FAQs

The first telescope, used by Galileo to look up at the sky in the 1600’s (The Starry Messenger 1610), forever changed humankind’s understanding of our place in the physical universe. From then on human exceptionalism, built into Western civilization by religious and social norms, suffered a blow that positively changed how we think and make sense of our world. The ELF (and its pathfinder, SELF) telescopes are as bold. These advanced instruments have the potential to reveal humanity’s place among other habitable planets, expand our understanding of biological ecologies beyond Earth, and possibly detect signs of extraterrestrial life. 

SELF and ELF break from current exoplanet studies – detecting life requires high-contrast direct imaging, not the radial velocity or transit studies that have taught us most of what we now know about exoplanets (https://exoplanet.eu/home/). ELF will make cartographic images of nearby planet surfaces. We know what this requires technically for the size and optical properties of the telescope. We can also estimate how many exoplanets we can image in this way as a function of the ELF size. For example, as the instrument diameter ranges from 25 to 50 meters, the number of planet surfaces we can visualize scales from 15 to 100 exoplanets (Berdyugina & Kuhn 2019AJ….158..246B). 

Emphatically no! SELF will be the world’s first fully coronagraphic telescope that can see faint light from close to the central stars it targets. SELF will provide the first view of some large exoplanets like the ones around epsilon Eridani (Llop-Sayson et al. 2021AJ….162..181L; Pathak et al. 2021A&A…652A.121P; Mawet et al. 2019AJ….157…33M; Benedict et al. 2006AJ….132.2206B ; Hatzes et al. 2000ApJ…544L.145H), and it will be capable of detecting “Neptunes” in at least two stellar systems. SELF will provide the first cartographic views of any exoplanet. It will be particularly directed at the Jupiter-like exoplanets and some otherwise unresolvable solar-system planetary rocky objects (like Galilean moons). SELF will be a powerful machine for studying objects with masses between planets and stars, like brown dwarfs and near-planetary-mass companions (Gauza et al. 2015, 2015ApJ…804…96G).  It will see these objects at different stages of their lifecycles, offering an ideal testing-ground to understand how objects that are smaller than normal stars are born and die.

To answer this it’s interesting to note that a growing number of astrobiologists and astronomers believe that life didn’t originate on the Earth. Consider a recent meeting that attracted world attention and that expanded (https://astrobiology.com/2019/04/2019-breakthrough-discuss-conference-migration-of-life-in-the-universe.html) theories that life may have been carried here by comets and asteroids. Some of us believe this may be the most likely explanation for the rapid and universal amino acid basis of all DNA-based life everywhere in the Earth. Similar ideas (called “panspermia”) go back thousands of years to Greek philosopher/scientists, but have been advanced by brilliant nobel-winning modern-era biologists like Francis Crick (who discovered DNA) and astronomers like Fred Hoyle (who discovered how most elements in the universe originated). Since the timescale for life to move between stars is “only” a few million years this means that life on nearby exoplanets could be at about the same evolutionary phase as on Earth. Thus if we want to learn about a cosmic “ecology” we need only look toward the nearby water-bearing exoplanets that ELF is optimized to see. Appreciate that we may be surrounded by life-bearing exoplanets – consider that we are just gaining the technological “reach” to see that the nearest star to the Sun, Proxima Centauri, has a planet spaced from its star so that it could harbor liquid water. Thus, as our technology is on the cusp of allowing us to find exo-life, so might alien life around our neighbor stars be entering this phase. The notion that Earth is part of a slowly changing cosmic ecology is a fascinating idea that we might think of as the stuff of science fiction, but bear in mind, as we live and learn in our own exponentially developing world – science fiction and science facts are more often convergent.

Based on current astrophysical data we can estimate the probability of an exoplanet to have Earth-like properties. Best estimates of this parameter (Bryson et al. 2021AJ….161…36B; Dressing & Charbonneau 2015ApJ…807…45D) imply that a 25m ELF that sees 10 to 15 exoplanets will have about a 90% probability of imaging at least one Earth-like planet, and about a 60% probability of seeing two. We think that even just one surface map of an exoplanet, possibly showing  alien oceans, deserts or life, could change our world view. If we build a 50m ELF we can expect to image  20 Earth-like planets, opening up new scientific domains in exoplanetary geology, atmospheric science, and biology. It becomes possible to test theories of a cosmic ecology (like panspermia) and to plausibly look for the development and evolutionary trends in advanced life. Exoplanet maps that understandably resemble our world may hopefully lead us to doubt human exceptionalism and appreciate life’s interconnectedness. Beyond cartography ELF and its wavelength sensitivity has the even greater potential to teach us more about the form and mechanisms of the global structures we see on alien worlds.

 The short answer is, as big as we can afford, but at least 25 m in diameter or enough to image a handful of exoplanets and one Earthlike with high probability. The LIOM/SELF consortium has spent several years researching the optical technologies we need. Most of this funding has been directed to technology research and development with only a few million Euro’s committed to building the precursor SELF Fizeau telescope at Teide observatory. We need more resources to exploit and demonstrate the practical scalability of all these ideas to a 25-50m diameter telescope through the SELF program. This will also give us confidence that we know more precisely what a larger ELF telescope will cost. For now our estimates for the cost range of a 25-50m ELF are between $100-400M. This is based on scaling knowledge of the new mirror fabrication, photonic and machine learning wavefront methods and opto-mechanical structures. Other funding of $50M will allow the LIOM/ELF consortium to complete and exploit the SELF and to finish a complete ELF design. It also allows us to maintain our momentum toward creating an ELF foundation for the construction of this world-view shattering program. We are moving forward even now to find partners beyond current funding. We received a letter from a Spanish company that commits to a 50M euro ELF contribution when we receive other matching contributions. Our LIOM leadership will be in Asia during early December for discussions with other potential partners to explore forming an ELF foundation with their participation. When SELF is fully operating in approximately 3 years the ELF foundation should finalize the decision for the diameter of ELF between 25-50m.

LIOM does not currently have resources to exploit the SELF pathfinder or to create the ELF final design. The milestones described below will all be achieved with other funding support before 2031. These are key milestones for achieving the ELF goals, although the order in which we reach these is flexible. In some cases we have contingency options. For example, we could use more conventional mirror optics at larger cost, or the ELF foundation might be established with partner institutions before achieving such a large public footprint.

1. Incoherent first light stellar photometric observations with the SELF telescope on Teide (Nov. 2026)
2. Closed-loop phasing of SELF mirrors with a stellar source (Dec. 2026)
3. Dark-hole demonstration in the SELF point-spread function using a bright star (Apr. 2027)
4. Demonstration of a 0.5m thin curvature polished optical mirror with SELF (Mar. 2027)
5. Preliminary design of ELF completed (Jun. 2027)
6. Initiation of the ELF foundation with €150M and three member institutions (Jun. 2027)
7. Demonstration of SELF high-order adaptive optics on at least a V=10 magnitude star (May 2028)
8. First public world event of ELF and social media with over a million followers (Jun. 2028)
9. First scientific publication based on SELF telescope data (Jun. 2028)
10. ELF detailed design completed (Jun. 2029)
11. ELF construction started. (Jan. 2030)
12. ELF first light (Dec. 2035)
13. ELF first exoplanet images (Dec. 2036)