Zoom link (Meeting ID: 850 1103 3763 Passcode: 653518)

We believe that the first stars in the universe formed about 200 million years after the Big Bang. Yet, we lack solid observational evidence about the timing of this epoch, called Cosmic Dawn.

The experiment SCI-HI is searching for the first stars at Cosmic Dawn by the detection of variations in the 21 cm Hydrogen line background as a function of cosmic time. Towards achieving our goal, we have sought radio quiet zones within Mexican Territory and have identified Isla Guadalupe in the Mexican Pacific Ocean 300 km off the Baja California Peninsula, as one of the best radio quiet zones in North America.

In this talk, Dr. López-Cruz will present the first SCI-HI results, some current improvements, and perspectives.

ABOUT OUR SPEAKER:

Dr. Omar López-Cruz is a Mexican Astronomer (M.Sc. & Ph.D.; Department of Astronomy, University of Toronto) who has worked on stellar classification and the evolution of galaxies in large density environments.

In 2014, he led an international team that proposed the cD galaxy Holm 15A as the host of the largest supermassive black hole (SMBH) in the local universe. In 2019, a German team led by Kianusch Mehrgan measured a mass of 40 billion times the mass of the Sun in Holm 15A, confirming the López-Cruz et al. conjecture. He also likes the popularization of Science. Recently he became the co-director of a book collection called La Biblioteca Científica del Ciudadano (The Citizen’s Scientific Library) aimed at encouraging the debate of scientific ideas in democratic societies. He appears on radio programs regularly and lectures widely on Astronomy and Scientific Affairs. He writes for magazines and newspapers in Mexico.

Zoom link (Meeting ID: 850 1103 3763 Passcode: 653518)

Zoom link: Meeting ID: 826 0823 4950 , Passcode: 212094

Supernovae are among the most violent events in the Universe since the Big Bang. They are highly destructive. And yet, they are also largely responsible for creating and dispersing most of the elements that enrich the Universe we live in. Indeed, without supernovae, the Earth and Life as we know them would likely not exist. On February 24, 1987, the brightest supernova since the invention of the telescope was discovered by a Canadian astronomer working on a mountaintop in Chile.

Join Dr. Ian Shelton for a personal account of his discovery of Supernova 1987A and efforts to find the elusive neutron star “beast” that created the explosion.

Zoom link: Meeting ID: 826 0823 4950 , Passcode: 212094

With heavy hearts, we report the passing of Professor Emeritus Tom Bolton earlier this week.

Tom is probably best known for providing the first definitive evidence showing that Cygnus X-1 is a black hole using the David Dunlap Observatory’s telescope. He was also instrumental in drafting the City of Richmond Hill’s landmark light pollution abatement bylaw.

As a close colleague of ours, he will dearly be missed.

Please take the time to watch this TVO Science Café episode where Tom -alongside other notable DDO astronomers – explains the history of the DDO and provides a tour of the 74″ telescope (circa 1990).

-DDO Defenders

If you would like to follow the exciting Astronomical Events in December,  please register to our upcoming Virtual Up In the Sky DDO program. Our expert astronomers will be teaching you how to navigate the night time sky.

Please visit richmondhill.ca/astronomy to register and get more information about this program.

On December 21st Jupiter and Saturn will pass very close to each other, so close that you’ll need binoculars or a telescope to separate them. During the month of December these two gas giant planets can be seen just after sunset can be seen just above the south-west horizon. The attached video (animated GIF) shows how the two planets move each day during the month of December, then move apart after their closest approach on the 21st. Even if the weather doesn’t cooperate on the day of closest approach, it will be a fun sight to watch these two giant planets move each clear evening during the month of December.

-DDO Defenders 🙂

Every couple of years, Earth passes near to Mars. But because Mars’ orbit is quite elongated (“elliptical”), the distance between the two planets can get much closer every 15-17 years. This year was one of these closest approach years, with Mars just 62 million km away on October 6^th. Ok, not close enough to ever worry about ever hitting Mars; but if you are in the business of sending spacecraft to other world, this is the best time to do so. And indeed, the US, China and the United Arab Emirates each launched their own mission to Mars this year, all expected to arrive there in February next year.  

Both planets, of course, are continuing to travel along their respective orbits about the Sun. As the Earth moves faster along its smaller inner orbit closer to the Sun, it overtakes Mars travelling in its more distant orbit, like race cars travelling along an oval racetrack. From our perspective here on Earth, as Earth overtakes Mars, Mars will be seen in the opposite direction from the Sun. Hence, we use the term “opposition” to describe these events. And if Mars is currently opposite the Sun, that means it rises in the East at sunset and will spend the whole night crossing the sky to set in the West at sunrise!   Mars continues to appear to the unaided eye as an unusually bright, orangey coloured “star” in the Eastern sky after sunset until the end of October. It will then begin to fade noticeably as the distance between the two planets steadily increases. Although it will rise earlier each night and stays high in the sky through the night, it will have dropped five-fold in brightness by Christmas time. So enjoy Mars now while it’s at its best! If you have a telescope, even a small telescope, this is your best opportunity to see Mars through your scope for the next 15 years!!! Here’s a sample of what our members have been able to achieve in 2020… 

-DDO Defenders 😁

The Orionids meteor shower peaks on the night of Tuesday October 20-21. This is a modest shower, producing about 20 meteors (“shooting stars”) per hour if you are viewing away from city light pollution. Of course, the sky needs to be clear. And expect to see less than half that number if you are observing from a moderately dark backyard in the suburbs. The crescent moon sets at around 9:30 pm on this night and so won’t spoil the view this year.  

It takes at least 15 minutes for your eyes to fully adjust to the dark so you can see the fainter meteors (…there are many more fainter meteors than bright ones). Turn off all yard lights and find a place that is shielded from seeing your neighbour’s lights or streetlights. Even looking at your phone’s display can cause you to lose your dark adaption and you will need another 15+ minutes in the dark to restore it. 

You will need to wait till about 10:30 pm EDT before any of these meteors will become visible. That is when the “radiant” for this shower rises above the Eastern horizon. If the sky is clear and you do indeed start your viewing right at 10:30 (till ~11:00 pm), you have a chance to catch an impressive “earth-skimmer” meteor, one that remains visible for a longer time as it streaks across a much longer path across the sky. 

To watch the Orionids or any other meteor shower, I strongly recommend you find yourself a fully reclining full length deck chair (Chaise Lounge) so you can be off of the ground and comfortably looking straight overhead without having to bend your neck. That is where you want to be looking, straight overhead to see the most meteors. The meteors will seem to be coming from a particular point in the sky, the shower’s “radiant”: whichever constellation the radiant lies in is how a meteor shower gets its name. In this case, the radiant lies in the constellation of Orion. But each meteor can be almost anywhere in the sky when it first lights up; and then it usually travels less than a quarter of the distance from horizon to horizon before it stops glowing.  

For those interested in knowing what an Orionid meteor is made of, you might be surprised to learn they are pieces of Comet Halley, which last passed by the Earth in 1986. Comets leave behind a trail of rock dust that fills the path they take as they orbit the Sun. Earth passes through that thin debris trail twice each year, producing the Orionid meteor shower in the Fall and the Eta Aquarids meteor shower in early May. 

-DDO Defenders 😄