Successful Launch of the Nancy Roman Telescope
Today, August 30, a SpaceX Falcon Heavy rocket successfully launched the Nancy Grace Roman Telescope. This telescope is headed to the Earth-Sun Lagrange point L2, where it will arrive in approximately 90 days. During the journey, the first 40 days will be dedicated to commissioning the instruments and performing status checks, while the support spacecraft will be progressively configured to be fully operational upon arrival. Scientific testing will begin immediately after the first 40 days and will conclude when Roman arrives at L2. The first images from the telescope are expected in early 2027.
The Roman telescope is no ordinary telescope. It will have an unprecedented resolution capacity. Its smallest images will have one billion pixels, and its largest one trillion pixels. Once operational, its Wide Field Infrared (WFI) instrument will record more than a terabyte of data per day (which, incidentally, will not make its analysis easy – starting with the impossibility of transmitting it over the internet).
Before being renamed by administrator Jim Bridenstine in 2020, Roman was called « WFIRST, » an acronym for « Wide Field Infrared Survey Telescope, » which was a very apt description.
It is indeed a telescope that will capture near-infrared wavelengths (just slightly longer than those of the visible spectrum), from 0.48 to 2 µm (0.6 to 28 µm) over a very wide field.
Infrared telescopes, like Roman, unlike visible light or X-ray telescopes, only detect the most energetic sources insofar as they also emit « cool » (or rather, « less hot ») radiation. This launch opens the door to the study and discovery of a multitude of nearby « cold » celestial bodies, such as brown dwarfs and exoplanets, but also to the collection of far more information than other shorter wave telescopes can provide about very distant, « ordinary » objects that are receding from us at high speed (Doppler-Fizeau effect) on account of the expansion of the universe.
Another characteristic of Roman, which distinguishes it from its predecessors, Hubble and JWST, is its very wide field of view. While these two telescopes are designed to observe distant, targeted phenomena in the universe as closely as possible, Roman will study the entirety of our cosmos. Its main instrument, the Wide Field Instrument (WFI), will take extremely wide images of the universe (see the title illustration comparing the fields of view of Hubble and Roman). Its ultra-high-resolution image capture capability will allow for truly unparalleled comparisons.
This will allow us to better study dark energy and dark matter, which remain so poorly understood. The goal is still not to « see » them, but to observe their effects with as much precision as possible and on different objects, in order to better understand them. To demonstrate their reality and perceive their nature, proponents of these theories hope to use « messengers » that will highlight the « anomalies » they are looking for.
The wide field of view of Roman would be all the more useful for this purpose since the aim is not to see a celestial body precisely, but rather environments through these celestial bodies in order to compare them. To study the effects of dark energy via the expansion rate, the designers of Roman want to measure the luminosity distance of type Ia supernovae (thermonuclear explosions ≠ supernovae that implode due to core collapse), whose absolute luminosity is known, and to study weak gravitational lensing over the greatest possible depth of space. Depending on the distance, the effects of dark energy must have varied over time for similar masses, given the accelerating expansion over time.
The variations in the expansion rate of the universe over long periods will be another focus of Roman’s research. He may not confirm this acceleration, but that is not the most likely outcome. Furthermore, confirmation of the accelerated expansion, but with inconclusive results regarding the effects of dark energy or dark matter on baryonic matter, would lend considerable weight to the theory of vacuum properties developed by André Maeder, published in January 2017 in *The Astrophysical Journal*.
Note: André Maeder, astrophysicist and professor emeritus at the University of Geneva (UNIGE), does not deny the reality of acceleration—quite the contrary—but considers it to be « simply » a consequence of the large-scale vacuum (within which the rules of general relativity apply), based on the hypothesis of « scale invariance of the vacuum, » the hypothesis that empty space has the same properties regardless of the scale at which it is considered. In his calculations, this invariance reveals a very small acceleration term for the expansion that opposes the gravitational force…exactly what we are looking for! Therefore, any dark energy or dark matter would become unnecessary to explain acceleration.
To detect these faint radiations, Roman (like the JWST) will benefit from its L2 location, meaning it’s shielded from sunlight by the Earth. But to study exoplanets, and this is a major first, it will be equipped with a coronagraph that will allow it to block out the light from the star on which the targeted planet depends.
Let’s wish this new telescope good luck. Without further ado, we can already say that the story has gotten off to a good start. The launch wasn’t scheduled until 2027, but it was brought forward. Thank you, SpaceX!
