An introduction to Astronomy: exploring the wonders of our Universe

A Certificate of Participation is awarded to participants who contribute constructively to weekly discussions and exercises/learning activities for the duration of the course.

This tutor-led, cohort-based online course is 7-weeks in duration and is made up of 5 teaching units.

Week 1 - The solar system - the search for life

Purpose: Our solar system may be unique, both in its configuration and as a source of life. We shall study the configuration of our own solar system, to better understand those around other stars, and understand what makes our planet such a hospitable place for life. We will focus on our attempts to search for life within this system, which if chemically different from ours, then we'd know it evolved independently from us, and most importantly, we'd know life had begun more than once.

Learning outcomes:

• A deeper understanding of the quickly evolving field of planetary science, not just of those with worlds within our own planetary system, but the rapidly increasing number around other stars.

• An overview of the current state of knowledge regarding each planet within the solar system, using the latest observations from such missions as Cassini–Huygens or New Horizons, in regards to their behaviour, properties and motions, in particular their geophysical  history.

• Explored the full extent of the solar system from Mercury to the Oort cloud, defining its outer limits, and understand the origin and evolution of our planetary system.

• Met the concept of gravitational bending and the first major test of the theory of general relativity.

• Understood the meaning of habitable worlds, the search for liquid water and hence why the most likely places to find life in the solar system include Europa (Jupiter) and Enceladus (Saturn).

• Understood why Mars has proved so fascinating in our search for life, as it may have harboured life in a long lost congenial past.

• From a sense of scale of our solar system come to appreciate both the difficulties in traversing and colonising the solar system, and why the Earth is so special.

Week 2 - Exoplanets

Purpose: It has been compared with looking for a firefly next to a searchlight, but we shall study the detection methods used to look for exoplanets,  which only existed in hypothesis until 1992, of which we now know that our galaxy is likely to contain trillions. However, exoplanetary solar systems look nothing like our own, and this had an impact on our planetary systems formation models. We will also outline our continued search for life in these systems and the efforts to directly image them.

Learning outcomes:

• To have understood when and how, using both the radial velocity and transit methods, exoplanets were discovered, leading to the present torrent of new discoveries, currently standing around about 4000 exoplanets.

• To discuss the habitability of recently discovered exoplanets, in particular those around red dwarf stars.

• To compare other planetary systems with our own, and understanding the apparent uniqueness of our own solar system, which has altered our understanding of how its present structure originated.

• To reviewed the search for life in other solar systems as we observe exoplanet atmospheres, and the current efforts to undertake the difficult task of directly imaging exoplanets.

• To understand the importance of the latest mission, such as TESS, locating planets close to home for easier study and in particular whether their surfaces are hospitable for life, and future missions, such as JWT, to study planetary atmospheres.

Week 3 - Stars

Purpose: Our galaxy is full of stars of many sizes and colours, such that stars span a range about a factor of a thousand in mass, a factor of a million in size, and a factor of a billion in power. The Sun is one such star, providing the closest laboratory for studying a star, from which we can understand how stars actually shine. With this understanding we'll see how stars are born and die, such that 97% of all stars end their existence as white-dwarfs, while for the massive stars, dying in the blaze of glory of a supernova, is more the exception.

Learning outcomes:

• To have understood the properties of our nearest star, the Sun, to comprehend its very dynamic and active nature, through recent missions such as SDO and Parker, and its effect on surrounding planets through the energetic solar wind and flares.

• To learn from stellar observations how we discerned the source of energy in stars, the nuclear fusion process and our attempts to replicate it, with all its associated difficulties, here on Earth.

• To have comprehended the current state of hydrostatic equilibrium in which our sun exists, and its implications for its future history.

• To analyse the H-R diagram of luminosity against temperature from observations of many different stars, and learned how this led to a full understanding of the evolutionary history of stars through their life-cycle from birth to death.

• To follow the birth of a proto-star in a stellar nursery, linked this to evolving fusion history of the star and its eventual fate based on the mass of the star itself.

• To apply this understanding to the future history of our own Sun, and the consequences for our own planet, the Earth.

• To cecome aware that the end for the vast majority stars, including our Sun, is the white dwarf stage, while for the remaining few that meet cataclysmic ends, this includes such dangerous outcomes as supernova and black holes.

• To have discussed the differences between nova, supernova and hypernova.

• To have comprehended the importance of supernovas to life in the universe, and how without them we would not be here.

Week 4 - Milky Way

Purpose: We'll investigate the size, structure and constituent parts of our island universe, the Milky Way, and see how we determine both the Sun's galactic location and the galaxies spiral nature, while located deeply within it. Then we'll look at the sleeping monster at its heart, found possibly in all galaxies, located at the galactic centre, Sagittarius A star, and its recent attempt to grab a meal. By creating an accurate 3D-map of our quadrant of the Galaxy, allows us to study its history and evolution. We'll conclude with a look at this current period, the Age of Stars, a season for life due to the abundant stellar heat and light, which now appears to be in its very latter stages.

Learning outcomes:

• To cover the structure and properties of the Milky Way, such as its size and shape, and how that changes when observed in a variety of different wavelengths.

• To comprehend the relative importance of various components that make up our galaxy, from dark matter, that forms the halo within which the visible galaxy is embedded, to stars that compose the disk and halo, gas, from which stars are formed, and dust which obscures our view through the galaxy itself. 

• To look at how we determine size and shape of the Milky Way from our position with it, through the observations of globular clusters that orbit the centre of our galaxy, and the emissions of gas that reveal its distribution in the form of arms.

• To consider the different populations of stars within the galaxy, the zone of obscuration which limits our view of the heart of our galaxy, and the giant molecular clouds which are the birth sites of stars.

• To understand how observations of centre of our galaxy have revealed the hidden supermassive black hole (SMBH) at the heart of the galaxy, similar to that possibly in all galaxies, and its close relationship with the evolutionary history of our galaxy despite the vast discrepancy in size between the two.

• To cover the relatively recent attempt by the SMBH to eat a nearby passing gas cloud, and the attempt to directly image it using the Event Horizon Telescope.

• To learn how we are making a 3-D map or our galaxy quadrant, deciphering its evolutionary history through the Gaia mission, as the galaxy has grown by cannibalizing other smaller galaxies over time, and improving the accuracy of the HR diagram, and hence our understanding of the evolution of stars.

• To understand that the present age of stars, the present phase in the evolutionary life of the universe, and how it’s coming to end, and its implications for the future history of life.

Week 5 - Dark Matter

Purpose: 85% of all matter in the cosmos is of unknown origin, but despite that there's not inconsiderable evidence, going back to the 1930s, to show that it's real, and without it galaxies would fly-apart. Dark matter is an intrinsic part of the currently accepted paradigm for the origin and evolution of the universe, the Lambda-CDM model, and has sculptured the structure we observe in the cosmos, which would never have formed in the current time-scale of the universe without its presence. Detecting dark matter particles is a major goal, and would take physics beyond the standard model of particle physics, as the most likely explanation is a particle of unknown nature.

Learning outcomes:

•To consider the long history, beginning in 1932, from Oort to Rubin, for the evidence of dark matter, and how observations of galaxies and galaxies clusters, through the study of velocity distributions, have required dark matter to exist if such objects are to persist.

• To review further supporting evidence provided through observations of the Cosmic Microwave Background (CMB), most directly through observations of galaxy cluster collisions using the technique of gravitational lensing, and modelling of timescales for the emergence of large-scale structure in the universe, which would be too short without the helping hand of dark matter.

• In considering the nature of dark matter understand why MACHOs have been ruled out as a possible contender, and the present chase for WIMPs through various detection experiments that are presently underway, deep in underground mines and at the LHC.

• To look at how dark matter may be distributed in a galaxy, the present discrepancy between models and observations, and the possible explanations to account for it.