Nasa finds that there are far fewer galaxies than first thought, with numbers in the billions rather than trillions
- Previous estimates indicate that there were about two billion galaxies
- But new data from Nasa’s New Horizons spacecraft suggests this is not the case
- Instead, Nasa now estimates that there are hundreds of billions of galaxies
Nasa has revealed that there are far fewer galaxies in the universe than previously thought.
New measurements taken by Nasa’s spacecraft New Horizon amount to hundreds of billions, rather than the two trillion.
The findings suggest that the universe may be much smaller than previous estimates have suggested.
The Milky Way is perhaps just one of the billions of galaxies in the universe, rather than trillions as previously estimated
In the study, Nasa took new measurements of the weak background glow of invisible galaxies.
Mark Postman of the Space Telescope Science Institute in Baltimore, and a lead author of the study, said: ‘This is an important number to know – how many galaxies are there? We simply do not see the light from two trillion galaxies. ‘
Previous estimates are based on observations of deep air by Nasa’s Hubble Space Telescope.
However, Hubble relied on mathematical models to estimate the number of galaxies, as many galaxies were thought to be beyond the space telescope’s ability to detect in visible light.
Unfortunately, Hubble still suffers from light pollution due to its position in the inner solar system.
To overcome this problem, Nasa turned to its New Horizons spacecraft, which experiences an ambient sky ten times darker than the darkest sky Hubble has seen.
Tod Lauer of NSF’s NOIRLab, a lead author of the study, said: ‘These types of measurements are extremely difficult. Many people have been trying to do this for a long time.
“New Horizons gave us a vantage point to better measure the cosmic optical background than anyone could have done.”
Nasa is turning to its New Horizons spacecraft, which is 10 clouds darker than the darkest sky Hubble has seen.
To estimate how many galaxies there really are, the team analyzed existing images from New Horizons.
To bother the faint background glow in some images, Nasa was forced to remove light from the Milky Way stars reflected in the camera.
Fortunately, the remaining signal was about measurable, which allowed a more accurate estimate of the number of galaxies.
Nasa is now planning a follow-up study with its upcoming James Webb Space Telescope.
Nasa said: ‘NASA’s upcoming James Webb Space Telescope may be able to help solve the mystery. If faint, individual galaxies are the cause, then Webb ultra-deep field observations can detect it. ‘
This study is accepted for publication in the Astrophysical Journal.
WHAT IS A MONSTER GALAXY?
Monster galaxies, also known as galaxies, are considered the ancestors of massive galaxies such as the Milky Way in the modern universe.
The ancient objects appeared shortly after the big bang and are characterized by rapid star formation and mass growth, which gave birth to new stars thousands of times above that of our own galaxy.
This results in small but incredibly dense galaxies that burn quickly through all their cosmic gas – the ‘fuel’ used to create new stars.
Once they consume this gas, some within about 100 million years after birth, they become tranquil or ‘red and dead’ galaxies – common in our universe today.
Scientists hope that studying the mysterious objects will provide answers to key questions about the formation and evolution of modern galaxies, such as the Milky Way.
Monster galaxies, also known as galaxies, are considered the ancestors of massive galaxies such as the Milky Way in the modern universe. This image is an artist’s impression of ZF-COSMOS-20115, a monster system discovered in 2017