[3rd Zoom session with Dr. Sharon Morsink ] Approaching a Black Hole and Crossing the Event Horizon

Join our third Zoom session starting at 2022-01-21T15:00:00Z.

(Feel free to join us 30 minutes earlier to chat and set up your Zoom before we start the session!)

In this meeting, we’ll be interacting with the Instructor of the course Astro 101 Professor Sharon Morsink .

Prof. Sharon Morsink graduated with an Honours Physics BSc from the University of Waterloo, and a PhD in Theoretical Physics from the University of Alberta. Her theses (both for BSc and PhD) were on theoretical aspects of black holes. After graduation, she worked at the University Wisconsin-Milwaukee as a Postdoctoral Researcher and also taught her first course, first-year astronomy. After 3 years, she moved back to Edmonton Alberta and started a position as a professor. Over the years she has taught courses on many areas of physics and astronomy and has also conducted research on neutron stars and black holes.

She will be joining us in a question and answer type session so don’t miss this opportunity!

See you there, bye!


Recording: here.

@sonal Newtonian gravity is not a relativistic theory, it is based on Newtonian mechanics, and therefore also fails at high speeds. Note that even at low velocities, Newtonian gravity also fails when very strong gravity is involved and when the gravitational field is time-dependent.

@Fabio Galilean invariance - Wikipedia

@hhliu It’s curious to me, how this is being crazy led to a rewriting of physics, but Schroedinger’s cat’s similarly crazy prediction is now accepted as true (Superposition)

@Fabio Why the speed of light is this fundamental/universal constant in the universe? Is it related to how our universe was formed or there was no other way to have it differently?

@hhliu Fabio, I recommend Stephen Hawking’s book The Grand Design. He goes into that.
Different bubble universes created with different “fundamental constants”


Ground teams plan to fire Webb’s thrusters at 2 p.m. Monday, Jan. 24 to insert the space telescope into orbit around the Sun at the second Lagrange point, or L2, its intended destination, nearly 1 million miles from Earth.

@sonal Isn’t L2 at the end of our solar system?

@Mervyn Sonal, I don’t think so. It’s probably near mars’


@hhliu @Mervyn @Sonal I think you can have L1,2,3 etc points for different two-body systems, so you can talk about the L2 point of the Sun-Earth system, or the L2 point of the Earth-Moon system, for example:

There are five such points, labelled L1 to L5, all in the orbital plane of the two large bodies, for each given combination of two orbital bodies. For instance, there are five Lagrangian points L1 to L5 for the Sun–Earth system, and in a similar way there are five different Lagrangian points for the Earth–Moon system.

@Mervyn Haihao, yeah I imagine people fighting over these 5L points in the future

@sloopie72 How “big” is the L2 spot? Is it literally a point? Is there room for something else to coexist along with the JWST, or would it have to be so close together the risk of collision would be too great?

@hhliu It’s a point. And only 4 and 5 are stable equilibria, as in for the other ones, small deviations in an object at those points will fling them away, so correction rockets are needed to stay in orbit there.

@Fabio Professor Sharon is part of this project:

@tanyagarg2606075 In case of JWST why do the extra million kilometers make a difference in observation of far-away black holes, considering that the universe is much much more vast than that? Is it not like comparing a mm to hundreds of km?

@Fabio So, it’s not about distance. It’s about “pollution” and interference from Earth

@Shambhavi How is density high and pressure low right before the formation of a star? I can’t wrap my head around it.

  • But molecular clouds are at 10-30K (cold) so doesn’t gas cool down

@romanmoryachk1200881 Are there any observational confirmations of presence of both the rotating and non-rotating BH?

@Fabio Crowdsourcing astronomy project: Zooniverse

That's it for today! Thanks
1 Like

It was really a great session today! The professor is so enthusiastic and connected well with the cohort members. Everyone asked great questions! I also loved her presentation…simple and thought-provoking…very interesting…!

forgot to take a picture with the professor!