A simulation of galaxies during the era of deionization in the early Universe. Credit: M. Alvarez, R. Kaehler, and T. AbelCredit: M. Alvarez, R. Kaehler, and T. Abel
In the beginning, there was chaos.
Hot, dense, and packed with energetic particles, the early Universe was a turbulent, bustling place. It wasn’t until about 300,000 years after the Big Bang that the nascent cosmic soup had cooled enough for atoms to form and light to travel freely. This landmark event, known as recombination, gave rise to the famous cosmic microwave background (CMB), a signature glow that pervades the entire sky.
Now, a new analysis of this glow suggests the presence of a pronounced bruise in the background — evidence that, sometime around recombination, a parallel universe may have bumped into our own.
Although they are often the stuff of science fiction, parallel universes play a large part in our understanding of the cosmos. According to the theory of eternal inflation, bubble universes apart from our own are theorized to be constantly forming, driven by the energy inherent to space itself.
Like soap bubbles, bubble universes that grow too close to one another can and do stick together, if only for a moment. Such temporary mergers could make it possible for one universe to deposit some of its material into the other, leaving a kind of fingerprint at the point of collision.
Ranga-Ram Chary, a cosmologist at the California Institute of Technology, believes that the CMB is the perfect place to look for such a fingerprint.
The cosmic microwave background (CMB), a pervasive glow made of light from the Universe’s infancy, as seen by the Planck satellite in 2013. Tiny deviations in average temperature are represented by color. Credit: ESA and the Planck Collaboration.
After careful analysis of the spectrum of the CMB, Chary found a signal that was about 4500x brighter than it should have been, based on the number of protons and electrons scientists believe existed in the very early Universe. Indeed, this particular signal — an emission line that arose from the formation of atoms during the era of recombination — is more consistent with a Universe whose ratio of matter particles to photons is about 65x greater than our own.
There is a 30% chance that this mysterious signal is just noise, and not really a signal at all; however, it is also possible that it is real, and exists because a parallel universe dumped some of its matter particles into our own Universe.
After all, if additional protons and electrons had been added to our Universe during recombination, more atoms would have formed. More photons would have been emitted during their formation. And the signature line that arose from all of these emissions would be greatly enhanced.
Chary himself is wisely skeptical.
“Unusual claims like evidence for alternate Universes require a very high burden of proof,” he writes.
Indeed, the signature that Chary has isolated may instead be a consequence of incoming light from distant galaxies, or even from clouds of dust surrounding our own galaxy.
Albert Einstein in 1947. Credit: Library of Congress
At the end of the millennium, Physics World magazine conducted a poll where they asked 100 of the world’s leading physicists who they considered to be the top 10 greatest scientist of all time. The number one scientist they identified was Albert Einstein, with Sir Isaac Newton coming in second. Beyond being the most famous scientist who ever lived, Albert Einstein is also a household name, synonymous with genius and endless creativity.
As the discoverer of Special and General Relativity, Einstein revolutionized our understanding of time, space, and universe. This discovery, along with the development of quantum mechanics, effectively brought to an end the era of Newtonian Physics and gave rise to the modern age. Whereas the previous two centuries had been characterized by universal gravitation and fixed frames of reference, Einstein helped usher in an age of uncertainty, black holes and “scary action at a distance”.
A pretty crescent moon will be the first thing you'll see appear in the sky tonight. Look southwest shortly after sunset to spot it. Source: Stellarium
Clear night ahead? Let’s see what’s up. We’ll start close to home with the Moon, zoom out to lonely Fomalhaut 25 light years away and then return to our own Solar System to track down the 7th planet. Even before the sky is dark, you can’t miss the 4-day-old crescent Moon reclining in the southwestern sky. Watch for it to wax to a half-moon by Thursday as it circles Earth at an average speed of 2,200 mph (3,600 km/hr). That fact that it orbits Earth means that the angle the Moon makes with the sun and our planet constantly varies, the reason for its ever-changing phase.
You’ll see two and possibly three lunar “seas” tonight (Nov. 15). Only a portion of Mare Tranquilliitatis (Seas of Tranquility) is exposed. The large crater Janssen, 118 miles wide and 1.8 miles deep, is visible in binoculars. Credit: Virtual Moon Atlas / Legrande and Chevalley
With the naked eye you’ll be able to make two prominent dark patches within the crescent — Mare Crisium (Sea of Crises) and Mare Fecunditatis (Sea of Fecundity). Each is a vast, lava-flooded plain peppered with thousands of craters , most of which require a telescope to see. Not so Janssen. This large, 118-mile-wide (190-km) ring will be easy to pick out in a pair of seven to 10 power binoculars. Janssen is named for 19th century French astronomer Pierre Janssen, who was the first to see the bright yellow line of helium in the sun’s spectrum while observing August 1868 total solar eclipse.
Piscis Austrinus, the Southern Fish, has but one bright star, 1st magnitude Fomalhaut. It shines all by its lonesome in the south around 7 p.m. local time at mid-month. The star is located only 25 light years from Earth. Source: Stellarium
English scientist Norman Lockyer also observed the line later in 1868 and concluded it represented a new solar element which he named “helium” after “helios”, the Greek word for sun. Helium on Earth wouldn’t be discovered for another 10 years, making this party-balloon gas the only element first discovered off-planet!
See the fish now? Greek mythology tells us that Piscis Austrinus is the “Great Fish”, the parent of the two fish in the zodiacal constellation of Pisces the Fish. Source: Stellarium
Directing your gaze south around 7 o’clock, you’ll see a single bright star low in the southern sky. This is Fomalhaut in the dim constellation of Piscis Austrinus, the Southern Fish. The Arabic name means “mouth of the fish”. If live under a dark, light-pollution-free sky, you’ll be able to make out a loop of faint stars vaguely fish-like in form. Aside from being the only first magnitude star among the seasonal fall constellations, Fomalhaut stands out in another way — the star is ringed by a planet-forming disk of dust and rock much as our own Solar System was more than 4 billion years ago.
The planet Fomalhaut b orbits Fomalhaut inside a circumstellar disk of dust and rock, taking about 1,700 years to orbit. Brilliant Fomalhaut, represented by the small, white dot, has been masked from view, so astronomers could photograph the much fainter disk. Credit: NASA / ESA / Hubble Space Telescope
Within that disk is a new planet, Fomalhaut b, with less than twice Jupiter’s mass and enshrouded either by a cloud of dusty debris or a ring system like Saturn. Fomalhaut b has the distinction of being the first extrasolar planet ever photographed in visible light. The plodding planet takes an estimated 1,700 years to make one loop around Fomalhaut, with its distance from its parent star varying from about 50 times Earth’s distance from the sun at closest to 300 times that distance at farthest.
Shoot a diagonal across the Square of Pegasus to 4th magnitude Delta Piscium. Point your binoculars here and slide east to 4th magnitude Epsilon and 2° south to the planet Uranus shines at magnitude +5.7 and can be glimpsed with the naked eye from a dark sky site. Time shown is around 7 p.m. local time. See detailed map below. Source: Stellarium
Next, we move on to one of the more remote planets in our own solar system, Uranus. The 7th planet from the sun, Uranus reached opposition — its closest to Earth and brightest appearance for the year — only a month ago. It’s well-placed for viewing in Pisces the Fish after nightfall high in the southeastern sky below the prominent sky asterism, the Great Square of Pegasus.
Wide-field binocular view of Uranus’ travels now through next April. I’ve labeled several stars near the planet with their magnitudes, which are similar in brightness to Uranus, so you’ll know to tell them apart from the planet. The others are naked eye stars in Pisces. Source: Chris Mariott’s SkyMap
A telescope will tease out its tiny, greenish disk, but almost any pair of binoculars will easily show the planet as a star-like point of light slowly marching westward against the starry backdrop in the coming weeks. Check in every few weeks to watch it move first west, in retrograde motion, and then turn back east around Christmas. For those with 8-inch and larger telescopes who love a challenge, use this Uranian Moon Finder to track the planet’s two brightest moons, Titania and Oberon, which glimmer weakly around 14th magnitude.
We’ve barely scratched the surface of the vacuum with these offerings; they’re just a few of the many highlights of mid-November nights that also include the annual Leonid meteor shower, which peaks Tuesday and Wednesday mornings (Nov. 17-18). So much to see!
When WT1190F struck this atmosphere over the Indian Ocean around 6:20 Universal Time (12:20 a.m. CST) today , it broke apart into multiple fireballs against the blue sky. The object came down around 1:20 p.m. local time. Credit: IAC/UAE Space Agency/NASA/ESA
Clouds hampered observations from the ground in Sri Lanka during the re-entry of WT1190F overnight, but a team of astronomers captured spectacular images of the object from a high-flying plane over the Indian Ocean very close to the predicted time of arrival.
Peter Jenniskens of the SETI Institute and NASA Ames Research Center is shown here before the flight setting up the eleven staring cameras with a wider field of view, including two spectographic cameras, to catch the reentry. Credit: IAC/UAE Space Agency/NASA/ESA
The International Astronomical Center (IAC) and the United Arab Emirates Space Agency hosted a rapid response team to study the re-entry of what was almost certainly a rocket stage from an earlier Apollo moon shot or the more recent Chinese Chang’e 3 mission. In an airplane window high above the clouds, the crew, which included Peter Jenniskens, Mike Koop and Jim Albers of the SETI Institute along with German, UK and United Arab Emirates astronomers, took still images, video and gathered high-resolution spectra of the breakup.
Video and still imagery of WT1190F’s Reentry November 13, 2015
The group of seven astronomers hoped to study WT1190F’s re-entry as a test case for future asteroid entries as well as improve our understanding of space debris behavior. Photos and video show the object breaking up into multiple pieces in a swift but brief fireball. From the spectra, the team should be able to determine the object’s nature — whether natural or manmade.
Wide view of the colorful fireball and breakup when WT1190F struck Earth’s atmosphere. More than 20 cameras were used to record the event. Credit: IAC/UAE Space Agency/NASA/ESAAnimation from photos made on Nov. 12 when WT1190F was still in one piece in orbit about the Earth. Credit: Marco LangbroekFlying observatory. This Gulfstream 450 business jet, sponsored by United Arab Emirates and coordinated by Mohammad Shawkat Odeh from the International Astronomical Center, Abu Dhabi, was used by the team to observe and record the re-entry. Only five windows were available to make observations. Credit: IAC/UAE Space Agency/NASA/ESASETI Institute “staring cameras” used for wide field observations of the re-entry. Credit: IAC/UAE Space Agency/NASA/ESA
a short animation (spanning about 10 minutes) made out of my follow-up images. The first frame was obtained at 08:17UT while the second frame was obtained at 08:27UT of Nov, 12, 2015. (WT1190F is the star-like object at the centre while stars are trailed because the images were stacked on WT1190F motion). Credit: Ernesto Guido
No one’s 100% certain what WT1190F is — asteroid or rocket stage — but we are certain it will light up like a Roman candle when it re-enters Earth’s atmosphere around 6:20 Universal Time (12:20 a.m. CST) tomorrow morning Nov. 13.
Animation by Jost Jahn of WT1190F’s final hours as it races across the sky coming down off the coast of Sri Lanka
As described in an earlier story at Universe Today, an object discovered by the Catalina Sky Survey on Oct 3rd and temporarily designated WT1190F is expected to burn up about 60 miles (100 km) off the southern coast of Sri Lanka overnight. The same team observed it twice in 2013. Based upon the evolution of its orbit, astronomers determined that the object is only about six feet (2-meters) across with a very low density, making it a good fit for a defunct rocket booster, possibly one used to launch either one of the Apollo spacecraft or the Chinese Chang’e 3 lander to the Moon.
Below a plot of the last three orbits of WT1190F. The small red circle is the Earth. For scale, the large green circle is the orbit of the Moon. Notice that its final orbit takes straight into Earth. Credit: Bill Gray / Project Pluto
Additional observations of WT1190F have been made in the past few days confirming its re-entry later tonight. Checking the latest predictions on Bill Gray of Project Pluto’s page, the object will likely be visible from Europe about an hour before “touchdown”. To say it will be moving quickly across the sky is an understatement. Try about 3 arc minutes per second or 3° a minute! Very tricky to find and track something moving that fast.
Three 90-second exposures showing WT1190F zipping across the Rosette Nebula taken on Nov. 11, 2015 at the Konkoly Observatory in Hungary. Credit: Krisztián Sárneczky
58 minutes later, in the minute of time from 6:18 to 6:19 UT, WT1190F will move one full hour of right ascension and plummet 34° in declination while brightening from magnitude +8 to +4.5. If you’d like to attempt to find and follow the object, head over to JPL’s Horizons site for the latest ephemerides and orbital elements. At the site, make sure that WT1190F is in the Target Body line. If not, click Change and search for WT1190F in the Target Body field at the bottom of the window.
WT1190F re-Entry Trajectory. The object is expected to break up and fall harmlessly into the ocean. Credit: Bill Gray, Project Pluto
You’ll find updates at Bill Gray’s site. According to the most recent positions, the object will pass almost exactly in front of the Sun shortly before plunging into the ocean. Sri Lanka’s capital, Colombo, is expected to get the best views.
Because the mystery object’s arrival has been fairly well publicized, I hope to update you with a full report and photos first thing tomorrow morning. Like many of you, I wish I could see the show.
Gerard Kuiper, founder of the Lunar and Planetary Laboratory. Credit: lpl.arizona.edu
In the outer reaches of the Solar System, beyond the orbit of Neptune, lies a region permeated by celestial objects and minor planets. This region is known as the “Kuiper Belt“, and is named in honor of the 20th century astronomer who speculated about the existence of such a disc decades before it was observed. This disc, he reasoned, was the source of the Solar Systems many comets, and the reason there were no large planets beyond Neptune.
Gerard Kuiper is also regarded by many as being the “father of planetary science”. During the 1960s and 70s, he played a crucial role in the development of infrared airborne astronomy, a technology which led to many pivotal discoveries that would have been impossible using ground-based observatories. At the same time, he helped catalog asteroids, surveyed the Moon, Mars and the outer Solar System, and discovered new moons.
Leonid meteor storms. Taurid meteor swarms. Earth is no stranger to meteor showers, that’s for sure. Now, it turns out that the planet Mercury may experience periodic meteor showers as well.
The news of extraterrestrial meteor showers on Mercury came out of the annual Meeting of the Division of Planetary Sciences of the American Astronomical Society currently underway this week in National Harbor, Maryland. The study was carried out by Rosemary Killen of NASA’s Goddard Spaceflight Center, working with Matthew Burger of Morgan State University in Baltimore, Maryland and Apostolos Christou from the Armagh Observatory in Northern Ireland. The study looked at data from the MErcury Surface Space Environment Geochemistry and Ranging (MESSENGER) spacecraft, which orbited Mercury until late April of this year. Astronomers published the results in the September 28th issue of Geophysical Research Letters.
Micrometeoroid debris litters the ecliptic plane, the result of millions of years of passages of comets through the inner solar system. You can see evidence of this in the band of the zodiacal light visible at dawn or dusk from a dark sky site, and the elusive counter-glow of the gegenschein.
The orbit of comet 2P Encke. Image credit: NASA/JPL
Researchers have tagged meteoroid impacts as a previous source of the tenuous exosphere tails exhibited by otherwise airless worlds such as Mercury. The impacts kick up a detectable wind of calcium particles as Mercury plows through the zodiacal cloud of debris.
“We already knew that impacts were important in producing exospheres,” says Killen in a recent NASA Goddard press release. “What we did not know was the relative importance of comet streams over zodiacal dust.”
This calcium peak, however, posed a mystery to researchers. Namely, the peak was occurring just after perihelion—Mercury orbits the Sun once every 88 Earth days, and travels from 0.31 AU from the Sun at perihelion to 0.47 AU at aphelion—versus an expected calcium peak predicted by researchers just before perihelion.
STEREO A catches sight of comet 2P Encke. Image credit: NASA/STEREO
A key suspect in the calcium meteor spike dilemma came in the way of periodic Comet 2P Encke. Orbiting the Sun every 3.3 years—the shortest orbit of any known periodic comet—2P Encke has made many passages through the inner solar system, more than enough to lay down a dense and stable meteoroid debris stream over the millennia.
With an orbit ranging from a perihelion at 0.3 AU interior to Mercury’s to 4 AU, debris from Encke visits Earth as well in the form of the November Taurid Fireballs currently gracing the night skies of the Earth.
The Encke connection still presented a problem: the cometary stream is closest to the orbit of Mercury about a week later than the observed calcium peak. It was as if the stream had drifted over time…
Comet 2P Encke, captured by NASA’s MESSENGER spacecraft. Image credit: NASA/Johns Hopkins/APL/SW Research Institute
Enter the Poynting-Robertson effect. This is a drag created by solar radiation pressure over time. The push on cometary dust grains thanks to the Poynting-Robertson effect is tiny, but it does add up over time, modifying and moving meteor streams. We see this happening in our own local meteor stream environment, as once great showers such as the late 19th century Andromedids fade into obscurity. The gravitational influence of the planets also plays a role in the evolution of meteor shower streams as well.
Researchers in the study re-ran the model, using MESSENGER data and accounting for the Poynting-Robertson effect. They found the peak of the calcium emissions seen today are consistent with millimeter-sized grains ejected from Comet Encke about 10,000 to 20,000 years ago. That grain size and distribution is important, as bigger, more massive grains result in a smaller drag force.
This finding shows the role and mechanism that cometary debris plays in exosphere production on worlds like Mercury.
“Finding that we can move the location of stream to match MESSENGER’s observations is gratifying, but the fact that the shift agrees with what we know about Encke and its stream from independent source makes us confident that the cause-and-effect relationship is real, says Christou in this week’s NASA Goddard press release.
Launched in 2004, MESSENGER arrived at Mercury in March 2011 and orbited the world for over four years, the first spacecraft to do so. MESSENGER mapped the entire surface of Mercury for the first time, and became the first human-made artifact to impact Mercury on April 30th, 2015.
The joint JAXA/ESA mission BepiColombo is the next Mercury mission in the pipeline, set to leave Earth on 2017 for insertion into orbit around Mercury on 2024.
An interesting find on the innermost world, and a fascinating connection between Earth and Mercury via comet 2P Encke and the Taurid Fireballs.
Godfrey Kneller's 1689 portrait of Isaac Newton at age 46.
Credit: Isaac Newton Institute
The 17th century was an auspicious time for the sciences, with groundbreaking discoveries being made in astronomy, physics, mechanics, optics, and the natural sciences. At the center of all this was Sir Isaac Newton, the man who is widely recognized as being one of the most influential scientists of all time and as a key figure in the Scientific Revolution.
An English physicist and mathematician, Newton made several seminal contributions to the field of optics, and shares credit with Gottfried Leibniz for the development of calculus. But it was Newton’s publication of Philosophiæ Naturalis Principia Mathematica (“Mathematical Principles of Natural Philosophy”), for which he is most famous. Published in 1687, this treatise laid the foundations for classical mechanics, a tradition which would dominate scientists’ view of the physical universe for the next three centuries.
Early Life:
Isaac Newton was born on January 4th, 1643, – or December 25th, 1642 according to the Julian Calendar (which was in use in England at the time) – in Woolsthorpe-by-Colsterworth, a hamlet in the county of Lincolnshire. His father, for whom he was named, was a prosperous farmer who had died three months before his birth. Having been born prematurely, Newton was small as a child.
His mother, Hannah Ayscough, remarried when he was three to a Reverend, leaving Newton in the care of his maternal grandmother. His mother would go on to have three more children with her new husband, which became Newton’s only siblings. Because of this, Newton apparently had a rocky relationship with his stepfather and mother for some time.
William Blake’s Newton (1795), depicted as a divine geometer. Credit: William Blake Archive/Wikipedia
By the time Newton was 17, his mother was widowed again. Despite her hopes that Newton would become a farmer, like his father, Newton hated farming and sought to become an academic. His interests in engineering, mathematics and astronomy were evident from an early age, and Newton began his studies with an aptitude for learning and inventing that would last for the rest of his life.
Education:
Between the ages of 12 and 21, Newton was educated at The King’s School, Grantham, where he learned Latin. While there, he became the top-ranked student, and received recognition for his building of sundials and models of windmills. By 1661, he was admitted to Trinity College, Cambridge, where he paid his way by performing a valet’s duties (what was known as a subsizar).
During his first three years at Cambridge, Newton was taught the standard curriculum, which was based on Aristotelian theory. But Newton was fascinated with the more advanced science and spent all his spare time reading the works of modern philosophers and astronomers, such as René Descartes, Galileo Galilei, Thomas Street, and Johannes Kepler.
The result was a less-than-stellar performance, but his dual focus would also lead him to make some of his most profound scientific contributions. In 1664, Newton received a scholarship, which guaranteed him four more years until he would get his Masters of Arts degree.
David Loggan’s print of Trinity College, Cambridge, showing Nevile’s Great Court (foreground) and the then-new Wren Library (background). Credit: Cantabrigia Illustrata/Cambridge (1690)
In 1665, shortly after Newton obtained his B.A., the university temporarily closed due to the outbreak of the Great Plague. Using this time to study at home, Newton developed a number of ideas he had which would eventually cement to become his theories on calculus, optics and the law of gravitation (see below).
In 1667, he returned to Cambridge and was elected as a fellow of Trinity, though his performance was still considered less than spectacular. However, in time, his fortunes improved and he gained recognition for his abilities. In 1669, he received his M.A. (before he had turned 27), and published a treatise expounding on his mathematical theories for dealing with infinite series.
By 1669, he succeeded his one-time teacher and mentor Isaac Barrow – a theologian and mathematician who discovered the fundamental theorem of calculus – and became the Lucasian Chair of Mathematics at Cambridge. In 1672, he was elected a Fellow of the Royal Society, which he would remain a part of until the end of his life.
Scientific Achievements:
While studying at Cambridge, Newton maintained a second set of notes which he entitled “Quaestiones Quaedam Philosophicae” (“Certain Philosophical Questions“). These notes, which were the sum total of Newton’s observations about mechanical philosophy, would lead him to discover the generalized binomial theorem in 1665, and allowed him to develop a mathematical theory that would lead to his development of modern calculus.
Newton’s experiment using a prism revealed that light is refracted based on color. Credit: britannica.com
However, Newton’s earliest contributions were in the form of optics, which he delivered during annual lectures while holding the position of Lucasian Chair of Mathematics. In 1666, he observed that light entering a prism as a circular ray exits in the form of an oblong, demonstrating that a prism refracts different colors of light at different angles. This led him to conclude that color is a property intrinsic to light, a point which had been debated in prior years.
In 1668, he designed and constructed a reflecting telescope, which helped him prove his theory. From 1670 to 1672, Newton continued to lecture on optics and investigated the refraction of light, demonstrating that the multicoloured spectrum produced by a prism could be recomposed into white light by a lens and a second prism.
He also demonstrated that colored light does not change its properties, regardless of whether it is reflected, scattered, or transmitted. Thus, he observed that color is the result of objects interacting with already-colored light, rather than objects generating the color themselves. This is known as Newton’s theory of color.
The Royal Society asked for a demonstration of his reflecting telescope in 1671, and the organization’s interest encouraged Newton to publish his theories on light, optics and color. This he did in 1672 in a small treatise entitled Of Colours, which would later be published in a larger volume containing his theories on the “corpuscular” nature of light.
Replica of Newton’s second Reflecting telescope that he presented to the Royal Society in 1672. Credit: Wikipedia Commons
In essence, Newton argued that light was composed of particles (or corpuscles), which he claimed were refracted by accelerating into a denser medium. In 1675, he published this theory in a treatise titled “Hypothesis of Light“, in which he also posited that ordinary matter was composed of larger corpuscles and about the existence of an ether that transmitted forces between particles.
After discussing his ideas with Henry More, an English theosophist and a member of the Cambridge Platonists, Newton’s interest in alchemy was revived. He then replaced his theory of an ether existing between particles in nature with occult forces, based on Hermetic ideas of attraction and repulsion between particles. This reflected Newton’s ongoing interest in both the alchemical and scientific, for which there was no clear distinction at the time.
In 1704, Newton published all of his theories on light, optics and colors into a single volume entitled Opticks: Or, A treatise of the Reflections, Refractions, Inflections and Colours of Light. In it, he speculated that light and matter could converted into one another through a kind of alchemical transmutation, and verged on theories of sound waves in order to explain repeated patterns of reflection and transmission.
While later physicists favored a purely wavelike explanation of light to account for the interference patterns and the general phenomenon of diffraction, their findings owed a great deal to Newton’ theories. Much the same is true of today’s quantum mechanics, photons, and the idea of wave–particle duality, which bear only a small resemblance to Newton’s understanding of light.
Excerpt from Newton’s “Quaestiones Quaedam Philosophicae”, a collection of observations that would lead to his development of modern calculus. Credit: newtonproject.sussex.ac.uk
Though both he and Leibniz are credited with having developed calculus independently, both men became embroiled in a controversy over who discovered it first. Though Newton’s work in developing modern calculus began in the 1660s, he was reluctant to publish it, fearing controversy and criticism. As such, Newton didn’t publish anything until 1693 and did not give a full account of his work until 1704, whereas Leibniz began publishing a full account of his methods in 1684.
However, Newton earlier works in mechanics and astronomy involved extensive use of calculus in geometric form. This includes methods involving “one or more orders of the infinitesimally small” in his 1684 work, De motu corporum in gyrum (“On the motion of bodies in orbit”), and in Book I of the Principia, which he referred to as “the method of first and last ratios”.
Universal Gravitation:
In 1678, Newton suffered a complete nervous breakdown, most likely due to overwork and an ongoing feud with fellow Royal Society member Robert Hooke (see below). The death of his mother a year later caused him to become increasingly isolated, and for six years he withdrew from correspondence with other scientists, except where they initiated it.
During this hiatus, Newton renewed his interest in mechanics and astronomy. Ironically, it was thanks to a brief exchange of letters in 1679 and 1680 with Robert Hooke that would lead him to make his greatest scientific achievements. His reawakening was also due to the appearance of a comet in the winter of 1680–1681, about which he corresponded with John Flamsteed – England’s Astronomer Royal.
Thereafter, Newton began considering gravitation and its effect on the orbits of planets, specifically with reference to Kepler’s laws of planetary motion. After his exchanges with Hooke, he worked out proof that the elliptical form of planetary orbits would result from a centripetal force inversely proportional to the square of the radius vector.
Newton communicated his results to Edmond Halley (discoverer of “Haley’s Comet”) and to the Royal Society in his De motu corporum in gyrum. This tract, published in 1684, contained the seed that Newton would expand to form his magnum opus, the Principia. This treatise, which was published in July of 1687, contained Newton’s three laws of motion. These laws stated that:
When viewed in an inertial reference frame, an object either remains at rest or continues to move at a constant velocity, unless acted upon by an external force.
The vector sum of the external forces (F) on an object is equal to the mass (m) of that object multiplied by the acceleration vector (a) of the object. In mathematical form, this is expressed as: F=ma
When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.
Together, these laws described the relationship between any object, the forces acting upon it and the resulting motion, laying the foundation for classical mechanics. The laws also allowed Newton to calculate the mass of each planet, calculate the flattening of the Earth at the poles and the bulge at the equator, and how the gravitational pull of the Sun and Moon create the Earth’s tides.
In the same work, Newton presented a calculus-like method of geometrical analysis using ‘first and last ratios’, worked out the speed of sound in air (based on Boyle’s Law), accounted for the precession of the equinoxes (which he showed were a result of the Moon’s gravitational attraction to the Earth), initiated the gravitational study of the irregularities in the motion of the moon, provided a theory for the determination of the orbits of comets, and much more.
This volume would have a profound effect on the sciences, with its principles remaining canon for the following 200 years. It also informed the concept of universal gravitation, which became the mainstay of modern astronomy, and would not be revised until the 20th century – with the discovery of quantum mechanics and Einstein’s theory of General Relativity.
Newton and the “Apple Incident”:
The story of Newton coming up with his theory of universal gravitation as a result of an apple falling on his head has become a staple of popular culture. And while it has often been argued that the story is apocryphal and Newton did not devise his theory at any one moment, Newton himself told the story many times and claimed that the incident had inspired him.
In addition, the writing’s of William Stukeley – an English clergyman, antiquarian and fellow member of the Royal Society – have confirmed the story. But rather than the comical representation of the apple striking Netwon on the head, Stukeley described in his Memoirs of Sir Isaac Newton’s Life (1752) a conversation in which Newton described pondering the nature of gravity while watching an apple fall.
“…we went into the garden, & drank thea under the shade of some appletrees; only he, & my self. amidst other discourse, he told me, he was just in the same situation, as when formerly, the notion of gravitation came into his mind. “why should that apple always descend perpendicularly to the ground,” thought he to himself; occasion’d by the fall of an apple…”
John Conduitt, Newton’s assistant at the Royal Mint (who eventually married his niece), also described hearing the story in his own account of Newton’s life. According to Conduitt, the incident took place in 1666 when Newton was traveling to meet his mother in Lincolnshire. While meandering in the garden, he contemplated how gravity’s influence extended far beyond Earth, responsible for the falling of apple as well as the Moon’s orbit.
Sapling of the reputed original tree that inspired Sir Isaac Newton to consider gravitation, located on the grounds of Cambridge. Credit: Wikipedia Commons/Loodog
Similarly, Voltaire wrote n his Essay on Epic Poetry (1727) that Newton had first thought of the system of gravitation while walking in his garden and watching an apple fall from a tree. This is consistent with Newton’s notes from the 1660s, which show that he was grappling with the idea of how terrestrial gravity extends, in an inverse-square proportion, to the Moon.
However, it would take him two more decades to fully develop his theories to the point that he was able to offer mathematical proofs, as demonstrated in the Principia. Once that was complete, he deduced that the same force that makes an object fall to the ground was responsible for other orbital motions. Hence, he named it “universal gravitation”.
Various trees are claimed to be “the” apple tree which Newton describes. The King’s School, Grantham, claims their school purchased the original tree, uprooted it, and transported it to the headmaster’s garden some years later. However, the National Trust, which holds the Woolsthorpe Manor (where Newton grew up) in trust, claims that the tree still resides in their garden. A descendant of the original tree can be seen growing outside the main gate of Trinity College, Cambridge, below the room Newton lived in when he studied there.
Feud with Robert Hooke:
With the Principia, Newton became internationally recognized and acquired a circle of admirers. It also led to a feud with Robert Hooke, with whom he had a troubled relationship in the past. With the publication of his theories on color and light in 1671/72, Hooke criticized Newton in a rather condescending way, claiming that light was composed of waves and not colors.
A historical reconstruction of what Robert Hooke looked like. Credit: Wikipedia/Rita Greer/FAL
While other philosophers were critical of Newton’s idea, it was Hooke (a member of the Royal Society who had performed extensive work in optics) that stung Newton the worst. This led to the acrimonious relationship between the two men, and to Newton almost quitting the Royal Society. However, the intervention of his colleagues convinced him to stay on and the matter eventually died down.
However, with the publication of the Principia, matters once again came to a head, with Hooke accusing Newton of plagiarism. The reason for the charge had to do with the fact that earlier in 1684, Hooke had made comments to Edmond Halley and Christopher Wren (also members of the Royal Society) about ellipses and the laws of planetary motion. However, at the time he did not offer a mathematical proof.
Nevertheless, Hooke claimed that he had discovered the theory of inverse squares and that Newton had stolen his work. Other members of the Royal Society believed the charge to be unfounded, and demanded that Hooke release the mathematical proofs to substantiate this claim. In the meantime, Newton removed all reference to Hooke in his notes and threatened to withdraw the Principia from subsequent publishing altogether.
Edmund Halley, who was a friend to both Newton and Hooke, tried to make peace between the two. In time, he was able to convince Newton to insert a joint acknowledgement of Hooke’s work in his discussion of the law of inverse squares. However, this did not placate Hooke, who maintained his charge of plagiarism.
Newton’s own copy of his Principia, with hand-written corrections for the second edition. Credit: Trinity Cambridge/Andrew Dunn
As time moved on, Newton’s fame continued to grow while Hooke’s continued to diminish. This caused Hooke to become increasingly embittered and more protective of what he saw as his work, and he spared no opportunity to lash out at his rival. The feud finally ended in 1703, when Hooke died and Newton succeeded him as president of the Royal Society.
Other Accomplishments:
In addition to his work in astronomy, optics, mechanics, physics and alchemy, Newton also had a keen interest in religion and the Bible. During the 1690’s, he wrote several religious tracts that addressed literal and symbolic interpretations of the Bible. For instance, his tract on the Holy Trinity – sent to the famous political philosopher and social theorist John Locke and unpublished until 1785 – questioned the veracity of 1 John 5:7, the description which the Holy Trinity is based on.
Later religious works – like The Chronology of Ancient Kingdoms Amended (1728) and Observations Upon the Prophecies of Daniel and the Apocalypse of St. John (1733) – also remained unpublished until after his death. In Kingdoms, he dealt with the chronology of various ancient kingdoms – the First Ages of the Greeks, ancient Egyptians, Babylonians, Medeans and Persians – and offered a description of the Temple of Solomon.
In Prophecies, he addressed the Apocalypse, as foretold within the Book of Daniel and Revelations, and espoused his belief that it would take place in 2060 CE (though other possible dates included 2034 CE). In his textual criticism titled An Historical Account of Two Notable Corruptions of Scripture(1754), he placed the crucifixion of Jesus Christ on April 3rd, AD 33, which agrees with a traditionally accepted date.
Portrait of Newton in 1702, painted by Godfrey Kneller. Credit: National Portrait Gallery, London
In 1696, he moved to London to take up the post of warden of the Royal Mint, where he took charge of England’s great recoining. Newton would remain in this post for 30 years, and was perhaps the best-known Master of the Mint. So serious was his commitment to the role that he retired from Cambridge in 1701 to oversee the reform of England’s currency and the punishment of counterfeiters.
As Warden, and afterwards Master, of the Royal Mint, Newton estimated that 20 percent of the coins taken in during the Great Recoinage of 1696 were counterfeit. Conducting many investigations personally, Newton traveled to taverns and bars in disguise to gather evidence, and conducted more than 100 cross-examinations of witnesses, informers, and suspects – which led to the successful prosecution of 28 counterfeit coiners.
Newton was a member of the Parliament of England for Cambridge University in 1689–90 and 1701–2. In addition to being President of the Royal Society in 1703, he was an associate of the French Académie des Sciences. In April 1705, Queen Anne knighted Newton during a royal visit to Trinity College, Cambridge, making him the second scientist to be knighted (after Sir Francis Bacon).
Death and Legacy:
Towards the end of his life, Newton took up residence at Cranbury Park near Winchester with his niece and her husband, where he would stay until his death. By this time, Newton had become one of the most famous men in Europe and his scientific discoveries were unchallenged. He also had become wealthy, investing his sizable income wisely and bestowing sizable gifts to charity.
Newton’s tomb in Westminster Abbey. Credit: Wikipedia Commons/Klaus-Dieter Keller
At the same time, Newton’s physical and mental health began to decline. By the time he reached 80 years of age, he began experiencing digestive problems and had to drastically change his diet and lifestyle. His family and friends also began to worry about his mental stability, as his behavior became increasingly erratic.
Then, in 1727, Newton experienced severe pain in his abdomen and lost consciousness. He died in his sleep on the next day, on March 2oth, 1727 (Julian Calendar; or March 31st, 1727, Gregorian Calendar) at the age of 84. He was buried in tomb at Westminster Abbey. And as a bachelor, he had divested much of his estate to relatives and charities during his final years.
After his death, Newton’s hair was examined and found to contain mercury, probably resulting from his alchemical pursuits. Mercury poisoning has been cited as a reason for Newton’s eccentricity in later life, as well as the nervous breakdown he experienced in 1693. Isaac Newton’s fame grew even more after his death, as many of his contemporaries proclaimed him to be the greatest genius who ever lived.
These claims were not without merit, as his laws of motion and theory of universal gravitation were unparalleled in his the time. In addition to being able to bring the orbits of the planets, the Moon, and even comets into one coherent and predictable system, he also invented modern calculus, revolutionized our understanding of light and optics, and established scientific principles that would remain in use for the following 200 years.
Albert Einstein was one of Newton’s many admirers, claiming that to Newton, nature was “an open book, whose letters he could read without effort”. Credit: Ferdinand Schmutzer/Public Domain
In time, much of what Newton espoused would be proven wrong, thanks largely to Albert Einstein. With his General Theory of Relativity, Einstein would prove that time, distance and motion were not absolutes, but dependent on the observer. In so doing, he overturned one of the fundamental precepts of universal gravitation. Nevertheless, Einstein was one of Newton’s greatest admirers and acknowledged a great debt to his predecessor.
In addition to calling Newton a “shining spirit” (in a eulogy delivered in 1927 on the 200th anniversary of Newton’s death), Einstein also remarked that “Nature to him was an open book, whose letters he could read without effort.” On his study wall, Albert Einstein is said to have kept a picture of Newton, alongside pictures of Michael Faraday and James Clerk Maxwell.
A survey of Britain’s Royal Society was also conducted in 2005, where members were asked who had the greater effect on the history of science: Newton or Einstein. The majority of the Royal Society’s members agreed that overall, Newton had a greater impact on the sciences. Other polls conducted in recent decades have produced similar results, with Einstein and Newton vying for first and second place.
It is not easy thing to be living during one of the most auspicious times in history. Moreover, it is not easy in the midst of all of that to be blessed with an insight that will lead one to comes up with ideas that will revolutionize the sciences and forever alter the course of history. But throughout it all, Newton maintained a humble attitude, and summarized his accomplishments best with the famous words: “If I have seen further it is by standing on the shoulders of giants.“
A November rain hails from the Sickle of the Lion.
Hot on the heels of the October Orionids and the Halloween fireballs of the Taurid meteors comes the Leonid meteor shower. On most years, the Leonids are a moderate shower, with hourly local rates reaching around 20. Once every 33 years, however, the Leonids are responsible for putting on one of the greatest astronomical shows ever witnessed, producing a grand storm with a zenithal hourly rate topping thousands per hour.
The orientation of the Earth and the relative positions of the Sun, Moon and the Leonid meteor radiant on November 17th at 4:00 UT. Image credit: Stellarium
Prospects for 2015
First, the bad news. 2015 isn’t forecast to be a ‘storm year’ for the Leonids, though that shouldn’t stop a vigilant observer from watching. The good news is, we’re just about midway betwixt the storm years of 1998-99 and 2031-32. The Leonids intensify once every 33 years, and if the increased activity seen in the late 1990s was any indication, we’d bet we’ll start seeing a pickup in rates from the Leonids in the late 2020’s or so. The good news for 2015, however, is that the peak for the Leonids occur on November 18th at around 4:00 Universal Time (UT)/ (11:00 PM EST on November 17th). This places the waxing crescent Moon out of the picture, just a day before reaching First Quarter phase. New Moon for November 2015 occurs on November 11th at 17:47 UT/12:47 PM EST.
A composite of the 2014 Leonids. Image credit: Alan Dyer/Amazing Sky Photography
Fun fact: the August Perseids, November Leonids and the December Geminid meteor showers are spaced out on the calendar in such a way that, when the Moon phase is favorable for one shower on a particular year, it is nearly always favorable across all of them.
The Leonids are mildly active from November 6th through November 30th, and though the above prediction for activity in 2015 favors European longitudes at dawn, some predictions have the peak arriving up to seven hours early this year.
A simulated ‘Leonid storm.’ Note the true position of the radiant in the center of the backwards ‘?’ asterism is slightly offset. Image credit: Stellarium
The Leonids are the dusty remnants laid down by periodic comet 55P Tempel-Tuttle on its 33-year path through the inner solar system. The Leonids are fast-movers, hitting the Earth nearly head-on in the dawn. You can see this in the relative position of the radiant, which rises in mid-November around 11PM local, and reaches the zenith around 6AM local time.
A late season Leonid meteor from 2014. Image credit: The UK Monitoring network (UKMON)
Often bluish in color, the Leonids hit the Earth’s atmosphere at over 70 km/sec… almost the fastest theoretical speed possible. For best results, watch for Leonids to spike in activity close to local dawn.
A 1799 woodcut depicting the Leonids at sea. Image credit: Public Domain
The Leonids have a storied history, going back 902 AD report from Arabic annals of the ‘Year of Stars.’ The Great Meteor Storm of 1833 dazzled (and terrified) residents of the eastern seaboard of the United States, and the spectacle not only inspired astronomer Denison Olmsted to pioneer studies into the fledgling field of meteor shower science, but has been attributed to adding fervor to many of the religious revivalist movements that sprang up in the 1830s in the United States as well.
The last outburst from the Leonids that reached such an apocalyptic scale was in 1966, when observers across the southwestern United States reported hourly rates approaching an amazing ZHR=144,000. Witnesses that remember this spectacle say it produced an illusion reminiscent of the Star Trek ‘warp speed’ effect, as Earth rammed headlong into the dense Leonid meteor stream.
Our own personal encounter with a Leonid meteor storm in 1998 from the dark desert skies of Kuwait wasn’t quite that intense, but thrilling to see nonetheless. Rates neared one every few seconds towards sunrise, with several fireballs punctuating the action, lighting up the desert floor. Here, as US coalition forces were on the verge of unleashing what would become Operation: Desert Fox over Iraq, the Universe was putting on a fireworks show of its own.
The Leonid meteor storms are the stuff of astronomical legend, a once in a lifetime event. Ever since we witnessed just what the Leonids are capable of, we never miss this annual shower, as we remember one night back in 1998, and look forward to the storms of 2032.
Here’s what the Leonids have been doing on previous recent years:
Radio observations were carried out from the Allen Telescope Array of the reputed megastructure-encompassed star KIC 8462852.
Astronomers at the SETI institute (search for extraterrestrial intelligence) have reported their findings after monitoring the reputedmegastructure-encompassed star KIC 8462852. No significant radio signals were detected in observations carried out from the Allen Telescope Array between October 15-30th (nearly 12 hours each day). However, there are caveats, namely that the sensitivity and frequency range were limited, and gaps existed in the coverage (e.g., between 6-7 Ghz).
Lead author Gerald Harp and the SETI team discussed the various ideas proposed to explain the anomalous Kepler brightness measurements of KIC 8462852, “The unusual star KIC 8462852 studied by the Kepler space telescope appears to have a large quantity of matter orbiting quickly about it. In transit, this material can obscure more than 20% of the light from that star. However, the dimming does not exhibit the periodicity expected of an accompanying exoplanet.” The team went on to add that, “Although natural explanations should be favored; e.g., a constellation of comets disrupted by a passing star (Boyajian et al. 2015), or gravitational darkening of an oblate star (Galasyn 2015), it is interesting to speculate that the occluding matter might signal the presence of massive astroengineering projects constructed in the vicinity of KIC 8462582 (Wright, Cartier et al. 2015).”
One such megastructure was discussed in a famous paper by Freeman Dyson (1960), and subsequently designated a ‘Dyson Sphere‘. In order to accommodate an advanced civilisation’s increasing energy demands, Dyson remarked that, “pressures will ultimately drive an intelligent species to adopt some such efficient exploitation of its available resources. One should expect that, within a few thousand years of its entering the stage of industrial development, any intelligent species should be found occupying an artificial biosphere which completely surrounds its parent star.” Dyson further proposed that a search be potentially conducted for artificial radio emissions stemming from the vicinity of a target star.
The SETI team summarized Dyson’s idea by noting that Solar panels could serve to capture starlight as a source of sustainable energy, and likewise highlighted that other, “large-scale structures might be built to serve as possible habitats (e.g., “ring worlds”), or as long-lived beacons to signal the existence of such civilizations to technologically advanced life in other star systems by occluding starlight in a manner not characteristic of natural orbiting bodies (Arnold 2013).” Indeed, bright variable stars such as the famed Cepheid stars have been cited as potential beacons.
The Universe Today’s Fraser Cain discusses a ‘Dyson Sphere‘.
If a Dyson Sphere encompassed the Kepler catalogued star, the SETI team were seeking in part to identify spacecraft that may service a large structure and could be revealed by a powerful wide bandwidth signal. The team concluded that their radio observations did not reveal any significant signal stemming from the star (e.g., Fig 1 below). Yet as noted above, the sensitivity was limited to above 100 Jy and the frequency range was restricted to 1-10 Ghz, and gaps existed in that coverage.
Fig 1 from Harp et al. (2015) conveys the lack of radio waves emerging from the star KIC 8462852 (black symbols), however there were sensitivity and coverage limitations (see text). The signal emerging from the quasar 3c84 is shown via blue symbols.
What is causing the odd brightness variations seen in the Kepler star KIC 8462852? Were those anomalous variations a result of an unknown spurious artefact from the telescope itself, a swath of comets temporarily blocking the star’s light, or perhaps something more extravagant. The latter should not be hailed as the de facto source simply because an explanation is not readily available. However, the intellectual exercise of contemplating the technology advanced civilisations could construct to address certain needs (e.g., energy) is certainly a worthy venture.
