RASC Vancouver’s Scott McGillivray talks about this year’s Perseid Meteor Shower and SpaceX catching a rocket capsule with a net-wielding boat.
The flashes of fireflies on a warm summer night create enchanting light shows. Fireflies exist on every continent, in North America they are most common in Eastern Canada and the United States. Ten species of fireflies in five genera have been recorded in British Columbia but adults of only two species produce flashed bioluminescent signals. Fireflies have captured the human imagination for centuries and have frequently been the focus of art, literature, and cultural traditions.
A jungle full of fireflies, few trees like this were really filled up with hundreds of fireflies in small area. They displayed a synchronized light pattern a mating time where males put up the light show to attract females. The moonlit forest added the fill light while the stars in background completed the frame to witness this most dramatic scene – Credit: Abhijit Juvekarf, Malshej, Ghat, India.7 Jun 2014.
Here come real stars to fill the upper skies,
And here on earth come emulating flies,
That though they never equal stars in size,
(And they were never really stars at heart)
Achieve at times a very star-like start.
Only, of course, they can’t sustain the part.
Fireflies in the Garden by Robert Frost
This year’s World Firefly Day was on July 6-7, 2019 and the theme this year was “Fireflies need dark nights.” There is growing evidence that suggests light pollution contributes to the decline of firefly populations across the globe. Fireflies emit light to attract males, communicate, and defend territory. Scientists have found that light pollution reduces flashing activities in a fireflies.
The most important step to take to protect nocturnal species like fireflies from light pollution is to follow responsible lighting practices that reduce or eliminate unnecessary outdoor lighting. You can also fight light pollution by helping #MeasureTheSkyBC with you smart phone or tablet:
- Download the Lost of The Night app from the Apple App Store or Google Play Store
- Measure the sky glow at your location using the app on a night when the Moon is below the horizon – the dates Aug 22 – Aug 31 around the next new Moon are a great time to make measurements.
- Submit your measurement and send an email to [email protected] for a chance to win prizes.
Another cultural connection between fireflies and space is the 2002-2003 TV serfies “Firefly” that follows the the adventures of the renegade crew of Serenity, a “Firefly-class” spaceship.
Solar Cycle 25 is coming to life. For the second time this month, sunspots belong to Solar Cycle 25 have been identified. A sunspot, numbered AR2744, emerged in the Sun’s southern hemisphere on July 8th, 2019 and has been identified as being part of Solar Cycle 25 according to spaceweather.com.
The solar cycle is a cycle of low to high magnetic activity that the Sun goes through approximately every 11 years. The sun is currently in a period of minimum magnetic activity at the end of Solar Cycle 24. The appearance of sunspot AR2744 heralds the possible start of Solar Cycle 25.
How is AR2744 indentified as being part of Solar Cycle 25?
A key piece of evidence relies on identifying the polarity of the magnetic fields of sunspots. Sunspots generally group together in pairs to form the poles of solar magnets as if a giant horseshoe magnet was placed under the Sun’s surface.
One sunspot of each pair has a positive (“+” or “north”) polarity where the magnetic field is directed outward. The other spot in the pair has the opposite negative polarity (“-” or “south”) where the magnetic field is directed inward. The polarity of sunspots is highlighted in magnetogram images which show the strength of magnetic fields and their polarity. The image below is a magnetogram image of the area around AR2744 where areas with “+” polarity appear as green while areas of “-” polarity appear as red/orange.
Sunspot pairs are usually oriented parallel to the Sun’s equator so a sunspot pair can be classified as either:
- “+/-” as in the image above, or
- the opposite orientation “-/+”, as if the horseshoe magnet was rotated 180 degrees.
Sunspots in the Sun’s southern hemisphere from the old Solar Cycle 24 have a -/+ polarity. AR2744 appeared in the southern hemisphere but its polarity, as seen in the above image is “+/-“, making it a part of Solar Cycle 25. This reasoning is based on G.H. Hale’s observations in the first decade of the 20th century:
- The same polarity pattern is seen in each solar hemisphere. For example, all cycle 24 sunspots in the southern hemisphere have the same “-/+” polarity.
- Opposite polarity pattern are seen in north vs southern hemisphere. So all cycle 24 sunspots in the northern hemisphere have “+/-” polarity.
- Polarity patterns reverse in each subsequent solar cycle. The “-/+” polarity of cycle 24 southern spots flips to “+/-” for cycle 25.
It is common for sunspots belonging to both cycles to appear during the transition from one cycle to the next so we will have to keep an eye out for more spots belonging to cycle 25.
Sometimes stuff gets in the way when you are looking for
faint Kuiper belt objects near the edge of the solar system. That is what happened to a team of scientists using the Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory in Chile. The huge 520-megapixel camera attached to the telescope also had Jupiter in its view leading to the discovery of 10 new moons for the largest planet in the solar system.
An additional year of observations verified the orbits of the moons and their status was confirmed by the International Astronomical Union on July 17th, 2019.
The moons are all less than 3 km in diameter and orbit Jupiter much further out than the large primary moons. The moons of Jupiter have been classified into a few groups:
- The inner group of primary or Galilean moons (purple),
- The prograde group that orbit Jupiter in the same direction as Jupiter’s rotation (blue), and
- The retrograde group that orbit in the opposite direction to Jupiter’s rotation (red).
The newly discovered moons mostly fall into the above groups with 2 in the prograde group and 7 in retrograde group.
One outlier orbits in the same direction as Jupiter’s rotation but is located within the retrograde group. This outlier has tentatively been named “Valetudo” after Jupiter’s great-granddaughter. Its orbit with the retrograde group is unstable and a collision is likely at some point.
The new discovery brings Jupiter’s total up to 79 moons – the most of any planet in our solar system. Four moons of Jupiter were discovered by Galileo: Io, Europa, Ganymede, and Callisto. They are among the largest satellites in the Solar System and are easily visible in a small telescope or even binoculars (if they are supported or held steady enough).
Jupiter is currently located about 20 degrees above the horizon, due south, at 10:00 pm PDT. Come out to Starry Nights at SFU’s Burnaby Campus on Friday, July 26th from 09:00 pm to midnight to get your own look at the Galilean moons (weather permitting) – Io slips in behind Jupiter at 09:30 pm but Europa, Ganymede, and Callisto will appear as tiny points of light with Europa on one side and Ganymede & Callisto lined up on the other side.
Join us for a gathering with light snacks, door prizes, moon talks and short films followed by observing Jupiter and Saturn at the Trottier Observatory.
Saturday, July 20, 2019, 7:30 PM to Midnight
- Celebration and Talks: 07:30pm to 10:00pm in Room SWH 10081 (Saywell Hall). Limited to 150 people.
- Observing at the Trottier Observatory: 10:00pm to midnight (weather permitting)
Simon Fraser University, Burnaby Campus – find us on a map
RSVP and View the event on meetup
Admittance to the observatory is on a first-come, first-served basis. For a summary of our Observatory House Rules and Starry Night Etiquette, please visit:
Speakers: Ted Stroman and Leigh Cummings
Abstract: On October 4th, 1957, the USSR launched the first successful orbital satellite into space. By the end of the 1960s, only 13 years later, the USA successfully landed 2 men on the Moon. Ted Stroman is an expert on the history of the Apollo program that brought that to be. Leigh Cummings has been trying to keep up with the developments in the effort to return to the Moon by the next decade. We hope to give an entertaining and eye-opening picture of where and how we have been to the Moon and where and how we might go on.
One of the interesting Apollo facts you will learn at the talk is that the first Apollo 11 “feet” to touch the Moon were Canadian! The four landing gear system “legs” (or “struts”) on the Apollo Lunar Module descent stages were built by the Canadian company Heroux-Devtek, based in Quebec. These landing legs were constructed of a light-weight aluminum and compressible honeycomb design to aid in shock absorption.
Neil Armstrong landed so gently that the legs did not compress on impact leaving the Lunar Module’s ladder positioned quite high above the surface.
Join us on July 20th to learn more.
A visitor to our Canada Day table noticed that the tide seem very low in False Creek and wondered if it had any connection to the Total Solar Eclipse on July 2nd in South America.
The answer is yes. A solar eclipse must happen at new Moon when the the Moon is lined up directly between the Sun and the Earth.
Tides are mostly caused by the gravity of the Moon as it pulls the water on the near-side away from the Earth and pulls the Earth away from the water on the far side. With the Sun aligned with the Moon during an eclipse – the Sun is also pulling in the same direction and so the tides are larger.
Total solar eclipses are awesome events to see but not that special for tides. The same alignment and high tides occur at every new Moon regardless of whether or not there is an eclipse. Such high tides have been give the name “spring tide” (technically, spring tides also include the high tides that occur when the Moon is full)..
Other factors cause the highest tides which are colloquially known as “King Tides”. The orbit of the Moon around the Earth, and the Earth around the Sun are not perfectly circular and tides are larger when
- The Moon is closest to the Earth – the Moon is at perigee
- The Earth is closest to the Sun – the Earth is at perihelion
Back in Sept 2015, the above factors plus others combined to give extreme tides that will not be matched again until 2034! Read more about the Extreme Tides September 28 in 2015.
You might think there is not much to see on the Sun as experts predict a long, deep solar minimum in 2019. But you can try to prove them wrong by observing the sun at the Canada Day celebration in Maple Ridge‘s Memorial Peace Park from 12 pm to 6 pm on Monday, July 1st, 2019.
RASC Vancouver will have several special hydrogen-alpha (Ha) telescopes setup for the public to safely observe solar features such as flares, prominences, sunspots, and filaments. Hydrogen-alpha (Ha) telescopes use special filters that block almost all the light from the sun except for a narrow band of red light emitted when hydrogen is energized in sun’s chromosphere. Many think that Ha’s greatest highlights are the prominences shot out from the sun’s limb, and large prominences can occur even during a solar minimum.
If the weather and the sun cooperate then you will be able to see some on Canada Day. In the the mean time, take a look at the pictures below, taken by amateur astronomers, to see what solar features can look like in Ha.
Asteroid Day events are scheduled during the week of 30 June, the date of the largest asteroid impact of Earth in recorded history (Tunguska). Asteroid Day promotes awareness and provides knowledge to the general public about the importance of asteroids in the formation of our universe and the role they play in our solar system today. Asteroid Day TV started streaming on June 27th at 4am PDT.
Below are some tidbits about asteroids to help celebrate the day.
An Asteroid with a Comet-Like Tail
Observations from December and early January show that Asteroid (6478) Gault has developed a comet-like tail. This small asteroid is spining so fast that it is throwing off material from its surface.
Observe Asteroid 18 Melpomene at Opposition
Asteroid 18 Melpomene is currently well placed for observation, located in the constellation Scutum. It is at opposition on July 2nd 2019 and will reach its highest point 31° above the southern horizon around 1 am PDT. It will be visible in small telescopes as its visual magnitude is 9.2
Asteroid Re-named as a Tribute to Brian Eno
Astronomers renamed the asteroid formerly known as 81948 (2000 OM69) to “Eno” as a tribute to musician, composer and record producer Brian Eno. Eno was described as “an experimental sculptor of sound” and has become synonymous with ambient music. The honour came just a day after Eno was presented with the Stephen Hawking Medal at Starmus 2019 for the reissue of his 1983 album, “Apollo: Atmospheres and Soundtracks”.
Asteroids can have a Moon
About 15% of asteroids are in binary systems, and the smaller of these pairs is referred to as a moon. The Asteroid Impact and Deflection Assessment (AIDA) mission proposes to send a pair of space probes to study and demonstrate the effects of crashing a spacecraft into an asteroid. NASA’s Dart spacecraft will impact the moonlet, “Didymoon”, that orbits the larger asteroid Didymos. The European Space Agency’s Hera spacecraft will follow-up with a detail survey of the results of the impact. The mission will help explore the possibility of deflecting this type of asteroid and formulate ways to protect Earth from harmful space rocks.
Asteroid with Enough Metal to Make Everyone Rich
It’s estimated that asteroid Psyche 16 contains various metals worth $10,000 quadrillion Mining all its metal could make everyone on Earth a billionaire, or could destroy commodity prices and cause the world’s economy to collapse. Pysche 16 is one of the ten most massive asteroids in he asteroid belt. It was discovered by the Italian astronomer Annibale de Gasparis in 1852
Scientists classify Psyche 16 as a M-type (metallic) asteroid that is comprised mostly of metallic iron and nickel similar to Earth’s core. Psyche 16 could be an exposed core of an early planet, maybe as large as Mars. NASA is launching a mission to probe the asteroid in the summer of 2022. The “Discovery Mission” should arrive at Psyche 16 in 2026. This will be the first mission to explore a world of metal rather than one of rock and ice.
Black holes, event horizons, and singularities are weird concepts that just seem to go together. A black hole is a region of such strong gravitational pull that nothing can escape not even light. An event horizon is the boundary of black hole – anything within the event horizon can never escape while light originating right at the event horizon could escape. A singularity is a location within a black hole where the density and gravitational force becomes infinite.
In the case of a black hole, the singularity is hidden from view by its event horizon. So Black holes are singularities that are “dressed in black” by their event horizon and undressing a Black Hole would reveal a “Naked Singularity” – if such objects actually exist.
All black holes have an event horizon whose size or radius is proportional to the the mass the black hole according an equation derived by the German astrophysicist Karl Schwarzschild:
Rg = 2GM/c2.
where M is the mass, G is the universal gravitational constant and c is speed of light. The following table shows the radius the event horizon based on the masses of a few well-know objects.
|The Recently imaged black hole in the Messier 87 galaxy||2×1013 |
|Sagittarius A* – the black hole at the center of our galaxy||1×1010|
|A 70 kg Human||1×10−25|
In other words, you could create a small black hole by compressing the Earth down to a less than than the size of a Canadian dime.
The physicist, Roger Penrose, showed that every black hole contains a singularity but he could not prove that every singularity also had an event horizon. The potential existence of these naked singularities is a challenge to theoretical physics – a model of singularities would require dealing with infinities and the unification of warped space-time from general relatively with the weird behaviour of very small objects from quantum theory. If naked singularities physically exist then they could be potentially be observed because they are not hidden by an event horizon. A 2017 paper in Physical Review suggests a way that naked singularities could be detected and distinguished from black holes.
Penrose proposed that some physical principle, not yet understood, excluded the existence of naked singularities (except for Big Bang singularity). This is known as the “cosmic censorship conjecture“.
Stephen Hawking found the idea of naked singularities to be obscene and felt that singularities should be “decently hidden” in places where they cannot be seen. He bet Dr. Kip Thorne and another physicist, John Preskill that these abominations cannot possibly occur. The loser agreed “to reward the winner with clothing to cover the winner’s nakedness.” The clothing was to be embroidered with “a suitable concessionary message.”
Hawking conceded the bet after a computer simulation by Matthew Choptuik of the University of Texas in Austin showed that under very rare and contrived circumstances a black hole might collapse in such a way that its singularity would be exposed, stripped for all to see. Having lost the bet on a technicality, Dr. Hawking provided Preskill with an embarrassing t-shirt while giving a talk to 1,000 people at Caltech. The t-shirt featured a nearly-naked lady and the slogan “Nature Abhors a Naked Singularity”. Hawking also placed another bet:
Whereas Stephen W. Hawking (having lost a previous bet on this subject by not demanding genericity) still firmly believes that naked singularities are an anathema and should be prohibited by the laws of classical physics,
And whereas John Preskill and Kip Thorne (having won the previous bet) still regard naked singularities as quantum gravitational objects that might exist, unclothed by horizons, for all the Universe to see,
Therefore Hawking offers, and Preskill/Thorne accept, a wager that
When any form of classical matter or field that is incapable of becoming singular in flat spacetime is coupled to general relativity via the classical Einstein equations, then
A dynamical evolution from generic initial conditions (i.e., from an open
set of initial data) can never produce a naked singularity
(a past-incomplete null geodesic from scri-plus).
The loser will reward the winner with clothing to cover the winner’s nakedness. The clothing is to be embroidered with a suitable, truly concessionary message.
Stephen W. Hawking, John P. Preskill, Kip S. Thorne
Pasadena, California, 5 February 1997
The new bet is still standing!
What well-known double star has a companion that appears to orbit the primary once every 24 hours?
The answer is a well-known star that looks like a single star to our naked eye but is actually a binary system with a smaller companion star. The companion star is visible in a telescope and appears to orbit the primary once every day. If you view this system through a 24 hour period, perhaps in Winter from above the Arctic Circle where it remains dark all day, then the companion would trace one complete orbit around the primary and end up back where it started. If you are impatient then scroll down to the video below for the answer.
A double star is a pair of stars that appear close to each other as viewed from Earth, especially with the aid of a telescope. In binary systems, the stars are physically bound together by gravity so they are in orbit around each other. Binary stars are important to astronomers as knowledge of their motions allows direct calculation of stellar mass.
The star Alberio, the head of swan in the constellation Cygnus, is considered to be one of the most beautiful double stars. It is a binary system with the brighter gold star and the dimmer blue star orbiting around their common center of mass.
The video below shows the answer to the double star puzzle produced by simulating the binary system using the SkySafari app.
Polaris, the north star, is a binary system with a companion SAO 305, also known as Alpha Ursae Minoris B or Polaris B. If you pay attention to the date/time at the bottom of video then you can see that SAO 305 does, in fact, appear to orbit Polar once every 24 hours.
But the puzzle is a deception, of course, because all the stars that we can view from the Northern Hemisphere appear to orbit Polaris every 24 hours as seen in the following video with a wider field.
These “orbits” appear because of the rotation of the Earth rather than the motion of the stars.
But the universe keeps things interesting – In 1929, another very close companion was found near Polaris making it a system of three stars that are gravitationally bound together.
Credit: This puzzle came from Glenn Chaple‘s Oberving Basics column in the May issue of Astronomy Magazine, published Tuesday, April 2, 2019.