Science Show Summer - The Extremely Large Telescope
The Science Show
Deep Dive
Why is the Extremely Large Telescope (ELT) being built in the Atacama Desert?
The Atacama Desert is one of the driest places on Earth, offering exceptional atmospheric conditions with over 300 clear nights per year and very low turbulence. Its high altitude and isolation from light pollution make it ideal for astronomical observations, especially in the infrared spectrum.
What makes the ELT's mirror unique compared to other telescopes?
The ELT's main mirror is 39 meters in diameter, making it the largest optical telescope mirror ever built. It consists of 798 hexagonal segments, each with 12 edge sensors and three pistons for precise adjustments. This design compensates for warping under gravity and ensures high-resolution imaging.
How does the ELT's adaptive optics system work?
The ELT uses laser beams to create artificial stars in the upper atmosphere. The twinkling of these stars is measured in real-time, and the data is used to adjust the shape of the telescope's mirror via tiny electronic pistons. This system cancels out atmospheric distortion, providing clear images almost as if the telescope were in space.
What are the main scientific goals of the ELT?
The ELT aims to study the first galaxies and stars formed over 13 billion years ago, detect Earth-like planets in habitable zones around other stars, and analyze their atmospheres for signs of life, such as oxygen, water, or industrial pollutants. It will also provide sharper and more detailed images than any existing telescope.
How does the ELT compare to the James Webb Space Telescope?
The ELT collects 40 times more light than the James Webb Space Telescope and can produce images five to six times sharper. While James Webb has a finite lifespan, the ELT is expected to operate for at least 50 years, with the ability to upgrade its instruments over time.
What challenges does the ELT face in its construction?
The ELT must withstand extreme environmental conditions, including high winds, earthquakes, and low humidity. Its massive structure, weighing 6,100 tonnes, rotates on a hydrostatic bearing system with precision measured in millionths of a degree. Each mirror segment must also be meticulously cleaned and assembled to avoid errors.
Why is Australia considering joining the European Southern Observatory (ESO)?
Australia lacks the high, cloudless terrain needed for next-generation telescopes like the ELT. Joining ESO would grant Australian astronomers access to the ELT and other ESO facilities, ensuring they remain competitive in optical and infrared astronomy. However, full membership requires a $400 million investment over 10 years.
What is the significance of the ELT's first scientific observations planned for 2028?
The ELT's first observations will mark the beginning of a new era in astronomy, enabling unprecedented studies of distant galaxies, exoplanets, and the early universe. Its advanced capabilities are expected to revolutionize our understanding of cosmic phenomena and potentially discover signs of extraterrestrial life.
How does the ELT's size and precision compare to other proposed giant telescopes?
The ELT is the largest and most advanced of the proposed 30-40 meter class telescopes, with a 39-meter mirror. It is ahead of the Giant Magellan Telescope (25 meters) and the Thirty Meter Telescope, both of which face funding and logistical challenges. The ELT is on track to be the first operational giant telescope of its kind.
What role does Chile play in the ELT project?
Chile hosts the ELT due to its exceptional astronomical conditions. As the host nation, Chilean astronomers are allocated 10% of the telescope's operating hours, fostering local scientific growth. The project also collaborates with Chilean communities, though tensions with Indigenous groups over land use remain a consideration.
- Arrival in the Atacama Desert and initial observations of the ELT site.
- Description of Paranal Observatory and its facilities.
- Challenges of water supply and light pollution control in the desert.
- Introduction of the Very Large Telescope (VLT) and its accomplishments.