The year 2024 promises to be rich in astronomical events observable in Quebec. A total solar eclipse will darken the sky in spring, and throughout the year, more frequent northern lights will light up our nights.
Early in the afternoon of April 8, those in southern Quebec will have the chance to observe a total solar eclipse. This phenomenon occurs very rarely in our part of the country: the last total eclipse that we were able to observe in Quebec occurred in 1972, and the next will take place in 2106.
On this day, the Moon will pass between the Earth and the Sun and, for a brief moment, the Moon will completely obscure the Sun. We will therefore suddenly be plunged into the shadow of the Moon and we will then have the impression of finding ourselves in the middle of the night.
This spectacular phenomenon requires perfect alignment between the Sun, Moon and Earth. But it also depends on the apparent size of the Moon and the distance between the Earth and the Sun. The closer the Moon is to Earth, the larger it appears to us, thus blocking a larger portion of the Sun during an eclipse. And the further the Sun is from the Earth, the smaller we perceive it – and the more the Moon is then able to completely conceal it.
All of the different phases of the eclipse (partial and total eclipse) will last approximately 2 hours 20 minutes in Quebec, Ontario and New Brunswick.
But the totality phase will be much shorter: it will be 3 minutes 29 seconds at Mont Mégantic, and 45 seconds in Montreal, which is on the edge of the shadow band, where it will occur at 3:26 p.m.
Northern Lights
In 2024, activity on the Sun’s surface will reach its peak in the last 10 years, leading to more flares and ejections of solar material into space. And this intensification of solar activity will have repercussions even on Earth, notably in the form of more frequent and more intense polar auroras.
The Sun is a huge nuclear reactor. In each layer of the solar sphere, different elements merge. The higher the temperature and pressure in a layer, the more relatively heavy elements combine to produce even heavier elements, summarizes Ahmad Hamdan, professor in the Department of Physics at the University of Montreal.
The temperature and pressure being lower on the surface of the Sun than at its center, it is light elements, such as hydrogen, which will fuse into slightly heavier elements, such as helium. “Little by little, the surface of the Sun finds itself enriched in heavy elements which cannot fuse in turn, because the temperature there is not high enough. Melting then decreases, until these heavy elements sink into the underlying layer, which is now lighter. The solar atmosphere then “purifies” and becomes rich in hydrogen again, which allows fusions to resume,” explains the professor.
The mergers that occur on the surface of the Sun follow an 11-year cycle. “The peak of the cycle, which is due to occur in 2024, is when there is more hydrogen than helium and our star burns a lot of hydrogen. The situation is then equivalent to thousands of nuclear reactors in action which cause explosions and the ejection of ionized, that is to say charged, particles into space,” continues the researcher.
However, the core of the Earth, composed largely of iron, acts like a magnet. It generates a large magnetic field which envelops our planet, and which is represented using lines which connect the magnetic North and South poles.
“One of the properties of these magnetic field lines is that they can go to infinity, so very far. They therefore reach the Sun, where they go [attirer] the charged particles that are emitted and confine them around them,” underlines Mr. Hamdan.
Confined around the magnetic field lines, these charged particles then propagate towards the place where the magnetic field is the most intense, namely towards the magnetic poles of the Earth.
When they enter the Earth’s atmosphere, which is denser than the vacuum of space, these charged particles collide with oxygen and nitrogen molecules to which they transfer their kinetic energy by ionizing them. Having become unstable, these molecules then emit photons when they return to a more stable state. These are the photons that we will see at night in the form of the Northern Lights.
The colors that the Northern Lights can take on depend on several factors. The main one is the nature of the gas that the charged particles encounter. When they collide mainly with oxygen molecules, a green color will appear, while if they collide instead with nitrogen molecules, a color ranging from pink to purple will color the sky. The color emitted is also related to the energy level of the charged particles and the amount of energy they transfer to the gas molecules.
In 2024, the Earth’s magnetic field will be even more intense than usual, because more abundant electromagnetic waves emitted by increased solar activity will strengthen it. The magnetic field lines will then retain a greater number of charged particles, resulting in more intense and widespread polar auroras. They will then descend below the poles, allowing them to be observed from southern Quebec.