Science with the world’s largest telescopes
Telescopes allow us to explore the universe around us. In the lecture “Science with the world’s largest telescopes” by Katharine Johnston on 10/12/25, this concept was discussed. The lecture explained how telescopes work and provided examples of how large telescopes make universe exploration possible.
Telescopes require large resolutions to gain clear images and to view different aspects of the universe. These resolutions are achieved by building larger telescopes. There are different types of telescopes (e.g. optical and radial) which enable exploration through different means. Optical telescopes collect light in the visible spectrum. This method of collecting information has limitations. For example, as telescopes become larger, the lens also must increase in size. This results in unfocused images due to the lens bending in the middle. Scientists tried to resolve this problem by developing reflective telescopes, which did reduce the impact of the limitations to a certain extent. [1] Radio telescopes, however, use an antenna system. This allows the telescopes to detect radio frequency radiation and use this information to picture its sources, such as stars and galaxies. [2]
With both types of telescopes, the same rule applies: the larger the telescope is, the larger the resolution must be for objects at greater distances. In radio telescopes, the size of the antenna must be proportional to the wavelength to achieve an image with good resolution.
Even if the largest possible telescope were built, it would still face issues with producing a perfect image. This could be caused by inference, such as cosmic dust. Cosmic dust usually consists of tiny chunks of silicone or carbon that interferes with the images by blocking the light. This dust affects the image quality of objects emitting smaller wavelengths more than objects emitting larger wavelengths.
An example of a large telescope is ALMA. IT is made of 66 mobile dishes to make a giant telescope. This was built in the desert in a wide-open space to reduce the amount of water it is looking through as water can absorb some light going through it. The wide-open space allows the fifty-four 12m antennas and the twelve 7m antennas to move and produce different images. The maximum distance between the antennas is up to 16km. [3]
Additionally, another large telescope is the Event Horizon Telescope. It is the largest telescope and combines different telescope facilities across the world to achieve better resolutions. Data is stored on disks and shipped to supercomputers at MIT or to other research labs. This telescope can observe blackholes.
Overall, telescopes such as ALMA and Event Horizon allow a better understanding and clearer images of the universe around us.
[1] “Space Science Reference Guide,” Usra.edu, 2024. https://www.lpi.usra.edu/education/ssrgtextbook/articles/Telescop.htm
[2] K. Kellermann, “Radio telescope | astronomical instrument,” Encyclopedia Britannica, Mar. 08, 2024. https://www.britannica.com/science/radio-telescope
[3] “About ALMA, at first glance | ALMA,” 2021. https://www.almaobservatory.org/en/about-alma/
92913
Feedback based on the mark scheme provided is as follows:
Presentation: Title, name of speaker and date of seminar are provided. Grammar is good. Near the start of the second paragraph, I think there is a typo as it says ‘radial’ rather than radio.
Content: Content mostly accurately covers what was discussed in the seminar, although key points that were discussed in the seminar are not present, such as any mention of Katharine’s own research with ALMA.
Context: Societal context is explained well, but again a real world research example would be good to include, such as Katharine’s research, or more information on the Event Horizon Telescope’s black hole observations.
Style: Some sentences are a bit short and abrupt, otherwise writing style is good and would read well to a lay audience.
External Source: References are correctly labelled, but no quoted opinions are present.
Overall it reads well, the only thing I would say is missing is a larger discussion of a real life application.
90561
Great presentation and tone. Small typo at ‘radial’ (radio) and ‘silicone’ (silicon), but grammar generally good. Good use of external sources and extra info. Could’ve mentioned the black hole images and EHT more but that’s a nitpick from me. Generally very good!
18476
Presentation is good, with good sources and referencing. Would like to see more discussion on its application.