Looking to the future of Astronomy: umbrella star, that’s your world

25 years ago, if you asked an astronomer if there were planets revolving around a sun like star, the answer you would get would be “possible,” but there is no example. Five years ago, if you asked astronomers if there were rocky earth like planets around sun like stars, they might have told you, “it’s possible,” but they can’t give an example either. Now, however, in 2016, we have found more than 2000 confirmed planets in other star systems, including hundreds of rocky planets, of which about 8-12 are in suitable space for liquid water and the potential for life. Without advanced technology, all we can do is speculate. But if we can capture and analyze light from other rocky planets, we may be able to look for signs of life in them: < / P > < p > imagine that all the information we want to know is contained in thousands of photons from planets that are not so different from the earth. When the earth moves in orbit, we can see different proportions of the ocean and land, and measure the area covered by liquid and solid respectively. By collecting the light reflected from the planet’s atmosphere, we can identify the characteristics of spectral absorption and the proportions of various components in the air, such as nitrogen, oxygen, water vapor and methane, and thus determine whether the planet is habitable. By observing the earth in different orbital positions, that is, in different seasons, we can find that the continental block has changed from lush to grayish brown, and from grayish brown to covered by ice and snow, and goes on and on. < / P > < p > the key is to collect the light from the planet and not let the light be submerged by the light of the star. You might think that we can do this easily just by using a coronameter to shield the stars. It is true that coronameters play an important role in astronomical research, but wave like light has an unfortunate characteristic that it diffracts when it encounters an object, even when it encounters a coronagraph. If the planet’s orbit is not deflected by billions of times as much light from the planet’s orbit as it would have been if the planet’s light hadn’t been deflected a few billion times. However, we have an amazing technique that can help us completely block the light from the stars by placing an optical object of the right size far away from the telescope lens. In other words, the solution to dim planets does not depend on more advanced telescopes, but on special light blocking devices, just as the moon blocks the sun during a total solar eclipse. However, the umbrella stars are not circular and are not as large as the moon in angle. We’re looking for a planet that is only 36000 parts of a degree away from its star. It also means that we only need it to occupy a small area of the telescope. An umbrella star like this must have the following three characteristics: < / P > < p > it must have a special shape, not a circle, but a mathematical model called super Gaussian surface. This model has a special property: when the star’s rays deflect at the edge of its surface, these rays will entangle and interfere with each other destructively. As a result, the star’s light is reduced by as much as 1010 times, allowing the planets to emerge. Due to the optical property of Fresnel number, the umbrella star must be very large and extremely far away. In general, it needs to be angled. If it’s really far away, its Fresnel number will be even greater. Large values will help to reduce the amount of light escaping, so it is best to create a larger and extremely remote umbrella star to reduce the interference caused by the light from the outside star. < / P > < p > finally, it must match the line of sight of the telescope precisely. This means that it has to have its own propulsion and stabilization system, so that it can be well synchronized with the connected telescopes. < / P > < p > for Hubble class telescopes, such as NASA’s planned wide field infrared telescope, it will require a 35 meter long umbrella star with a wingspan. The sunshade will fly up to 40000 kilometers from the 2.4 meter wide telescope, about one earth circumference. < / P > < p > makes telescopes, umbrella stars and stars line up in a perfect line, thus blocking the light of stars and revealing planets directly, eliminating interference from stars. < / P > < p > even so, if we launch the umbrella with NASA’s 10-year flagship mission wide field infrared telescope in the 1920s, we will be able to collect data on all rocky planets around the 30 or so stars closest to earth. For just a billion dollars, you can get a glimpse of the atmosphere of a rocky planet. < / P > < p > you may wonder if this works because you should. As part of the proof of concept phase, the scientists built a model of the umbrella star and took a picture of Vega, one of the brightest planets in the night sky, without the umbrella Star: < / P > < p > while taking another picture, the scientists placed a model of the umbrella star at a suitable distance from the telescope. The first image is saturated after only one second of exposure, however, the second image only gets the following image after 20 minutes: < / P > < p > after this simple experiment, Vega’s light has been weakened by more than one billion orders of magnitude, and many stars that have never been seen before have been revealed. By using the new concept of umbrella stars to block the light of stars, we can observe objects closer to the stars than ever before. < / P > < p > What about the next step? We will put the sunshade in orbit and make it work with Hubble and even higher-level optical space telescopes. If successful, for the first time, we will be able to see for the first time the light emitted directly by dozens of rocky planets, including the spectra of planets’ rotation and rotation in orbit. < / P > < p > for the first time in history, we will be able to actually assess whether there are rocky planets with similar or different biomarkers to the earth in other star systems, even in the habitable zones of other star systems. The journey of pursuing life in the universe has just begun. The future of astronomy is closely related to the pursuit of life. Moreover, we have the ability to make good things happen! Skip to content

Author: zmhuaxia