Astronomy has a bright future.
The universe is being revealed in exquisite detail with the current generation of large optical telescopes, dating back to close to the big bang. There is hope that the mysteries of dark matter It is dark energy will be resolved. Thousands of exoplanets have been discovered, and astronomers may be getting closer to the first detection of life beyond Earth.
However, observations of the cosmic frontier involve extremely faint targets, and astronomers are always hungry for more light. To continue peering into unknown regions of the Universe, the next generation of giant telescopes on the ground and in orbit will each cost billions of dollars. That price is leading to a collision between scientific aspirations and fiscal realities.
Related: The 10 largest telescopes on Earth
The cost of large glass
For most of the history of astronomy until 1980, there was a rough estimate scaling telescope cost with mirror diameter, where the cost was equal to the diameter of the telescope multiplied by the power of 2.8. This meant that if the size doubled, the cost would increase by a factor of seven – and if the size tripled, the cost would increase by a factor of twenty-two. Many people doubted that a telescope larger than the Palomar 5 meters someday it would be built.
Over the past four decades, however, telescope costs have increased at a slower rate with size, breaking the previous cost curve. O innovations What led to this change were thinner, lighter mirrors, the practice of making a large collecting area from a mosaic of smaller mirrors, using fast optics to allow for more compact telescope designs and decrease the size of telescope cases. Thanks to these innovations, sixteen telescopes with diameters between 6 meters and 12 meters were built between 1993 and 2006.
The search for gigantic telescopes
The next generation of extremely large telescopes will have 100 times the light-gathering power and 10 times the image quality of the Hubble Space Telescope. However, they are facing serious financing problems. There are two American-led projects with international partners. O Thirty meter telescope (TMT) uses a design with 492 mirror segments. Faces headwinds from opposition from native Hawaiians to the construction of another large telescope on Mauna Kea, which they consider a sacred site. Another project, the Giant Magellan Telescope (GMT), is combining seven 8.4-meter mirrors to create an effective aperture of 25 meters.
The TMT project is on hold while it negotiates a way to begin construction in Hawaii. The GMT and another large telescope under construction in Chile, the Rubin Observatory, face rising costs. The pandemic, inflation and supply chain problems are the culprits. TMT and GMT will each cost around $3 billion. Both have philanthropic support, but they also have federal funding. For a time, the National Science Foundation (NSF) supported both projects. But recently, the National Science Council set a $1.6 billion cap on federal support for large telescopes and gave the NSF until May to decide which project to support. A large telescope will be left in the cold.
Meanwhile, the Europeans are calm. O Extremely Large Telescope (ELT) is a third gigantic telescope, currently under construction in Chile. The ELT does not face financial obstacles as it is being built by European Southern Observatory, which is financed by an intergovernmental treaty. At 39 meters in diameter, the ELT is the largest of the three telescopes and will be completed firstin 2028.
The telescope that ate astronomy
Space telescopes cost a thousand times more per kilogram than ground-based telescopes, but they are worth their high price. These telescopes gain the benefit of the total darkness of a space environment, and many forms of radiation that these telescopes can observe, such as gamma rays, ultraviolet light, and infrared radiation, cannot penetrate Earth’s atmosphere to reach ground-based telescopes.
One of these instruments, the Hubble Space Telescope, performed a total cost $16 billion since the U.S. Congress approved its mission in 1977. Another, NASA’s James Webb Telescope, has faced delays and technical challenges, and its budget has ballooned to $5 billion. Its price helped earn it the nickname “the telescope that ate astronomy” – and that was in 2010. At the time of its release in 2021, the price tag doubled to US$10 billion.
NASA has other exciting missions in the works. O Roman Space Telescopewith a 2.4 meter mirror but a field of view a hundred times that of Hubble, it will probably cost more than US$3 billionand the Habitable Worlds Observatorydesigned to “sniff” the atmospheres of Earth-like planets for traces of biology, will arrive around US$11 billion.
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These space telescope missions take a big bite out of a NASA Budget this has been decreasing twenty years ago. As with NSF budget limits, large capital projects leave less money to spend on other forms of research. But the private sector can come to the rescue. SpaceX Starship could be used to launch an entire 6.5 meter mirror, avoiding the complicated and expensive folding mirrors used by the JSWT. The same innovations used with ground-based telescopes could cut the cost of telescopes in space.
As they face the costs of seeing the distant universe and returning rocks from a nearby planet, astronomers and planetary scientists are being brought back to Earth with a jolt. Although it appears to be a golden age for astronomy, the brilliance is diminished by the cost of all that gold and the harsh trade-offs that must be made in a time of fiscal austerity.
