[Music throughout]
Almost all observations of the universe
come by collecting light in various wavelengths.
This light can show variations in brightness,
reveal structure in cosmic objects, and contain huge amounts of information
in how its wavelengths are distributed across a spectrum.
Researchers have captured these details for decades, even centuries.
But often they are limited to just a brief snapshot of an object in space.
A single still image.
In recent years,
scientists have been making more observations with a fourth component: time.
Space isn't static, and recording data through a given duration called
Time-Domain Astronomy tracks how details of an object like brightness,
spectrum, location and structure change. An object can vary,
it can move, or it can do both.
There are three main classes of how an object can vary in time.
Periodic, quasiperiodic, and transient. Periodic change
means there is a regular fixed pattern to the change.
Sunrise and sunset or a blinking pulsar are examples.
Quasiperiodic means that there is a pattern and the change
or event happens again and again, but not as regularly,
like hurricanes or flashes from hot material around black holes.
Transient events are less predictable and often happen only once.
Earthquakes and supernovas are transients.
These are the hardest to observe because they can be brief and start unexpectedly.
If telescopes aren't looking in the right place, they miss the beginning or
even the entire event.
NASA's upcoming
Nancy Grace Roman Space Telescope will be specially equipped
to be a groundbreaking tool for Time-Domain Astronomy.
It will observe from space so it won't have daily time restrictions
like ground based telescopes, which can only observe at night.
It will have image quality like Hubble, but with a field of view
at least 100 times larger.
So it will be able to observe large portions of the sky all at once.
Roman is a survey mission, which means that in addition to a large,
singular field of view,
Roman can repoint that view more efficiently during observation
periods, tiling even larger areas of sky 1000 times faster than Hubble.
For one of these, called the Galactic Bulge Survey,
Roman will aim its expansive view at the center of our galaxy
and observe a two-square-degree region in infrared wavelengths
that cut through the obscuring dust to reveal millions of stars.
During this survey, Roman will take a new image
every 2 minutes for more than 62 days and then repeat this six times over
five years for a total of 400 days of coverage.
Roman will be watching for planets transiting, or eclipsing, their host stars
and rare gravitational lensing events where the gravity of foreground objects
lenses the light of background stars causing changes in brightness.
These peaks can reveal new planetary systems, rogue planets
untethered to a star, and even black holes that would otherwise be invisible.
A single snapshot of the sky can't show these events;
they require constant or very regular monitoring to reveal.
Roman’s main objective in this survey is simply finding new planets and black holes.
Astronomers anticipate that Roman could discover over 1,000
microlensing and 100,000 transiting planets from this survey alone.
Observatories like the James Webb Space Telescope
can then follow up with a narrower, more targeted view
and learn key details about the most interesting discoveries.
Roman will also perform time-oriented surveys aimed at furthering our
understanding of the universe's history and future. With its wide and steady gaze,
the Nancy Grace Roman Space Telescope will be a key player in the future of Time-Domain Astronomy.
[NASA]