Excited for the second year of our new Physics with Astrophysics degree program at the University of Lincoln! Right now, I’m fully immersed, working on one of our new modules called “The Solar System and Exoplanets.” We’re diving deep into how planets form and trying to unravel the mystery of the huge variety of exoplanets we keep discovering. Check out this quick video for a taste of what we’re digging into in the module.
The apparent lack of planets with radii 1.5–2 times that of Earth is known as the Sub-Neptune radius valley. First noted in 2011, a bimodality in the Kepler exoplanet population was ascribed to the lack of substantial gas atmospheres on close-in, low-mass planets. It was mentioned that this trait could support the growing theory that atmospheric mass loss could be caused by photoevaporation. This would result in a population of planets with thick envelopes dominated by helium and hydrogen with bigger radii at higher separations from their parent stars, and a population of naked, rocky cores with lower radii at small separations.
Our third-year physics students in the School of Mathematics and Physics went on a field trip to La Palma in the Canary Islands between the 14th and 21st of March 2024.
This field trip is in connection with the module “Physics of the Universe”, which is our third-year astrophysics module, and teaches students about a broad range of topics from exomoons to star formation and the universe.
While on the excursion, the students got to see the Roque de Los Muchachos Observatory, which gets its name from the rocky mound it sits atop. At 2.42 kilometres above sea level, this location is the highest point on the island of La Palma. Because of its high altitude and dry atmosphere, this observatory has one of the greatest collections of professional telescopes in the world. Among these is the GTC (Gran Telescope Canarias), the biggest aperture (10.4m) telescope in the world.
Students got the opportunity to conduct their own astronomical observations under one of the world’s darkest skies in addition to seeing the observatories during the day. Our students saw a variety of celestial objects, including galaxies, star clusters and Orion’s Nebula.
While visiting the Roque de Los Muchachos Observatory we eve got the opportunity to watch the Sunset from above the clouds.
There were plenty of opportunities to tour the island of La Palma, take in some of the local culture in the town of Santa Cruz, visit the neighbouring beach, Plata de los Cancajos, the recent lava flows from the 2021 volcanic eruption, the rainforest to the north east of the island, in addition to setting up telescopes and studying the stars.
Thank you to Ana from La Palma Stars for helping organizing our trips and stargazing during our visit to La Palma: https://lapalmastars.com/en/
Astronomers can state the mass of the Earth, the planets and moons, the Sun and stars, giant black holes, galaxies, and even the whole universe. How do we know that? How do we weigh a planet, star, black hole, galaxy, or even the universe? And what about the mysterious dark matter and dark energy? Come find out!
This is our 17th Astro-Chat with our distinguished guest Professor Don Kurtz. The session will include a brief illustrated introduction followed by questions and answers. Members of the public will be able to ask questions in the live-chat. The event is hosted by Professor Andrei Zvelindovsky, Head of the School of Maths & Physics at the University of Lincoln, UK.
The School of Mathematis adn Physics at the University of Lincoln has a New post open for Lecturer in Astrophysics. For full details see the following job advert:
The University of Lincoln opened the School of Mathematics and Physics in September 2014 as part of the College of Science. The school provides undergraduate and postgraduate education and conducts research in pure and applied mathematics, physics and astrophysics. The school is expanding its provision and is opening a new undergraduate Physics with Astrophysics degree from September 2023.
We are now seeking suitably qualified applicants for the post of Lecturer in Astrophysics to join our Astrophysics team.
The post holder will be expected to develop their own research and we are considering applicants with research interests in any aspect of astrophysics. Our successful candidate will be passionate about teaching and outreach, and will be prepared to deliver teaching in a range of modules offered by the school, including the Astrophysics modules of the new degree. The post holder will join a friendly community at the School of Mathematics and Physics and be part of our rising University, located at the heart of the historic city of Lincoln.
We are especially encouraging applications from groups underrepresented in STEM. Candidates with a career break are also encouraged to apply.
The University of Lincoln offers exciting career opportunities with the chance to grow and develop to reach your full potential. We also offer a wide range of staff benefits, including a generous annual leave allowance, progressive pay rates, access to discounts at popular stores and more. If you will need to relocate to Lincoln from within the UK or internationally for this opportunity, we understand how difficult this can be. We have dedicated support in place to make the process as simple for you as possible.
During 23rd – 30th March 2023 the third year physics students in the School of Mathematics and Physics went on a field trip to La Palma in the Canary islands. the field trip links with the module “Physics of the Universe” and gives students a chance to visit the Roque de Los Muchachos Observatory, which house one of the largest collections of professional telescopes in the world. This includes the largest aperture (10.4m) telescope in the world, the GTC (Gran Telescope Canarias).
As well as visiting the observatories during the day students also had the chance to do their own astronomical observations and experience some of the darkest skies in the world.
There was also some free time during the week to enjoy the beautiful scenary the island has to offer.
Below is an article we wrote on The Conversation about our work on the formation of continents on the Early Earth and the movement through the Milkyway galaxy:
“To see a world in a grain of sand”, the opening sentence of the poem by William Blake, is an oft-used phrase that also captures some of what geologists do.
We observe the composition of mineral grains, smaller than the width of a human hair. Then, we extrapolate the chemical processes they suggest to ponder the construction of our planet itself.
Now, we’ve taken that minute attention to new heights, connecting tiny grains to Earth’s place in the galactic environment.
Looking out to the universe
At an even larger scale, astrophysicists seek to understand the universe and our place in it. They use laws of physics to develop models that describe the orbits of astronomical objects.
Although we may think of the planet’s surface as something shaped by processes entirely within Earth itself, our planet has undoubtedly felt the effects of its cosmic environment. This includes periodic changes in Earth’s orbit, variations in the Sun’s output, gamma ray bursts, and of course meteorite impacts.
Just looking at the Moon and its pockmarked surface should remind us of that, given Earth is more than 80 times more massive than its grey satellite. In fact, recent work has pointed to the importance of meteorite impacts in the production of continental crust on Earth, helping to form buoyant “seeds” that floated on the outermost layer of our planet in its youth.
We and our international team of colleagues have now identified a rhythm in the production of this early continental crust, and the tempo points to a truly grand driving mechanism. This work has just been published in the journal Geology.
Residing inside the Milky Way galaxy makes it impossible to picture, but our galaxy is thought to be similar to other barred spiral galaxies, like NGC 4394. ESA/Hubble & NASA
Many rocks on Earth form from molten or semi-molten magma. This magma is derived either directly from the mantle – the predominantly solid but slowly flowing layer below the planet’s crust – or from recooking even older bits of pre-existing crust. As liquid magma cools, it eventually freezes into solid rock.
Through this cooling process of magma crystallisation, mineral grains grow and can trap elements such as uranium that decay over time and produce a sort of stopwatch, recording their age. Not only that, but crystals can also trap other elements that track the composition of their parental magma, like how a surname might track a person’s family.
With these two pieces of information – age and composition – we can then reconstruct a timeline of crust production. Then, we can decode its main frequencies, using the mathematical wizardry of the Fourier transform. This tool basically decodes the frequency of events, much like unscrambling ingredients that have gone into the blender for a cake.
Our results from this approach suggest an approximate 200-million-year rhythm to crust production on the early Earth.
But there is another process with a similar rhythm. Our Solar System and the four spiral arms of the Milky Way are both spinning around the supermassive black hole at the galaxy’s centre, yet they are moving at different speeds.
The spiral arms orbit at 210 kilometres per second, while the Sun is speeding along at 240km per second, meaning our Solar System is surfing into and out of the galaxy’s arms. You can think of the spiral arms as dense regions that slow the passage of stars much like a traffic jam, which only clears further down the road (or through the arm).
Geological events, including major crust formation events highlighted on the transit of the Solar System through the galactic spiral arms. NASA/JPL-Caltech/ESO/R. Hurt (background image)
This model results in approximately 200 million years between each entry our Solar System makes into a spiral arm of the galaxy.
So, there seems to be a possible connection between the timing of crust production on Earth and the length of time it takes to orbit the galactic spiral arms – but why?
Strikes from the cloud
In the distant reaches of our Solar System, a cloud of icy rocky debris named the Oort cloud is thought to orbit our Sun.
As the Solar System periodically moves into a spiral arm, interaction between it and the Oort cloud is proposed to dislodge material from the cloud, sending it closer to the inner Solar System. Some of this material may even strike Earth.
Milky Way’s structure and Solar System’s orbit through it may be important in controlling the frequency of some large impacts on Earth, which in turn may have seeded crust production on the early Earth. jivacore/Shutterstock
Earth experiences relatively frequent impacts from the rocky bodies of the asteroid belt, which on average arrive at speeds of 15km per second. But comets ejected from the Oort cloud arrive much faster, on average 52km per second.
We argue it is these periodic high-energy impacts that are tracked by the record of crust production preserved in tiny mineral grains. Comet impacts excavate huge volumes of Earth’s surface, leading to decompression melting of the mantle, not too dissimilar from popping a cork on a bottle of fizz.
This molten rock, enriched in light elements such as silicon, aluminium, sodium and potassium, effectively floats on the denser mantle. While there are many other ways to generate continental crust, it’s likely that impacting on our early planet formed buoyant seeds of crust. Magma produced from later geological processes would adhere to those early seeds.
Harbingers of doom, or gardeners for terrestrial life?
Continental crust is vital in most of Earth’s natural cycles – it interacts with water and oxygen, forming new weathered products, hosting most metals and biological carbon.
Large meteorite impacts are cataclysmic events that can obliterate life. Yet, impacts may very well have been key to the development of the continental crust we live on.
However we came to be here, it is awe-inspiring on a clear night to look up at the sky and see the stars and the structure they trace, and then look down at your feet and feel the mineral grains, rock and continental crust below – all linked through a very grand rhythm indeed.
Lincoln Astrophysics Team 