Astronomy Rewind: September 2020
Unraveling dark energy, OSIRIS-REx mission update, NASA at home, and more
“There are billions of places out there that we know nothing about. The fact that we know nothing about them excites me, and I want to go out and find about them. And that’s what Science is”
— Brian Cox
As we step on to the pre-penultimate month of 2020, it’s worth spending time in introspecting on the various developments in space exploration that happened in September — a month dedicated to the Roman God of Fire.
September had us asking some very interesting questions like if there was life on Venus, or if a planet (and life on it) can survive the death of its host star. We also had some interesting answers like why the surface or our airless moon has rust? On the technology front, we saw some exciting developments with scientists inventing a device to detect extra-terrestrial life.
With all of this and so much more happenings around us, we have handpicked some of the top stories you may have missed to rewind and introspect on.
Discovering a black hole that shouldn’t exist
Our Sun has a mass of about 1.989*10³⁰ kg. If you apply Einstein’s E=MC², we would get the equivalent energy of one solar mass, i.e 1.7*10⁴⁷ J. This is an unimaginably huge number. Now, multiply that by 8 and you get the energy released in a recent black hole collision that astronomers have observed. Black hole mergers are interesting. For one part, they give us such insane numbers and physics at play, and for the other, they produce the gravitational waves.
This observation (labeled GW190521) breaks a bunch of records. It is by far the most massive and distant source for gravitational waves we know. Scientists estimate that the collision resulted in a merger creating a new 142 solar mass black hole.
One of the colliding black holes was at about 85 solar masses. There is something strange about this number. In the world of black holes, scientists term the mass between 65 and 120 solar masses as the “pair-instability mass gap”. The bottom line is, from what we know about how black holes form, none of them should exist in this mass range. Yet, here were are, observing one such black hole!
This discovery gave us a lot more questions than answers.
Here’s a research paper that tries to explain how a black hole can exist in such a mass gap-
Binary black holes in the pair-instability mass gap
Pair instability (PI) and pulsational PI prevent the formation of black holes (BHs) with mass
For more information on this news, visit-
A "bang" in LIGO and Virgo detectors signals most massive gravitational-wave source yet
LIGO and Virgo researchers have detected a signal from what may be the most massive black hole merger yet observed in…
High-resolution image of the surface of the Sun captured by the GREGOR Telescope
Have you ever wondered what it takes to spot a needle on a soccer field perfectly sharp from a distance of one kilometer? Believe us that a simple correction for astigmatism can prove to be a good fortune as this small upgrade has corroborated Europe’s largest solar telescope GREGOR to capture an unprecedented pop-corn-like surface of the Sun. Does this solution ring a bell? You must be thinking of the Hubble space telescope which received a similar upgrade back in 1993.
Spectacular images which resolved details as small as 50 km on the Sun proved to be a significant breakthrough in the study of the Sun’s magnetic fields. These fields aren’t visible on their own, and so must be studied through its interaction material. There are still many puzzling queries that have been left unanswered.
The redesign required sophisticated engineering, from computer simulations of optical paths to ensure accurate focus, to polishing mirrors to within an accuracy of 6 nm.
“The project was rather risky because such telescope upgrades usually take years, but the great teamwork and meticulous planning have led to this success. Now we have a powerful instrument to solve puzzles on the Sun”, remarked Prof. Dr Svetlana Berdyugina.
The progress we made here truly reflects on a new age of solar observations. Scientists also believe that GREGOR can prove efficacious in warning about possible threats by catastrophic and callous activities that are occurring on the stellar surface this very moment, as you read this article.
Did we find the source of dark energy?
Have you ever wondered if our universe is constant or expanding? Either of these options leaves us with some mind-bending puzzles. It is known for a while that the Universe is indeed expanding, but why? What makes it even more tricky is the fact that this expansion is accelerating. Scientists simply didn’t know the answer to why this happens, and as a result, the mysterious dark energy was hypothesized.
Right now, we have a deeper idea of what it is not than what it is. We know that it exists because we observe its effects very clearly. It is actually the other way round. Whatever we observe, we attribute it to the dark energy. It seems to be some kind of energy intrinsic to empty space, more substantial than anything else we know and it somehow keeps getting stronger as time passes by.
So, did we find any secret about it recently? Kind of.
Researchers from the University of Hawaii at Mānoa made a novel prediction that the dark energy responsible for this accelerating growth comes from a vast sea of compact objects spread throughout the voids between galaxies. This conclusion is part of a new study published in The Astrophysical Journal.
The Generic object of dark energy (also known as GEODE and GEODEs) refers to a class of non-singular theoretical objects that mimic black holes, but with dark energy interiors instead. Because GEODEs mimic black holes, it was assumed they moved through space the same way as black holes.
“This becomes a problem if you want to explain the accelerating expansion of the universe,” said UH Mānoa Department of Physics and Astronomy research fellow Kevin Croker, lead author of the study.
The researchers estimated that the spinning layer around each GEODE determines how they move relative to each other. If their outer layers spin slowly, GEODEs clump more rapidly than black holes. This is because GEODEs gain mass from the growth of the universe itself. For GEODEs with layers that spin near the speed of light, however, the gain in mass becomes dominated by a different effect, and the GEODEs begin to repel each other.
“The dependence on the spin was quite unexpected,” said Farrah, a faculty member at the UH Institute for Astronomy.
“If confirmed by observation, it would be an entirely new class of phenomenon.”
This research provides us with a clear vision to think about the physics behind the expansion of the universe.
For more information, you can visit-
Mission Update- OSIRIS-REx Begins its Countdown to TAG
Just 60 grams of a rock, drifting 334 million kilometers away from earth, is enough to elucidate the story of the solar system.
Get ready to witness a historic moment in space exploration — the touchdown and collection of a sample of an asteroid. On October 20, OSIRIS-REx will descend to asteroid Bennu’s rocky, boulder-filled surface, touch down for a few seconds and collect a sample of the asteroid’s rocks and dust, which will be returned to earth. This will be the first Touch-And-Go (TAG) sample collection of the mission, launched in 2016.
To Bennu and back
Bennu is a near-earth asteroid, with an estimated 1-in-1800 chance of hitting earth in 2170. OSIRIS-Rex, orbiting Bennu, will perform a series of maneuvers, for about 4.5 hours, to touch down at site Nightingale, a rocky area 16 m in diameter in its northern hemisphere. The site has a fair amount of fine material but is surrounded by building-sized boulders.
With six specialized instruments onboard, the entire asteroid was mapped for the mission. As it is 334 million km from earth, it will take about 18.5 minutes for signals to travel to it. This time lag prevents the live commanding, so the spacecraft performs the entire sequence autonomously.
After traveling four hours on a downward trajectory, the spacecraft performs a “Checkpoint” maneuver at an altitude of 125 m. This adjusts the position and speed of the spacecraft. About 11 minutes later, it performs the “Matchpoint” burn at an altitude of 54 m, matching the asteroid’s rotation. The spacecraft then descends to the surface, touches down for less than 16 seconds, and fires pressurized nitrogen. The gas agitates and lifts surface material, which is then caught in the arm’s collector. After this, OSIRIS-REx fires its thrusters to back away from the surface and navigates to a safe distance.
On October 22, OSIRIS-REx’s camera checks whether the arm contains Bennu’s surface material. The spacecraft will perform a spin maneuver to determine the mass of the sample. If collection is successful, it will be placed in the Sample Return Capsule (SRC) for a return to the earth; else, the spacecraft readies up for two more attempts.
“The information we’re going to gain from OSIRIS-REx, it’s going to help pull back the curtains on the origin of this planet, on the origin of life itself,” says NASA Chief Scientist Ellen Stofan.
Indeed it will be a treasure trove of information for the scientists to come, for the next few decades, about the origin of the solar system and the story of life.
Quarantine Special- NASA at Home
NASA has made it possible for you to explore the vastness of the universe through its NASA at home initiative. There are a lot of resources they provide to you and here are our top picks you should definitely check out-
Student Project: Code a Mars Helicopter Video Game | NASA/JPL Edu
Create a video game that lets players explore the Red Planet with a helicopter like the one going to Mars with NASA's…
NASA's Curious Universe
Our universe is a wild and wonderful place. Join NASA astronauts, scientists and engineers on a new podcast adventure…
Visit the home page of this initiative for more information-
Stay tuned for the next edition of rewind where we will unwind even more intriguing news stories from across the globe. Until then, happy exploring the cosmos from the comfort of your home!
“I’m sure the universe is full of intelligent life. It’s just been too intelligent to come here.”
― Arthur C. Clarke