5 ways the James Webb Space Telescope could change science forever
The James Webb Space Telescope is on the verge of starting science operations, ahead of schedule and outperforming its design specifications. While many new discoveries about the Universe are anticipated, ranging from planets to stars to galaxies to dust to black holes and beyond, there are some exciting possibilities for what we don’t expect to find. Thanks to its unique, unprecedented capabilities, JWST might answer five currently open questions about the Universe in very surprising ways. Here are some hints as to what we should keep an open mind about.
Developing superior scientific tools allows us to investigate the Universe in ways never previously possible. NASA’s James Webb Space Telescope, glittering in the sunlight as it recedes from view of the final stage of the Ariane 5 rocket that launched it, goes toward its final destination with possibly the highest amount of fuel we could have asked for. Instead of the expected 5.5-10 years of science operations, we expect JWST to last 20 years or more.
JWST, which is now completely deployed and commissioned, will soon begin science missions. This three-panel animation depicts the difference between 18 unaligned individual photos, those same views after each segment was better arranged, and the final image, which combines the separate images from all 18 of the JWST’s mirrors. The “nightmare snowflake” pattern created by that star can be improved with greater calibration.
Although many cosmic questions will undoubtedly be answered, the most profound transformations will occur unexpectedly. This is a simulated JWST/NIRCam mosaic created with JAGUAR and the NIRCam image simulator Guitarra at the JADES Deep program’s predicted depth. Many records that Hubble set over the course of its 32-year (and-counting) lifespan are likely to be broken by James Webb in its first year of research operations, including records for most distant galaxy and most distant star.
Here are five questions that JWST could potentially answer, forever changing our understanding of the universe. Spitzer (launched in 2003) was older than WISE (launched in 2009), but it had a larger mirror and a narrower range of view. Even the very first JWST image, shown alongside them at comparable wavelengths, can resolve the same features in the same region with extraordinary precision. This is a preview peek at the science we’ll get.
1.) Do biosignatures exist on nearby super-Earths?
If there are additional inhabited planets in our galaxy, near-future technology that will be available within this century, or perhaps even this decade, may be able to discover them first. The JWST, which has a coronagraph as well as incredible spectroscopic infrared capabilities, could find the first evidence of life beyond our Solar System if we’re really lucky. (Credit: NASA Ames/JPL-Caltech/T. Pyle)
JWST could discover unexpected evidence of life in the atmospheres of super-Earth worlds. When an exoplanet passes in front of its parent star, some of the sunlight passes through the exoplanet’s atmosphere, allowing us to break that light down into its constituent wavelengths and characterize the atomic and molecular composition of the atmosphere. We may find distinct biosignatures if the planet is inhabited.
They would be our first-ever hints of life outside the Solar System. Signatures are imprinted when starlight travels through the atmosphere of a transiting exoplanet. Transit spectroscopy can show the presence or absence of numerous atomic and molecular species inside an exoplanet’s atmosphere based on the wavelength and strength of both emission and absorption features.
2.) Are there pristine stars in ultra-distant galaxies?
The very first stars and galaxies that form should be home to Population III stars: stars made out of only the elements that first formed during the hot Big Bang, which is 99.999999% hydrogen and helium exclusively. Such a population has never been seen or proven, but some believe the James Webb Space Telescope will disclose them. Meanwhile, the most distant galaxies are all very brilliant and naturally blue, but not completely pure.
JWST could find extra first-generation starlight by studying and measuring second-generation stars. An illustration of CR7, the first galaxy discovered to contain Population III stars: the earliest stars to originate in the Universe. After all, these stars aren’t pristine, but rather part of a population of metal-poor stars. The very first stars must have been heavier, more massive, and shorter-lived than the stars we see now, and we might separate any additional light to search for evidence of a really pristine stellar population by measuring and understanding the light from the metal-poor stars.
3.) Are black holes energetically active in dusty, early galaxies?
This artist’s impression of the dusty core of the galaxy-quasar hybrid object, GNz7q, depicts a supermassive, expanding black hole at the center of a dust-rich galaxy that’s creating new stars at a rate of about 1600 solar masses per year: a rate almost 3000 times that of the Milky Way.
JWST could reveal hidden supermassive black hole activity by precisely measuring the energy re-radiated by dust. In this comparison view, Hubble data is shown in violet, while ALMA data, which shows dust and cold gas (both of which suggest star-formation potential), is shown in orange. ALMA clearly reveals not only features and details that Hubble cannot see, but also the presence of objects that Hubble cannot see at all. With JWST data, we may be able to determine if the presence of black holes precedes the presence of stars and galaxies.
4.) Was the Universe born with black holes?
This tiny sliver of the GOODS-N deep field, observed with Hubble, Spitzer, Chandra, XMM-Newton, Herschel, the VLT, and other observatories, contains a seemingly inconspicuous red dot. That object, a quasar-galaxy hybrid formed only 730 million years after the Big Bang, could hold the key to unlocking the mystery of galaxy-black hole evolution. Once considered speculative, evidence for the physical existence and ubiquity of black holes is now overwhelming.
JWST will unveil the formation history of galaxies by studying the very first ones. When you start with a seed black hole when the Universe was only 100 million years old, there is a limit to how fast it can grow: the Eddington limit. These black holes either begin larger than our theories predict, form sooner than we recognize, or grow faster than our current understanding allows to acquire the mass values we witness. Investigating quasar-galaxy hybrids could hold the key to solving this mystery.
If black holes existed before the first stars, JWST could provide crucial proof. If the Universe was born with primordial black holes, which is an extremely unlikely scenario, and if those black holes served as the seeds of the supermassive black holes that permeate our Universe, there will be signatures that future observatories, such as the James Webb Space Telescope, will be sensitive to.
5.) How are dark matter-free galaxies made?
Many nearby galaxies, including the whole local group (mainly clustered to the extreme left), show a link between their mass and velocity dispersion, indicating the presence of dark matter. NGC 1052-DF2 is the first known galaxy that appears to be made entirely of ordinary matter, and it was later joined by DF4 in 2019. Galaxies such as Segue 1 and Segue 3 are very dark matter-rich; there is a wide variety of properties, and dark matter-free galaxies are only poorly known.
To separate dark matter from normal matter, both leading formation mechanisms require galaxy interactions. The galaxy NGC 1052-DF4, one of NGC 1052’s two satellite galaxies proven to be devoid of dark matter internally, shows some evidence of being tidally disrupted; an effect that becomes more visible in the panel at right if the surrounding light sources are appropriately modeled and removed. Galaxies like these are unlikely to survive in rich environments without dark matter to hold them together, but the mechanics by which they develop are still being debated.
JWST will teach us whether there is more to the story.
For the first time, in early 2022, a cosmological simulation produced dark matter-deficient galaxies that matched our observed dark matter-deficient galaxies over a wide range of properties. Better observations and larger data sets will be able to test these predictions more robustly in the future, determining the simulation’s effectiveness.