APR 28, 2022 10:00 AM PDT

Weighing an Invisible Object in Space

WRITTEN BY: Amanpreet Kaur

Our Universe is full of exotic objects and phenomena, and we have built telescopes and satellites to try and attain a deep understanding of it all. Sometimes, objects in space come to our aid and they act like magnifying lenses to provide us a glance at other faint (very far away) sources. In astronomy, this phenomenon is called Gravitational Lensing, which states that when one massive object (“foreground source”) passes in front of another (“background source”) across our line of sight, it bends the light coming from this background source and we end up seeing multiple magnified images of this far-away source. This bending of light occurs due to the gravitational field associated with the foreground source, which distorts the light coming from the background object. The foreground source is the “lensing object” and it can be a star, a galaxy, a cluster of galaxies, or black holes, etc. The more massive the lens is, the stronger is the lensing effect because of its strong gravitational field.  

Astronomers found that this lensing object can also be an exoplanet, which is less massive as compared to other objects in space but can create the lens effect on a faraway background star. In this case, this phenomenon is called microlensing. Astronomers have been able to find more than 50 exoplanets using this method. Moreover, we can also estimate the mass of these lenses provided we know two parameters: (1) the size of the theoretical Einstein ring  (for perfect alignment, the background star would look like a ring image around the lensing object.) and (2) parallax ( an angle formed at the object when viewed from two different angles). Using these two parameters, one can find the mass of this lens. The first parameter is not that hard to obtain, but the second one is not always available. 

For the first time, astronomers from France, Poland, Belgium, and the USA collaborated to witness the lensing effect in real time where they witness the background star’s image in motion as well as rotation, all thanks to the lensing effect by an unknown (dark) foreground object. They used the Very Large Telescope Interferometer (VLTI) along with many other telescopes from the ground as well as the Spitzer Space Telescope in the sky to obtain real-time observations of this effect on a star called Gaia19bld. This collaboration of various telescopes as well as precise measurements from VLTI allowed this team to calculate the mass of the dark lens to be =1.147 Msun. The nature of this object however is still uncertain. These results were published in the highly regarded peer-reviewed journal, Nature, in December 2021. 

Source: Nature ArticleWarsaw Press Release

About the Author
PhD in Physics
Aman (she/her) is a scientific writer at labroots and an astrophysics researcher at Penn State University. She works in the field of high-energy astrophysics such as black holes, gamma-rays, etc., and collects data from various space telescopes to conduct her research. She received her doctorate from Clemson University in Physics. On a personal note, she loves spending time out in nature; camping or hiking. If given a choice, she will decorate her house only with plants, did she say she likes plants? :D
You May Also Like
JUN 21, 2022
Chemistry & Physics
A new feedback system could improve fusion reaction efficiency
JUN 21, 2022
A new feedback system could improve fusion reaction efficiency
We’ve all heard about nuclear fusion at least once in our lives, and probably because we’ve been 10 years aw ...
JUL 01, 2022
Technology
Robotic Fish for Cleaning up Microplastics
JUL 01, 2022
Robotic Fish for Cleaning up Microplastics
Microplastics are tiny pieces of plastic, usually about 5mm or less in size. They often develop over time as plastic bre ...
JUL 22, 2022
Space & Astronomy
BepiColombo Snaps Photos of Mercury
JUL 22, 2022
BepiColombo Snaps Photos of Mercury
On June, 23, 2022, the BepiColombo mission made its second gravity assist of the planet Mercury. BepiColombo is a collab ...
JUL 16, 2022
Chemistry & Physics
The Probe that was Almost Swallowed by an Asteroid
JUL 16, 2022
The Probe that was Almost Swallowed by an Asteroid
To study the formation of our planet, as well as the overall solar system, and to study the possible source of all the o ...
JUL 28, 2022
Space & Astronomy
Gemini's GHOST Achieves First Light!
JUL 28, 2022
Gemini's GHOST Achieves First Light!
GHOST – the Gemini High-resolution Optical SpecTrograph – recently achieved its first light. This new telesc ...
AUG 03, 2022
Space & Astronomy
Moon lava pits might be toasty environments for future astronauts
AUG 03, 2022
Moon lava pits might be toasty environments for future astronauts
In a recent study published in Geophysical Research Letters, a collaborative research team from the University of Califo ...
Loading Comments...