It is lavishly illustrated with paintings, photographs, and illustrations that depict the time in which Galileo lived, his life, friends, colleagues, adversaries and persecutors.

As Renaissance Genius shows, this was the time of the Inquisition and its imprisonment, torture, and heinous executions of those deemed “heretics.” This included anyone who challenged existing church doctrine, particularly those developing the new techniques of observation, experimentation and the combination of the two with mathematics. Among those persecuted were Giordano Bruno, Antonio de Dominis and Galileo himself.Galileo Galilei

Vincenzo Galilei, Galileo‘s father, was a mathematician and music theorist who challenged traditional beliefs in the infallibility of Greek philosophic thought backed by both church and state. He found, for example, that the practical application of experimentation disproved long-held beliefs of the ancient Greek philosopher Pythagoras on musical interval and pitch between two strings. Pythagoras had held that in the tuning of strings, the weights used to stretch the strings, the tension must be doubled. It turned out that in practice, the tension had to be quadrupled, not doubled, to produce a tone an octave higher. As Whitehouse explains:

“It is hard to underestimate the importance of this moment in Galileo’s life. He and his father had found a new harmony; a new set of mathematical laws that correlated the note produced by a string to its tension, and had done so by experiment. They had not looked up the answer in either an ancient Greek treatise nor sought the advice of some musical authority. This was the start of modern science: They had carried out an experiment and asked a question of nature itself. It was revolutionary. Vincenzo’s actions had unfolded the course of his son’s life in experimental physics.”

Later in life, Galileo would use experimental techniques to show that objects fall towards the Earth at the same rate, regardless of mass. That some objects seem to fall slower is because of air resistance, not a property of the objects themselves. This challenged the Aristotelian principle that claimed that heavier objects fall faster than lighter ones. The most famous of these experiments was done at the Leaning Tower of Pisa, when he released two identically shaped spheres of different masses from the top of the tower. The spheres, one of 100 pounds and the other only one pound, hit the ground at the same time.

Nearly 400 years later, astronaut David Scott of Apollo 15, carried out a similar experiment on the surface of the moon, releasing a feather and a metal hammer. Both struck the lunar surface at the same time. “Galileo was correct,” exclaimed Scott.

This video is called APOLLO 15 Hammer and Feather.

Galileo’s achievements also involve a number of inventions related to other fields of science. He developed the thermoscope, the predecessor of the thermometer, which was the first attempt to measure heat. The Venetian Senate awarded him a patent for a water-lifting machine used in irrigation that only used one horse. A friend in the tool-making trades helped Galileo develop a simple compass that could be used to gauge the distance and height of a target as well as measure the angle of elevation of a cannon’s barrel. While Galileo did not invent the telescope, which was first built in the Netherlands in 1608, he is credited with increasing the magnification by 20 to 30 times using advanced lens-crafting techniques.

His interest in telescopes was sparked in 1604 when a new “star” appeared in the constellation Ophiuchus. This followed an earlier appearance of a new star in 1572 that was studied by the Danish astronomer Tycho Brahe. Such occurrences challenged the long-held notion of both the Aristotelians and the Church that the heavens are perfect and unchanging. Always being one to pursue observations, Galileo sought a way to study the night sky in greater detail.

One of Galileo's early telescopes at the Museum of the History of Science in Florence, Italy

With his telescope, he began to paint the different phases of the moon and its observable dark and light spots. He showed the moon to his patron, the Duke of Tuscany, who was delighted. Galileo then observed the Pleiades star cluster, as well as the planet Jupiter. Through these observations, he discovered the four largest moons of Jupiter – Io, Callisto, Europa and Ganymede, and provided the first evidence of objects orbiting a body other than the Earth. This was the proof Galileo needed to become a fervent advocate of the Copernican model of the cosmos.

A similar realization was made during Galileo’s study of the phases of Venus, repeating in much greater detail observations done by Copernicus. After recording the pattern of sunlight reflected from Venus’ atmosphere, he realized that the only way such patterns could occur is if both Venus and Earth revolved around the Sun. Galileo published a book on his observations, which circulated throughout Europe.

Included in his observations were the recording of sunspots. By aiming the telescope at the Sun and letting the light pass through the telescope onto a white background, Galileo was able to sketch out the positions of sunspots and determine that such imperfections on the Sun both existed and changed with time. Both this observation and the experimental evidence that the Earth is not the center of the universe incurred the wrath of the Church.

Galileo before the Holy Office, painted by Joseph-Nicolas Robert-Fleury

Both the Greek philosopher Aristotle and the Vatican considered the sun a perfect and unblemished sphere. The stars themselves were seen as divinities, contributing to the growth of astrology. It was argued by church supporters that the observed sunspots must be satellites of the sun and not “imperfections” in its surface. Galileo stated that not only were sunspots on the surface of the sun, they changed their shapes, and both originated and dissolved on that sphere. This could only lead to one conclusion: the sun was not a perfect sphere.

Galileo’s popularity and a newly established science academy in Rome ensured the continued publication of his works and a certain defense against the Church and other professional enemies. However, the issue of sunspots became the spark for an open clerical attack upon Galileo.

The story of how this debate unfolded is but one example of how the church and its privileged office-holders used the Bible to defame scientists like Galileo. Galileo himself believed that nothing that was discovered in any way conflicted with Scripture and quoted an ecclesiastical historian, Cardinal Baronius (1538-1607), who had commented: “The Holy Ghost intended to teach us how to go to heaven, not how the heavens go.” This clever riposte did not save him. As Whitehouse points out:

“In his innate conservatism, Cardinal Bellarmine saw the Copernican universe as threatening to the social order. To him and to much of the Church’s upper echelon, the science of the matter was beyond their understanding — and in many cases their interest. They cared more for the administration and the preservation of Papal power than they did for getting astronomical facts right.”

In the end, Galileo was told by Bellarmine and the head of the Inquisition, Cardinal Agostino Oreggi, that Copernicus’ views were wrong and he was not to support them. Furthermore, he was ordered not to teach or defend Copernican theory in any way, either in his writings or verbally.

After Bellarmine and Pope Paul V died, Galileo still harbored great hopes that the new Pope, Urban VIII, his former friend Maffeo Barberini, would prove when elected to be much better than his predecessors. This was an illusion. He was summoned before an even more hostile Inquisition than the first time.

While Whitehouse speculates that for Barberini, being Pope “had gone to his head,” the more fundamental truth is, as he observed earlier, that the Church hierarchy as a whole viewed “the Copernican universe as threatening to the social order.” The Pope, no matter his individual origins, was bound by his place in medieval society to defend the status quo.

The reproductions in Whitehouse’s book of paintings and illustrations depicting book burnings, the burnings at the stake for heresy, and the humiliations endured by thousands at the hands of the Inquisition reinforce this point.

Renaissance Genius depicts how Galileo’s defense of the Copernican system and the subsequent discoveries by Kepler, Rene Descartes, and Isaac Newton not only established the beginnings of physics, but also led to the advances for science that have resulted in the modern space program, including the space probe named after Galileo and the Hubble space telescope, the most extraordinary advance in the technology which Galileo pioneered.

Whitehouse sums up the Galilean revolution by providing us with a very human portrait of the man, the history of his times and Galileo’s indispensable role in the advancement and popularization of science for humankind.

Spaceship Rosetta arrives at comet


This 4 August 2014 video is called Rosetta Probe Will Spiral In To Comet.

From the European Space Agency:

Rosetta arrives at comet destination

6 August 2014

After a decade-long journey chasing its target, ESA’s Rosetta has today become the first spacecraft to rendezvous with a comet, opening a new chapter in Solar System exploration.

Comet 67P/Churyumov–Gerasimenko and Rosetta now lie 405 million kilometres from Earth, about half way between the orbits of Jupiter and Mars, rushing towards the inner Solar System at nearly 55 000 kilometres per hour.

The comet is in an elliptical 6.5-year orbit that takes it from beyond Jupiter at its furthest point, to between the orbits of Mars and Earth at its closest to the Sun. Rosetta will accompany it for over a year as they swing around the Sun and back out towards Jupiter again.

Comets are considered to be primitive building blocks of the Solar System and may have helped to ‘seed’ Earth with water, perhaps even the ingredients for life. But many fundamental questions about these enigmatic objects remain, and through a comprehensive, in situ study of the comet, Rosetta aims to unlock the secrets within.

See also here. And here. And here. and here.

Perseid meteor shower next week


This video is called Whats Up for August Sky 2014 – Supermoon & Perseid Meteor Shower.

From eNature Blog in the USA:

Be Sure To Catch The Annual Perseid Meteor Shower Next Week

Posted on Monday, August 04, 2014 by eNature

The annual Perseid meteor shower should be visible in the night sky early next week, peaking between August 10 and August 13.

A waning Gibbous Moon (the phase following a full moon) may make it harder for observers to see the shower. Despite this, astronomers suggest that you try your luck at catching some Perseids before dawn on August 11, 12 and 13. At its peak, you can see 60 to a 100 meteors in an hour from a dark place away from the lights of civilization.

If your local weather cooperates, the best night for viewing is looking to beTuesday night— really more early Wednesday morning.

The best viewing hours should be between 11 p.m. and dawn, when the constellation Perseus is above the horizon. Although the meteors appear to come from Perseus, they actually are part of a debris trail left by Comet Swift-Tuttle, which the Earth encounters every August.

To spot meteors, find a dark-sky spot away from street lights. Perseids can appear anywhere in the sky; astronomers recommend looking in whatever direction the sky is darkest for you.

Earthsky.org has a great guide for determining the best time to catch the Perseids in your town.

Learn more about the night sky with our August Sky Guide.

Scientific American has a great overview of of the smaller meteor showers visible this month.