UBC Physicists recently proposed fluctuating space-time in a theory for dark energy that unifies general relativity and quantum mechanics. PhD students Qingdi Wang and Zhen Zhu along with professor Bill Unruh published their research in Physical Review Dlast week. You can also find out more by listening to an interview with Jaymie Matthews that aired on CBC Vancouver’s The Early Edition:
The work suggests that, at very small scales, the universe is constantly fluctuating between expansion and contraction. The fluctuations almost cancel each other but a small net effect is responsible for the “dark energy” that is causing the universe to expand at an accelerating rate.
Previous models of dark energy using quantum mechanics and relativity were not compatible. Models using quantum mechanics theorized that dark energy must be incredibly dense, but relativity predicted that the universe would explode with such dense dark energy. This new research resolves the incompatibility between the two models.
One of the most inspiring sights is standing under a dark sky with the night sky ablaze with stars. Today, this inspiration is diminished by ever-increasing light pollution. Energy efficient LED street lights, being installed by cities across Canada, can make things worse. Further, as Halifax and other cities have discovered: the residents often hate LED street lights.
An episode of The Current on CBC radio documents a complaint from a resident of Halifax who said the whiteness of the light keeps her whole family up at night – even her cat, Coco. Other cities have faced similar complaints and more: LED street lights have been blamed for stealing the romance of Rome, ruining nighttime film production in Los Angeles, and disorienting salmon in the Sacramento River.
The American Medical Association’s (AMA) research concludes that LED street lights that are too blue or white can suppress melatonin, affect our sleep, and lead to obesity. Other studies indicate an increased risk for certain cancers.
LED lighting is an amazing technology, and while LED street lights are costly to install, the new lights promise to last for decades, be maintenance-free, and cost considerably less to operate.
Colour is a major obstacle for LED lighting. The most cost-effective LEDs emit a much bluer light than the sodium vapour lamps that are traditionally used. Blue-rich LED lights increases the amount of glare sensed by the human eye and also the amount of visible light pollution. This occurs because blue light scatters more through the atmosphere than red light.
The colour for lighting is measured by a unit of temperature known as kelvins. The higher the kelvins the whiter the light. Light with a temperature between 2,000 and 3,000 kelvins is a warm white that’s comfortable, like the older lights. Light from LEDs with a temperature over 5,000 is extremely harsh: they’ve been called “zombie lamps” in Seattle and “prison lamps” in Oceanside, California.
Hopefully, cities in Canada and elsewhere will follow the AMA’s guidance on LED street lighting that includes several recommendations to help reduce light pollution.
The AMA recommends an intensity threshold for optimal LED lighting that minimizes blue-rich light (less than 3000 kelvins).
The AMA also recommends all LED lighting should be properly shielded to minimize glare.
Consideration should be given to utilize the ability of LED lighting to be dimmed for off-peak time periods.
For more information:
Visit our table on light pollution that is part of Science Rendezvous and Astronomy Day on May 13th, 2017 at Simon Fraser University.
This evening the Moon and Jupiter are less that five degrees apart, close enough to fit together within the same binocular field. The pair are closest when Jupiter rises in the east at about 5:30 pm then drift apart as the night progresses. The Moon-Jupiter combo will be an obvious naked-eye sight in the south-east by 9:00 pm.
Jupiter crosses the Meridian at 11:00pm, at which time it will be due south and at its highest point above the horizon. The Galilean moons – Io, Europa, Ganymede, and Callisto – will be visible in small telescopes or even binoculars. Jupiter’s Great Red Spot will also start to become visible through a telescope around 11:00pm.
Galileo Galilei discovered Jupiter’s moons in January 1610 and realized they were satellites of Jupiter in March 1610. This was a revolutionary discovery as they were the first objects found to orbit another planet.
Dr. Lynda Spilker talked about Going out in a Blaze of Glory: Cassini Science Highlights and the Grand Finaleat our Paul Sykes Memorial Lecture back in January of this year. More remarkable discovers from Cassini are expected when it repeatedly dives between the innermost ring and the top of Saturn’s atmosphere during its final six months starting this week. The first of the spaceship’s 22 deep, daring dives is scheduled for April 26 at 2:00am PDT.
When Cassini passed close by Titan on April 22, the moon’s gravity pulled strongly on the spacecraft. The flyby gave Cassini a change in velocity of about 800 meters per second that started the spacecraft on its first of the ring-gap orbits.
A grand finale dive will plunge Cassini into Saturn’s atmosphere on September 15th, vaporizing the spacecraft to protect tiny Enceladus, one of Saturn’s ocean worlds, from hardy Earth-based microbes that may have stowed-away on Cassini.
The Cassini mission’s findings have revolutionized our understanding of Saturn, its complex rings, the amazing assortment of moons and the planet’s dynamic magnetic environment. The robotic spacecraft arrived in 2004 after a 7-year flight from Earth, dropped a parachuted probe named Huygens to study the atmosphere and surface of Saturn’s big moon Titan. Some of the mission highlights include:
Astronomy Day is celebrated in conjunction with SFU’s Science Rendezvous. Come join us on Saturday, May 13th from 11am to 3pm in the East Concourse of the Academic Quadrangle (see map) and at the Trottier Observatory. There will be activities and short lectures throughout the day.
Budding youth astronomers can get a free ticket in a draw for a new telescope provided by Sky-Watcher Telescopes.
Apollo Rockets and Mission display
Jim Bernath and his hands-on science activities
Light pollution display
Solar system and our planets display
Solar telescope display and observing (weather permitting)
11:00-11:30, What’s new in the search for exo-planets and extra-terrestrial life by Stanley Greenspoon
12:00-12:30, The Moon 101 by Ted Stroman 1:00-1:30, Proxima_ b: The planet next door by Robin Adams 2:00-2:30, Tales from the Russian Space Program by Scott McGillivray
A beautiful documentary film about western Canada’s dark sky parks, and star parties: Ambassadors of the Sky by Brandy Y Productions. It will be aired every hour on the hour.
New Telescope Draw
A special prize for a budding young astronomer. A brand new Telescope provided by Sky-Watcher Telescopes. Tickets are free to youth from 6 to 18 years of age. A draw will occur at the end of the event and the winner notified.
“Circling the Earth in my orbital spaceship I marveled at the beauty of our planet. People of the world, let us safeguard and enhance this beauty — not destroy it!”
— Yuri Gagarin, 1st human in space.
RASC Vancouver has organized a Yuri’s night meetup event to celebrate humanity’s past, present, and future in space. Yuri’s Night parties and events are held around the world every April in commemoration of Yuri Gagarin becoming the first human to venture into space on April 12, 1961, and the inaugural launch of the first Space Shuttle on April 12, 1981.
Yuri’s Night at La Fontana Cafe
Saturday, April 22nd, 2017 6:30pm-11:00pm
La Fontana Cafe
101-3701 Hastings Street, Burnaby, BC (map)
RSVP on the Meetup Event: still some spots available as of 2:30pm on April 22nd.
RASC’s own Scott MacGillivray of Global TV’s “Space Talk with Scott” will be presenting on humanities first endeavours into space travel. (at approx 8:00 pm).