- 3208 - HUBBLE DEEP FIELD - surveying deep space uncovered many remote galaxies and more galaxies in between. The galaxies vary in shape, size and color. We can see how they changed through time. With the Hubble Deep Field, we reach back nearly to the time when galaxies emerged from the chaos of the Big Bang.
------------------- 3208 - HUBBLE DEEP FIELD - surveying deep space?
- In 1995, Hubble stared at a tiny and nearly empty patch of sky near the Big Dipper for 10 straight days. This was a long time exposure for the telescopes camera. The telescope gathered all the light it could, slowly building a picture. The “Hubble Deep Field” emerged and revealed galaxies fainter than had ever been seen before. The light from some of these has traveled for 10,000,000,000 years to reach us.
-
- It showed us a sliver of the early universe, from long before our sun was born. This is really a three-dimensional picture, a cosmic core sample. The results in the image are 3,000 galaxies, large and small, shapely and amorphous, burning in the depths of space.
-
- There are a few foreground stars, many remote galaxies and more galaxies in between. The galaxies vary in shape, size and color. We can see how they changed through time. With the Hubble Deep Field, we reach back nearly to the time when galaxies emerged from the chaos of the Big Bang.
-
- What we are seeing with is very, very old light that has taken billions of years of travel to reach us. And, it was traveling 186,000 miles per second.
-
- Since then Hubble has teamed up with other observatories to examine small patches of the sky in high resolution with long exposures and multiple wavelengths. Surveys like the “Hubble Ultra Deep Field“, and the “Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey” have provided pictures of vast, deep collections of galaxies. Some of these galaxies existed when the universe was less than a billion years old.
-
- In 2014, astronomers released the most colorful and comprehensive picture of the evolving universe ever captured by Hubble. The observation, called the “Ultraviolet Coverage of the Hubble Ultra Deep Field“, provides the missing link in star formation.
-
- Using ultraviolet light, astronomers combined the full range of colors available to Hubble, stretching all the way from ultraviolet to near-infrared light. Ultraviolet light comes from the hottest, largest and youngest stars.
-
- By observing at these wavelengths, researchers get a direct look at which galaxies are forming stars and where the stars are forming within those galaxies. Studying the ultraviolet images of galaxies in this intermediate time period enables astronomers to understand how galaxies grew in size by forming small collections of very hot stars. Because Earth’s atmosphere filters most ultraviolet light, this work can only be accomplished with a space-based telescope.
-
- The image was made from 841 orbits of telescope viewing time. It contains approximately 10,000 galaxies, extending back in time to within a few hundred million years of the big bang.
-
- Hubble can see even farther back in time by using gravitational lensing to find more distant galaxies that formed even earlier in the universe, such as in the CLASH survey and Frontier Fields. With its powerful infrared vision, the James Webb Space Telescope will see even farther back in time.
-
- The most extensive cosmological survey to date, the Dark Energy Survey (DES) took place over 6 years from 2013 to 2019, and looked at over 1/8th of the night sky for a total of 758 nights.
-
- Observations were done with the Victor M Blanco telescope at Cerro Tololo Inter-American Observatory in Chile. Measuring 4 meters in width, the Blanco telescope has a resolution of 570 mega pixels, almost 50 times as much as a standard iPhone camera.
-
- All that observational power is great to collect data, but the scientists need to know what to do with it when collected. The goal of the survey was to “quantify the distribution of dark matter and the effect of dark energy. These two poorly understood cosmic features make up 95% of all the known “stuff” in the universe.
-
- DES provided more insight that ever before into some characteristics of these little understood phenomena, called dark matter. In particular, two cosmological features were central to the survey’s efforts. The first was the “cosmic web”, while the second were “weak gravitational lenses“.
-
- The cosmic web is used to describe the structure of galaxies. These massive clusters of gravitationally bound stars aren’t randomly distributed, as one might assume if the universe was all started from the same state. They form a pattern, with clumps of galaxies banding together to form galaxy clusters.
-
- Cosmologists normally attribute those clumped up areas to the presence of higher densities of “dark matter” and, therefore, gravity. Mapping where they occur in space provides insight into what areas of the galaxy might feature high concentrations of dark matter to study.
-
- Results from universe growth models can then be compared to the cosmic web as a way to check their accuracy in predicting how the universe actually turned out. Clustering isn’t the only way to detect dark matter though. DES scientists also utilized a well-studied cosmological phenomena called “gravitational lensing“.
-
-This effect happens when light is bent around areas of high gravity, which pockets of dark matter certainly are. Strong gravitational lensing, such as that around blackholes, is a common enough feature of cosmology.
-
- “Weak gravitational lensing” doesn’t have quite as much visual impact, but it does provide more insight into that important map of dark matter and dark energy.
-
- Redshifting is a feature of astronomical observations where things that are far away and getting further away appear to have the light they emit shifted to the red side of the light spectrum.
-
- The DES team also analyzed a number of other phenomena, which included baryonic acoustic oscillations, frequency measurements for massive galaxy clusters, and calculations of some of the features of Type 1a supernovae captured in the survey.
-
- Survey results from the DES fit well with the predicted model that is used to map the universe from the beginning of time. In fact, it contradicts previous claims that there was a few percentage difference between the observed universe and the predicted one.
-
- But the team has only analyzed half the data, so the other half is expected to add even more detail to the picture of dark energy and dark matter. In addition, new surveys using new instruments, such as the “Vera Rubin Observatory“, are already planned.
-
------------------------------- Other Reviews availsable:
-
- 3170 - HUBBLE - deep field discoveries? The Hubble Space Telescope was launched in 1990. It weighed 22,500 pounds, 14 feet in diameter, 43 feet long, and orbits at 300 miles elevation. In 1993 a 94 inch mirror was repaired to solve some resolution problems. Cost of the program was $1,400,000,000 dollars.
-
- 2814 - HUBBLE - tests to detect exoplanets life? Astronomers have been using a variety of ground- and space-based telescopes to analyze how the ingredients of Earth's atmosphere look from space, using our planet as a proxy for studying extrasolar planets' atmospheres. They hope to eventually compare Earth's atmospheric composition with those of other worlds to note similarities and differences.
-
- 2736 - HUBBLE - 30 years of astronomy? - The Hubble Space Telescope launched on the 24th of April, 30 years ago. One of the primary reasons for the Hubble telescope’s longevity is that it can be serviced and improved with new observational instruments through Space Shuttle visits.
-
- 1770 - The Hubble Space Telescope is celebrating 25 years of space astronomy. One of its greatest discoveries in 1998 was that gravitational attraction of all the matter in the Universe was not causing cosmic expansion to slow down. Quite the opposite, Hubble’s view of the most distant supernovae explosions confirmed that cosmic expansion was accelerating
-
- 1179 - What has Hubble Taught Us? The Hubble Space Telescope has been sending us astronomical images for over 20 years. The telescope was launched in the Discovery Space Shuttle in April, 1990. Astronomers have been studying Hubble’s images, and the data that created them, and have written over 7,000 scientific papers to date. Let’s look at some of the discoveries that have been made by this telescope orbiting the Earth.
-
- 1173 - The Hubble Deep Field space telescope image is one of the most amazing discoveries in all of astronomy. The space telescope stares at a single, small spot in the darkest part of the sky. It stares for the longest time to get the longest time exposure and to collect photons that are as faint as possible.
-
- 1047 - The Hubble Space Telescope took its pictures using a very long time exposure lasting 10 days or more. The Hubble camera used CCD’s, charge coupled devices, that can collect photons over that entire time of exposure. Our eyes can not do this. Photons fire nerve cells in the back of our eyes and send the image to the brain. We do not have the ability to collect the photons until the image gets bright enough to see. The Hubble camera has much greater sensitivity and can see very faint objects accumulating photons over a long period of time. Faint objects are very far away and strange things happen while the light is traveling those distances.
-
- 857 - Hubble Deep Field Discoveries. Everyone has heard of and seen images of the Hubble Deep Field. These images were created by the Hubble Space Telescope staring at a single spot in the sky and taking a very long time exposure picture. If you missed it go to Sky in Google Earth to get the picture.
-
- 772 - Hubble Space Telescope. This is the 17th anniversary of the Hubble Space Telescope. It was launched April 24, 1990. I have collected some 8 3-ring binders, full of Hubble pictures. The discoveries using Hubble’s instruments have made astronomy and physics a frontier of amazement for me.
-
- July 4, 2021 HUBBLE DEEP FIELD - surveying deep space? 3208
----------------------------------------------------------------------------------------
----- Comments appreciated and Pass it on to whomever is interested. ----
--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for copies or Index of all reviews
--- to: ------ jamesdetrick@comcast.net ------ “Jim Detrick” -----------
--------------------- --- Monday, July 5, 2021 ---------------------------
No comments:
Post a Comment