NASA’s new telescope will tell about the birth of the Universe and will search for extraterrestrial organic matter

(ORDO NEWS) — The US space agency has completed the development of the SPHEREx orbital observatory. Specialists are moving from computer simulation to the creation of a tool “in hardware”.

On this occasion, Naked Science explains why another infrared telescope is needed after the long-awaited launch of the James Webb and what discoveries can be expected from it.

The SPHEREx infrared space telescope will look into the first second of the existence of the Universe, reveal the secrets of the formation of galaxies, explore water and organic matter in the “cradles of the planets” and much more. And recently, the NASA space agency announced that a much-needed tool has passed the design stage.

“We’re moving from working with computer models to working with real hardware,” says Allen Farrington, SPHEREx Project Manager at NASA’s Jet Propulsion Laboratory.

The design of the spacecraft has been approved in its current form. We have shown that it can be implemented down to the smallest detail. So now we can really start making and joining parts.”

SPHEREx is short for Spectro-Photometer for the History of the Universe and Ices Explorer. The name itself indicates two lines of research.

First, it is the history of the Universe as a whole and its constituent galaxies. Secondly, an overview of the cosmic reserves of water and other substances, without which the existence of life is unthinkable.

Great swelling

What can SPHEREx tell about the universe as a whole? First of all, it will receive a spectrum of 490 million galaxies. The spectrum will allow you to determine the redshift, and thus the distance to the star system. That is, these galaxies will be plotted on a three-dimensional map.

The three-dimensional distribution of galaxies bears the imprint of the history of the universe and the laws governing its development.

The map produced by SPHEREx will be especially good for studying cosmic inflation. This is the name of the hypothetical explosive expansion of space-time in the first fractions of a second after the Big Bang.

The universe is expanding even now, but it is assumed that immediately after the Big Bang this process went on at an unimaginable pace.

The entire part of the universe now accessible to observation has literally swelled from a tiny region of space. During the first 10 −35 seconds after the Big Bang, its volume of this “ball” increased, according to various estimates, by a factor of 1030–1080 . And you thought inflation is when sugar rises in price?

It cannot be said that all cosmologists agree with the inflationary theory. But it links together many properties of the observable Universe, which are difficult to explain otherwise.

For example, this theory explains why the cosmos is so uniform on a large scale. All sufficiently large (from hundreds of millions to billions of light years) regions of the Universe are similar to each other like two drops of water.

Comparing their size with the speed of light (and neither matter nor radiation is transmitted faster), scientists were forced to conclude that each such region had its own independent history.

Why did she come to the same ending everywhere? Yes, because the initial conditions were almost the same everywhere. After all, the beginning of the entire observable universe was laid by a single tiny region of space.

But still, the mass and energy were distributed over this “drop” not quite evenly. Inflation inflated these tiny irregularities, and they gave rise to galaxies and clusters of galaxies. So the three-dimensional distribution of “star islands” captured the history of inflation.

Cosmologists have long debated what caused inflation. According to one hypothesis, it was the birth of particles from vacuum ( the Casimir effect ), superimposed on the curvature of space-time. Other models introduce a special field responsible for inflation, the inflaton. Still others use several inflatons at once.

The distribution maps of galaxies compiled by SPHEREx will make it possible to make a choice in favor of one of these theories. At least, scientists very much hope so.

Noticing the background

Another object of study by SPHEREx is the intergalactic infrared background. This weak radiation has several sources.

Firstly, these are dwarf galaxies, too small and dim to distinguish them individually, but together they give some “flare”. Secondly, these are stellar halos around galaxies. Stellar halos are rarefied clouds of stars that have left their parent galaxy due to some violent processes.

The length of such a halo can reach a million light years. There are other sources of intergalactic infrared “light”, and all of them are somehow connected with the history of the Universe and its constituent galaxies.

Look into the cradle of life

Infrared vision SPHEREx allows you to solve another problem. There are substances that leave a clear spectral trace in the infrared range. First of all, it is water, carbon dioxide and carbon monoxide, and methyl alcohol.

All these compounds are contained in interstellar molecular clouds, the mass of which reaches millions of suns. By earthly standards, these clouds are very rarefied: the distance between neighboring molecules is literally measured in meters.

But compared to the background outer space, these are rather dense clumps of matter. Molecular clouds are stellar maternity hospitals and nurseries. Gravity thickens matter in them, forming protostars and protoplanetary disks. In the future, stars and planets are born from them.

Calculations show that the simplest carbon compounds in molecular and protoplanetary clouds can transform into rather complex organics. These chemical reactions are driven by charged particles from the galaxy and ultraviolet rays from young stars. Experimenters reproduced these processes in laboratories.

The idea suggests itself that protoplanetary organics contributed to the emergence of life on Earth. And if so, the same process could be repeated on other planets.

And yet, we know painfully little about chemical transformations in molecular and protoplanetary clouds. First of all, because observers lack the infrared spectra of these objects. This is where SPHEREx comes to the rescue.

Scanning the celestial sphere, the new telescope will increase the number of available spectra of molecular clouds, protostars and protoplanetary disks by about a hundred times. Such rich observational material should shed new light on the processes that may underlie life.

Census of the Universe

Let’s talk about the device and the observation program of the new telescope.

There are two opposite approaches to space exploration. The first is a careful study of small areas of the sky and individual celestial bodies.

It can be compared with the biographies of prominent personalities. The second is a quick survey of vast areas of the sky, a kind of population census. It is clear that both tasks are important in their own way, but they require different tools.

The recently launched James Webb Infrared Telescope is a prime example of a space biographer. A huge six and a half meter mirror provides it with high resolution: at a wavelength of 1 micrometer, it is able to distinguish details with an angular size of the order of an arc millisecond.

The payoff for such vigilance is a narrow field of view: for example, for the NIRSpec instrument aboard the Webb, it is 3 × 3 arc minutes. It is clear that in no reasonable time he could have surveyed the entire celestial sphere with an area of ​​​​more than 41 thousand square degrees.

SPHEREx, on the contrary, is a “census taker”. The telescope is only 20 centimeters in diameter, so the resolution is a few arcseconds.

Parts with a smaller angular size will merge with each other. But the field of view is very wide: 3.5 × 11 degrees. This allows the telescope to survey the entire celestial sphere four times over the two years of the planned mission.

Webb, with its 132 micromotors driving 18 mirror segments, is the pinnacle of technical sophistication. But the designers of SPHEREx have relied on simplicity.

The telescope has no moving parts (other than the sunscreen, which needs to be deployed once) and cannot switch between viewing modes. This makes the new tool not only reliable, but also relatively inexpensive: it will cost about $400 million, while Webb’s budget is close to ten billion.

The launch of SPHEREx is scheduled for April 2025.

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