6Pre-AdvancedExamScience

Scientists Complete the Largest 3D Map of the Universe

The Dark Energy Spectroscopic Instrument has finished the largest and most detailed 3D map of the universe ever created. By mapping over 47 million galaxies, this groundbreaking achievement will help scientists investigate dark energy, the mysterious force driving the expansion of the cosmos.

2 min readLevel 6April 20, 2026

By Flalingo Editorial Team

Vocabulary

Study these words before reading the article. Click the audio button to hear pronunciation.

milestone

/ˈmaɪlstəʊn/

noun

An important event or achievement that marks a significant stage in a process or project.

“Completing the human genome project was a major milestone in the history of biological science.”

unprecedented

/ʌnˈpresɪdentɪd/

adjective

Never having happened or existed before; completely new and original.

“The country faced an unprecedented economic crisis that no previous policy could have predicted.”

surpassed

/səˈpɑːst/

verb

Went beyond what was expected or achieved previously; exceeded.

“The new solar panel technology surpassed all performance targets set by the engineering team.”

accelerating

/əkˈseləreɪtɪŋ/

adjective

Increasing in speed or rate over time.

“The accelerating pace of climate change has prompted governments to adopt stricter environmental policies.”

endeavor

/ɪnˈdevə/

noun

A serious and determined effort to achieve something, especially something difficult or important.

“The construction of the international space station was a remarkable scientific endeavor.”

evolving

/ɪˈvɒlvɪŋ/

adjective

Gradually changing or developing over a period of time.

“Our evolving understanding of genetics has led to significant advances in medical treatment.”

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Article

Click on any underlined word to see its definition. Highlighted words are from the vocabulary section.

An international team of scientists has achieved a remarkable milestone in modern cosmology. The Dark Energy Spectroscopic Instrument, known as DESI, has completed the largest 3D map of the universe. This extraordinary project had been planned as a five-year survey of the night sky. DESI, which is mounted on a telescope in Arizona, finished its observations ahead of schedule. The instrument used 5,000 fiber-optic sensors to capture light from distant cosmic objects.

The results have far surpassed the original expectations of the research collaboration. Scientists had initially planned to gather data on 34 million galaxies and quasars. However, DESI performed so efficiently that it recorded more than 47 million galaxies and quasars. It also observed over 20 million nearby stars that are being used to study the Milky Way. DESI has now measured six times as many cosmic objects as all previous surveys combined.

The primary purpose of this unprecedented map is to investigate dark energy. Dark energy is the fundamental force that makes up approximately 70 percent of the universe. It is believed to be driving the accelerating expansion of the cosmos. Surprising early results had hinted that dark energy might be evolving over time. If this were confirmed, it would represent a major shift in our understanding of physics.

Although the planned survey is now complete, the DESI project will continue its exploration. The instrument will keep observing the sky until 2028 to further expand the map. More than 900 researchers from over 70 institutions worldwide are involved in this endeavor. The first results from the full five-year dataset are expected in 2027. Scientists remain eager to discover what new surprises may be hidden within the data.

Comprehension Quiz

Test your understanding of the article with these multiple-choice questions.

1
How many galaxies and quasars did DESI ultimately observe during its five-year survey?
2
What is the primary scientific purpose of the DESI 3D map?
3
What surprising finding did early DESI data suggest about dark energy?
4
When are the first results from the complete five-year DESI dataset expected?
5
Approximately what percentage of the universe does dark energy make up?

Discussion

Answer these comprehension questions about the article.

1
According to the article, what was the original goal of the DESI project, and how did the actual results compare to expectations?
2
The author suggests that dark energy may not be constant. What evidence from the article supports this claim?
3
What does the passage indicate about the role of international collaboration in large-scale scientific research?
4
According to the article, why is understanding dark energy considered so important for the field of cosmology?
5
What can be inferred from the fact that DESI completed its survey ahead of schedule and with more data than planned?

Further Discussion

Share your opinions on these open-ended questions.

1
Do you think governments should invest large amounts of money in space research when there are urgent problems on Earth? Why or why not?
2
If you could ask one question about the universe and receive a definitive answer, what would it be and why?
3
How do you think discoveries about the universe affect ordinary people's daily lives, if at all?
4
In your opinion, what are the greatest benefits of international scientific collaboration compared to individual national projects?
5
Some scientific discoveries challenge long-held beliefs. Can you think of an example from history where a new discovery changed the way people understood the world?