new survey of the sky will reveal the universe in unprecedented detail

When you look up at the night sky, it appears unchanging. But if you look deep enough you will find that the sky is in fact constantly shifting. Satellites, asteroids and interstellar objects pass by. Stars not only shine brightly, they can suddenly burst with energy or explode in bright supernovae.

There is a plethora of explosive and cataclysmic phenomena waiting to be witnessed. For physicists, this is an opportunity to study our universe and physics that we can’t reproduce on Earth.

A whole new era of discovery is opening with the NSF-DOE Vera C. Rubin Observatory. For the next ten years, Rubin will create a high-definition video of the southern sky, revealing our universe in an unprecedented way. Many of the objects it finds will have never before been seen by human eyes.

More than 20 years in the making

This moment has been more than 20 years in the making, from the concept to completion of the Rubin Observatory.

Located on a dark sky mountaintop in Chile, the observatory represents a generational leap in astronomy with its ultra-wide, deep and high-resolution imaging capabilities.

Rubin has the largest camera ever built, with 3,200 megapixels. Each image scans an area equivalent to 40 full moons. The resolution of the images is so high that if we pointed the camera toward a lime located 24 kilometres away, it would be able to resolve exactly what type of fruit it is.

Last year, Rubin amazed us with its first test images. These images revealed a swarm of new asteroids never before detected, stars varying in our Milky Way and beautiful deep images of galaxies. This is just a taster on what is to come; this week Rubin started publicly sharing hundreds of thousands changing sky objects per night.

The telescope will be uniquely used for the Legacy Survey of Space and Time. This ten-year-long survey aims to solve the biggest mysteries of the universe – and the nature of the physics out there.

20 billion galaxies

With its advanced imaging capabilities and its systematic scan of the sky, Rubin will image an incredible number of objects in our universe over the next decade.

Starting in our cosmic backyard, our Solar System, it will make 6 million detections of asteroids. Moving toward our galaxy, it will catalogue 17 billion stars. Farther away, it will gather colour images of 20 billion galaxies.

The same patch of the sky will be imaged up to 100 times each year. With an expected 10 terrabytes of image data per night, the amount of data Rubin will deliver in a single year will be greater than all optical observatories combined.

With this data, we aim to answer fundamental questions. These include the nature of the most mysterious components of our universe: dark matter and dark energy.

I am particularly interested in using the data to measure whether the universe expansion maintains a constant acceleration or changes with cosmic time. This accelerated cosmic expansion is attributed to dark energy, which comprises 70% of our universe. Yet we still don’t know what it is.

By itself, this measurement would be amazing, especially since recent observations have hinted the expansion rate may be changing. From the physics point of view, this will allow us to narrow down which potential theories can explain dark energy.

A firehose of cosmic treasures

To find changing sky objects, we compare a new image to an “old” or reference image. The difference between the two images can reveal a new object or a change of brightness.

So how do we find the most interesting exploding stars or asteroids within this mass of detections?

Rubin has selected seven “community brokers”. A broker is both the infrastructure and the team that receives this data firehose within minutes of detection, processes it to find the most exciting objects, and makes them publicly available.

One of these community brokers is Fink, which I have the privilege of co-leading.

Fink is made up of hundreds of scientists and engineers around the world working together to understand our universe. With the incredible Rubin data, comes a great opportunity but also a big challenge.

We need state-of-the-art technologies such as distributed computing (a network of computers, similar to commercial cloud services) and artificial intelligence tools to process the data very fast. We are talking about analysing thousands of detections from Rubin every minute or two, and up to 10 million every night for ten years.

Become a Rubin citizen scientist

You can also engage with Rubin right now.

Rubin’s first images are available online and you can use apps such as Orbitviewer to track asteroids, as well as look at deep images with SkyViewer.

You can also become a Rubin citizen scientist. For example, you can help to identify changing objects in our universe with Rubin Difference Detectives and find comets with Rubin Comet Catchers.

The data from community brokers is also publicly available. Through our Fink portal, you will be able to inspect the latest detections from Rubin just minutes after an image has been taken.

The data may not look like the stunning Rubin first light images. But they come directly from the telescope and are full of universe treasures.

Correction: this article originally stated the Legacy Survey of Space and Time has started. It has been amended to make clear the survey has not yet started but that the Rubin Observatory has started publicly sharing data.