Light Pollution Concerns in Squamish

Pascal Pillot-Bruhat, our light pollution chair, was interviewed for the article “Let’s not starve for starlight” in the Squamish Chief.   The article notes that Squamish is taking steps to address light pollution:

The District of Squamish’s new Official Community Plan includes the recommendation that exterior lights should emit the minimum amount of light necessary. Outside lighting should be directed or shielded to illuminate the ground only and to prevent light pollution from encroaching onto adjacent properties, residential areas and environmentally sensitive areas

Image of Bortle scale used to measure light pollution
Bortle scale used to measure light pollution

 

 

 

 

Nova Newsletter – Nov/Dec 2017

Our NOVA Newsletter, for Nov-Dec 2017 is available as a hi-res or low-res pdf file.   An archive of older issues can be found on our Newsletter page.

Contents of Volume 2017, Issue 6, November-December-2017:

  • A Very Long Way Out by J. Karl Miller
  • President’s Message by Suzanna Nagy
  • A Failsafe Method to Charting and Locating Asteroids by Robert Conrad
  • Science Bash in Richmond by Suzanna Nagy

Spooky Space Images and Sounds

In preparation for Halloween, the RASC Vancouver observing group took at look at Mirach’s Ghost from the Trottier Observatory last Saturday night (Oct 28th, 2017).

Image of Mirach's Ghost
Mirach’s Ghost from Astronomy Picture of the Day on October 27, 2017. Image Credit: Kent Wood

Mirach’s Ghost is a faint galaxy that appears close to the bright star Mirach in Andromedae.   It is not particularly scary or spectacular but the universe offers up some additional Halloween themed images and sounds.

The Ghost of Jupiter (NGC 3242)
Jupiter’s Ghost. Image Credit: Rainer Sparenberg, Stefan Binnewies, Volker Robering, Capella Observatory

This ghostly image shows the disembodied remains of a dying star, called a planetary nebula. Planetary nebulas are sun-like stars that are in a late-stage of their life when their outer layers have sloughed off and are lit up by ultraviolet light from the central star. The Ghost of Jupiter is located approximately 1,400 light-years away in the constellation Hydra.

The Ghost of Saturn (NGC 7009)
Image of the Ghost of Saturn
The Ghost of Saturn. Image credit: ESO’s Very Large Telescope

The Saturn nebula is a planetary nebula located in the constellation of Aquarius. Its name derives from its shape, which resembles everyone’s favourite ringed planet seen edge-on.

The Owl Nebula (M97)
Image of the Owl Nebula
The Owl Nebula (M97). Image Credit Keith Quattrocchi

The Owl Nebula is a planetary nebula located near the bottom of the Big Dipper’s bowl.   It is one of the fainter objects in the Messier Catalog.

The Phantom Galaxy (M74)
Image of the Phantom Galaxy
The Phantom Galaxy (M74) as photographed by the Hubble Space Telescope in 2007. Image Credit: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration.

Messier 74 (M74) is a grand design spiral galaxy located in the constellation Pisces.  It has a diameter of 95,000 light years, almost the same size as the Milky Way. The galaxy is home to about 100 billion stars.

The Outer Limits Galaxy (NGC 891)
Image of the Outer Limits Galaxy
The Outer Limits Galaxy (NGC 891).

NGC 891 is an edge-on spiral galaxy located about 3.5o east of the double-star Almaak in Andromeda. The Hubble Space Telescope has rendered stunning detailed views of this system with its intricate dark dust lanes across its centre. The name “Outer Limits” galaxy came about because the galaxy was featured in the credits of an early incarnation of the famous “Outer Limits” TV series.

The Witch’s Broom Nebula (NGC 6960)
Image of the Witch's Broom Nebula
Witch’s Broom Nebula. Image Credit: T. A. Rector (U. Alaska), NOAO, AURA, NSF

Also known as the Veil Nebula,  the Witch’s Broom is a faint supernova remnant located in the constellation Cygnus. The Witch’s Broom actually spans about 35 light-years. The bright star in the frame is 52 Cygni, visible with the unaided eye from a dark location but unrelated to the ancient supernova remnant.

NASA’s Spooky Space Sounds

NASA has put together a compilation of elusive “sounds” of howling planets and whistling helium that is sure to make your skin crawl

 

 

Speeding between the Sun and Uranus

The Earth, in its speedy inner orbit, swung between the Sun and Uranus last week.  On Oct 19, 2017 Uranus reached opposition which implies that we are about as close to Uranus as we get and so it appears somewhat larger and brighter.   It is a good time to get a glimpse of Uranus, especially  with the weather forecast calling for a few nights with clear skies.

Aurora on Uranus
Composite images of auroras on Uranus captured with the Hubble Telescope,.  Image Credit: NASA, Laurent Lamy

Uranus’ current location is in the constellation Pisces and is positioned due south around midnight PDT.  Uranus is dim with a magnitude of 5.7 and is barely visible with naked eyes and then only from a very dark site.   It is visible with binoculars or small telescope but appears small with an apparent diameter of just 4.1 arc-seconds.  At higher magnifications, you might notice its disc-shape and its blue-green tint.  Don’t expect to see surface features on the ice giant;. Even giant professional telescopes can barely do that.

Originally Thought to be a Comet

William Herschel discovered Uranus in England on the night of March 13, 1781.  At first Herschel thought it was a comet, but it was confirmed as a planet several years later. Herschel tried to have his discovery named “Georgia Sidus” after King George III. Astronomer Johann Bode suggested naming it after the Greek deity Ouranos.

Its Cold There

Uranus is much closer to the Sun than Neptune but the minimum temperature on Uranus (-224 degrees C) is colder than Neptune, making Uranus the coldest planet in the solar system.

Lots of Dim Moons

Uranus has 27 known moons to date, five of which can be observed from earth. Only, the four largest are visible in amateur instruments. Ariel, Umbreil, Titania, and Oberson are all dimmer than 14th magnitude but may be visible in telescopes larger than 10 inches. The moons of Uranus are named after characters in the the works of Shakespeare and Alexander Pope.

The moons of Uranus imaged using the PlaneWave 0.7m telescope at the Trottier Observatory.  Image Credit Robert Conrad and the RASC Observing Group, Sept 28th, 2017

 

Long Days on a Titled Planet

Uranus nearly lies on its side with a tilt of about 98 degrees. Uranus completes a single rotation on its axis in about 17 hours. But the tilt of Uranus is so pronounced that one pole or the other is usually pointed towards the Sun. If you could stand on the north pole of Uranus at the start of its summer, you would see the Sun rise in the sky and circle around for 42 years (1/2 of a Uranian year). Then the Sun would finally dip down below the horizon and be followed by 42 years of winter darkness.

Less Surface Gravity than Earth

Uranus’ density is low at just 1.27 g/cm3 – the second-lowest density of any planet in the Solar System after Saturn.  Despite the fact that Uranus is 14.5 times as massive as the Earth, its significantly lower density means that you would only experience about 89% the force of Earth’s surface gravity, assuming you could stand on Uranus’ cloud tops.

Only been Visited Once

Only the Voyager 2 spacecraft has made a close approach to Uranus. On January 24th, 1986, it passed within 81,000 km of the cloud tops of Uranus and took thousands of photographs of the gas/ice giant and its moons before heading off towards Neptune. The possibility of sending the Cassini spacecraft from Saturn to Uranus was evaluated during a mission extension planning phase in 2009 but never came to fruition, as it would have taken about twenty years for Cassini to get to Uranus from Saturn.

Uranium Namesake

Uranium was discovered in 1789, just eight years after Uranus’ discovery, by the German chemist Martin Heinrich Klaproth.   Klaproth chose to name the new element in honour of the newly discovered planet.

Dark Rings

Uranus has dark coloured rings.   The rings are thought to made up of particles ranging in size from 0.2 to 20 meters that contain a mixture of ices, dust, and debris.  Their discovery in 1977 was serendipitous. Astronomers James L. Elliot, Edward W. Dunham, and Jessica Mink planned to use the occultation of the star SAO 158687 by Uranus to study the planet’s atmosphere. However, when their observations were analyzed, they found that the star disappeared briefly from view five times both before and after it was eclipsed by the planet. They deduced that a system of narrow rings was present.

Sailing to the Stars

“Chemistry will get you to Mars, but it won’t get you to the stars.” – Philip Lubin, Astrophysicist at UCSB.

The Planetary Society, NASA, and several aerospace companies are looking to utilize the power of sunlight to sail spacecraft to the stars.

Rendition of LightSail 2 - The Planetary Society
Rendition of LightSail 2 – The Planetary Society

LightSail is a citizen-funded project from The Planetary Society. In 2018, they are launching a small spacecraft on a Space X Falcon Heavy rocket into Earth orbit. Once in orbit, the LightSail 2 spacecraft will be propelled solely by sunlight, aiming to achieve the first controlled solar sail flight in Earth orbit.

LightSail 2 is a three unit cubesat – measuring just 10 x 10 x 30 cm and weighing less than 5 kg. It will deploy a Mylar sail that is roughly the size of two parking spots. The sail captures the momentum of sunlight:  as light reflects off the sail, most of its momentum is transferred, pushing on the sail, and accelerating the spacecraft. Unlike chemical rockets that provide short bursts of trust, solar sails provide a continuous thrust that can result in higher speeds over time.

Tilting the sail steers the spacecraft by changing the angle at which sunlight reflects off it.  The steering technology used in the LightSail 2 demonstration could be used to maneuver cubesats in Earth orbit without fuel. LightSail 2’s performance could also inform NASA’s Near-Earth Asteroid (NEA) Scout solar sail mission which is scheduled to launch in 2019.

Solar sailing is also considered a promising means of interstellar space travel. Last year, the Breakthrough Initiatives announced a plan to send a fleet of small solar sails to Alpha Centauri. An Earth-bound laser array would zap the sails in Earth orbit, accelerating them to 20 percent the speed of light. They would reach the Alpha Centauri system in roughly 20 years and could send back images of the recently-discovered planet Proxima b. One of the first steps is to figure out how to compress a entire spacecraft on to a chip that weighs less than 1 gram.

There has already been some progress on this task. A number of prototype Sprites –  fully functional space probes on a single circuit board weighing just 4 grams.– achieved Low Earth Orbit in June, 2017.

 

 

Canadian Scientists Study Effects of Space Weather

Space weather has the potential to wreak havoc on satellite technologies and cause blackouts. Earlier this month, two large solar flares disrupted radio communication. In March 1989, a similar solar event knocked out power to much of Quebec. Canada intends to study how space weather could impact utility networks, banks, hospitals, and other infrastructure.

A powerful solar flare erupted on the surface of the sun on Sept 6th, 2017, disrupting radio communications. (Helioviewer/NASA
A powerful solar flare erupted on the surface of the sun on Sept 6th, 2017, disrupting radio communications. (Helioviewer/NASA)

Pierre Langlois is part of a team at the Canadian Space Agency looking to understand how space weather could impact the country’s infrastructure. The agency is hiring a contractor to perform a first-of-its-kind study in Canada to assess how its most critical systems, like electrical grids, could be affected by space weather, according to a request for proposals posted on the government’s tenders page.

Space weather refers to the environmental conditions in space and in Earth’s magnetosphere, ionosphere and thermosphere that are due to events that occur on the Sun. Most solar events are associated with sunspots so Canadian scientists at Space Weather Canada monitor sunspots on a daily basis for eruptions such as Solar flares and Coronal Mass Ejectons (CMEs). They provide a space weather forecast that includes Vancouver and the Lower Mainland.

Both solar flares and CMEs involve huge explosions of energy but are otherwise quite different. Flares can last minutes to hours. Most of the energy from solar flares reaches Earth as light. It takes eight minutes for the light from a solar flare to reach us. Some of the energy released in the flare also accelerates very high energy particles that can reach Earth in tens of minutes. The energy from a flare can disrupt the area of the atmosphere through which radio waves travel.

In contrast, CME events hurl solar matter into space. Traveling over a million miles per hour, the hot magnetized particles from a CME take up to three days to reach Earth. The CME particles may interact with Earth’s magnetic fields to produce fantastic displays of northern lights. The magnetic changes can also affect human technologies: High frequency radio waves can be degraded, GPS coordinates stray by a few yards, and electrical currents are created in utility grids.

The new study on the impact of space weather arose out of a recommendation from the United Nations earlier this year. The study has a budget of $300,000 and will take 15 months. The agency wants risk assessments done on the impact space weather could have on a variety of infrastructure systems from road and railway transportation to satellite-based services such as navigation, telecommunication, and military efforts, as well as on government services, banks and hospitals.

Nova Newsletter – Sept/Oct 2017

Our NOVA Newsletter, for Sept-Oct 2017 is available as a hi-res or low-res pdf file.   An archive of older issues can be found on our Newsletter page.

Contents of Volume 2017, Issue 5, September-October-2017:

  • The 2017 Total Eclipse from Madras, OR by Gordon Farrell
  • President’s Message by Suzanna Nagy
  • A Message from our Observing Chair by Robert Conrad
  • Aug 21 Eclipse Event at Science World by Suzanna Nagy
  • The Missed Perseids by J. Karl Miller
  • RASC’s National Star Party 2017: A Coast to Coast Event by Leigh Cummings

Image of Surface and Atmosphere on Antares

A team of astronomers, led by Keiichi Ohnaka, of the Universidad Católica del Norte in Chile, used the ESO’s Very Large Telescope Interferometer (VLTI) at the Paranal Observatory in Chile to capture an image of Antares that reveals surface details!  This is the best image of the surface and atmosphere of any star other than the Sun.

Antares Surface Details
Surface details on Antares appear in this image taken by the European Southern Observatory’s Very Large Telescope Interferometer. Credit: ESO/K. Ohnaka

Antares is a bright star in Scorpius that shines with a strong red tint.  It is a large red supergiant in the later stage of its life and is expected to become a supernova in a few thousand years.  It is located nearly 620 light-years from Earth with a mass and diameter  of 12 times and 700 times that of our sun, respectively.

The team also made the first map of the velocities of material in the atmosphere of a star, other than the Sun, revealing unexpected turbulence in Antares’s extended atmosphere. In stars like our sun, convection flows of superheated gases bubble up from near the stars’ cores to the surface. But convection cannot explain Antares’ strange atmosphere, and the researchers conclude that, for the atmospheres of red supergiants, there must be another—as yet unknown—process that drives the motion of material.  This process might help explain how stars like Antares lose mass so quickly in the final phase of their evolution.

Ohnaka is hopeful that the observational techniques demonstrated on Antares may be applied to other stars to see how their atmospheres are structured, perhaps revealing the mystery that drives these turbulent motions.

The VLTI consists of up to four telescopes—8.2 m “unit” telescopes and smaller 1.8m “auxiliary” telescopes – that combine light using interferometry to create a “virtual” telescope 200 m wide. Very high angular resolution can therefore be attained, allowing the surface of Antares to be studied in detail.