Knowledge Nugget | CosmoCube : How a tiny satellite could reveal the early universe

3. CosmoCube would spend around 40 minutes on the far side during every two-hour orbit. 

4. Over a proposed two-year mission, the satellite could collect roughly 1,000 hours of data at extremely low radio frequencies.

5. The measurements could offer scientists a clearer picture of the cosmic dark age and the transition towards the formation of the first stars and galaxies.

Why is the early universe difficult to observe? 

6. After the Big Bang, the universe entered a period known as the cosmic dark age. It lasted roughly 150 million years before the first stars began to form.

7. Although there were no stars yet, the universe was filled with hydrogen. These atoms produced a faint radio signal known as the 21-centimetre line, which carries information about conditions in the early universe.

8. Detecting this signal from Earth, however, is extremely difficult. Earth’s ionosphere blocks the relevant low-frequency radio waves, while human-made signals from FM radio, telecommunications systems, and satellites can further overwhelm the extremely faint cosmic signal.

9. The result is a major observational gap in our understanding of the universe’s early history. The international team behind CosmoCube proposes placing the small spacecraft in orbit around the Moon, allowing it to collect measurements as it passes behind the Moon’s far side. 

10. The Moon would block radio noise originating from Earth, creating a much quieter environment for the spacecraft’s instruments.

What is the Big Bang theory? 

1. The genesis of the Big Bang theory can be traced to eminent scientist Edwin Hubble who not only discovered that there are galaxies other than the Milky Way but also that we live in an ever-expanding universe in which all galaxies are moving away – the farther the galaxy, the faster it is receding! 

2. These profound implications about the universe were also proposed by Georges Lemaître, a Belgian cosmologist and Catholic priest, who is considered as the father of the Big Bang theory.

3. The prevalent belief is that the universe came into being nearly 13.8 billion years ago with a massive explosion in an extremely small ‘subatomic ball’ with unimaginably small volume and infinite temperature and density, known as the singularity. 

4. This is widely known as the “Big Bang” — the most acknowledged theory of our existence and the evolution of our universe. All matter that exists today in the universe sprung forth from that single point in an epic explosion.

5. According to the late British physicist Stephen Hawking, the laws of physics and time cease to function inside that tiny particle of heat and energy. 

6. The ordinary real time as we know now shrinks infinitely as the universe becomes ever smaller but never reaches a definable starting point. There was absolutely nothing before the Big Bang, he said. 

7. Although during an explosion debris fly out and spread unevenly at different distances from the blast centre, Big Bang shot out the same amount of material, over the same distance in all directions giving birth to a homogenous universe in space and time.

8. Thus what happened was neither big nor with a bang. What triggered this, we may never know as singularity and laws of physics as we know them don’t mix.

9. What we do know is that after the Big Bang, space started to expand and cool down at a speed faster than light. The period when this happened is identified as the cosmic inflation period.

10. As the universe continued to expand and became cooler, energy started getting converted to matter, antimatter, particles and radiation.

11. About 380,000 years after the Big Bang, the universe entered the ‘Cosmic Dark Ages’ since the atoms that formed were opaque to light.

12. Prevailing theories and many observations later, when the first stars were formed, they heated up the gas in the universe again, ending the Dark Ages. This gradually led to the galaxies, stars and planets that we know today, including life on Earth itself.

13. Usually, scientists can “look back in time” in the universe by looking at really distant objects in the universe. If we observe something that is a hundred million light-years away, we are technically looking at an object as it was a hundred million years ago.

14. But since there were no stars or planets in the ‘Cosmic Dark Ages’, it is a point in time that scientists have never been able to observe before.

(Infographic source: AI generated)

What could CosmoCube reveal?

1. It could help address concerns dark matter and its role in the early universe.

2. Scientists believe dark matter’s gravitational influence helped pull hydrogen and other matter together, eventually contributing to the formation of the first stars and galaxies. 

3. Studying the 21-centimetre signal could therefore provide clues about how these structures emerged from the early universe.

4. Eloy de Lera Acedo, an astronomer at the University of Cambridge and co-author of the study, said the far side of the Moon offers a unique combination of protection from Earth’s radio interference and a broad view of space.

How would a small spacecraft work to achieve a difficult task? 

5. Despite its relatively small size, CosmoCube would require sophisticated systems to distinguish the faint cosmic signal from noise produced by the spacecraft itself and other sources.

6. The satellite would use a lightweight radio antenna to detect the early-universe signal. It would also repeatedly determine its own position using onboard information and observations of its surroundings.

7. These checks would help researchers identify interference originating from the spacecraft and prevent it from being mistaken for a genuine cosmic signal.

8. After the mission, mathematical models would be used to remove additional foreground interference, including radio emissions from the Milky Way and other sources.

9. Will Grainger, an astronomer and study co-author, said the mission would require “clever design techniques” to carry out ambitious science from a small spacecraft operating in a challenging environment.

10. The researchers are working with partners to develop and test CosmoCube models, including assessments of the spacecraft’s thermal performance in space.

11. With sufficient support, the team believes the satellite could be ready for launch within about five years. However, the proposed mission faces a potential challenge: the lunar far side may become increasingly busy.

12. The United States and India are among the countries planning missions to the Moon’s far side. As more spacecraft and infrastructure reach the region, the naturally quiet radio environment that makes it attractive to astronomers could become increasingly difficult to preserve.

13. If CosmoCube gets the opportunity to operate as planned, its relatively small spacecraft could provide scientists with a rare window into a period of cosmic history that has so far remained largely hidden.

BEYOND THE NUGGET: What is Dark Matter? 

1. Everything  that we can see — stars, planets, gas, dust — makes up only about 5% of the universe. Another 27% is this elusive dark matter, which neither emits nor absorbs light, making it undetectable by traditional telescopes. Yet without it, galaxies would not hold together, and the cosmic web that binds the universe would fall apart.

2. One of the most compelling clues to dark matter comes from the way galaxies move. Stars at the outer edges of spiral galaxies rotate much faster than expected — far too fast for the visible matter alone to account for.

3. Without something unseen providing extra gravity, these galaxies should spin apart like leaves in a storm. Galaxy clusters, too, behave as if they are embedded in vast halos of invisible mass.

4. Dark matter, then, acts like the hidden scaffolding of the cosmos — an unseen framework on which galaxies, clusters, and cosmic filaments are built. This gravitational scaffold shaped the formation of structure in the early universe and continues to hold it all together today. 

5. Solving the dark matter puzzle could change how we understand matter, forces, and the origin of structure in the cosmos. It may open doors to new physics beyond the Standard Model — our current best theory of particles and forces.

Post Read Question

Which of the following is/are cited by the scientists as evidence/evidences for the continued expansion of universe? (UPSC CSE, 2012) 

1.  Detection of microwaves in space

2. Observation of redshift phenomenon in space

3. Movement of asteroids in space

4. Occurrence of supernova explosions in space

Select the correct answer using the codes given below:

(a) 1 and 2

(b) 2 only

(c) 1, 3 and 4

(d) None of the above can be cited as evidence

Answer: (a)

(Sources: Suitcase-sized spacecraft may reveal what happened before first stars formed, Nothing existed before Big Bang: Stephen Hawking, The Big Bang’s ‘missing’ half: Why new research suggests black holes swallowed the universe’s antimatter, Galaxies flying away: How Hubble’s redshift led us to the Big Bang, A science teacher explains: The Big Bang Theory)

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