Looking at the Most Distant Galaxy in the Universe


Background

The Hubble Space Telescope was launched into space in 1990. Due to a technical problem that occurred during its installation, earlier images taken by the space telescope had some deformities in them. This problem was resolved in 1993. NASA published the first picture taken by the Hubble Space telescope back in January 1994.

The First Image taken by the Hubble Space Telescope Courtesy: Hubble Site

The First Image taken by the Hubble Space Telescope
Courtesy: The Hubble Site

Since then, the Hubble Space Telescope has been capturing a significant number of images of various celestial objects including stars and galaxies, which help to understand how our universe, galaxies and stars behave at a large-scale.

NASA’s Spitzer Space Telescope was launched in 2003, primarily aiming to do infrared observing. Infrared light is a form of electromagnetic radiation. As most of the infrared radiation gets absorbed by the earth’s atmosphere, the Spitzer Space Telescope was also launched into space to make observations in the infrared spectrum of the electromagnetic radiations.

Let’s remind ourselves a few definitions before we go farther. Stars are primarily composed of hydrogen, which fuses into helium. During this process energy is released. It causes the stars to shine in the night sky. Our sun is a star and we reside in a galaxy named the Milky Way. Assuming the universe is finite, the scientists found that the early universe was a very different place than the present observable universe. Right after the Big Bang, the universe was immensely hot. Eventually, the universe cooled off, and hydrogen atoms were formed.

News Headline

Last November, NASA announced that a joint collaboration between the Hubble Space Telescope and the Spitzer Space Telescope discovered the most distant galaxy in the observable universe. The galaxy was cataloged as MACS0647-JD. Surely, it does not have any fancy name like our own galaxy or our neighboring galaxy, Andromeda.

The Distant Galaxy  Image Courtesy: The Hubble Site

The Distant Galaxy
Image Courtesy: The Hubble Site

In astronomy, looking at a distant object is simply analogous to looking back in time. Astronomers found that the most distant galaxy was formed when the universe was only about 430 million years old; whereas, currently the universe is about 13.7 billion years old.

News Analysis

In a research paper published by Coe et al. from the Space Telescope Science Institute, the researchers claimed that their team found the most distant galaxy in our observable universe. The visual images were obtained using the Wide Field Camera 3 (WFC3) and the Advanced Camera for Surveys (ACS). For the infrared part, the Spitzer Space Telescope’s InfraRed Array Camera (IRAC) was exposed over 5 hours. As the object is really far away, the exposure time increases.

Importance

This galaxy was directly viewed because gravitational lensing helped us to see this distant celestial object. In principle, light can be bent by gravity. In the case of this distant object, there are numerous massive sources lie in between the light source and us. One can consider other galaxies and stars to be the intermediate massive sources, which bend light.These massive sources can also magnify the source you are aiming to look at. This phenomenon is known as gravitational lensing. The distant galaxy is visible to us because the intermediate mass-sources bend light and magnify its real size.

Finding this galaxy successfully testified various models on gravitational redshift. When a fast paced object moves towards the observer, its frequency gets shorter and the wavelength gets compressed. Blue light has a shorter wavelength than red light. That is why blue shift refers to an object moving towards us with a high speed. On the other hand, when an object moves away from us, it exhibits a red shift. The wavelength gets stretched away. Red light has a longer wavelength than blue light. In reality, gravity has the same effect on mass-less photons or light particles. By testing various models for gravitational redshifts, researchers concluded that this distant object first emitted light from it when the universe was only about 430 million years old. This observed galaxy had a really high red shift.

Researchers think that this distant object can be studied using the futuristic James Webb Space Telescope. This will reveal many unknown facts about the formation of big structures such as how primordial galaxies and stars shape our universe.

Prospects in Observational Astronomy


Values in Observational Astronomy

In the early seventeenth century, Italian astronomer Galileo Galilei first used the telescope to look at the celestial objects. He made several important observations including phases of the Venus and the Jovian moons, which changed the contemporary worldview. The geocentric model of the solar system was challenged by his observations. Later, the heliocentric model was accepted. As time progressed, observational astronomy became popular in Europe. The Dutch and the English pioneered in the field of big optical telescopes. Among them, Sir William Herschel built a 20 feet long reflector one. He also proposed a theory on how big the visual universe is and he created a sky atlas of the Milky Way.

Herschel's 20 feel long Telescope, Courtesy: Royal Astronomical Society

Herschel’s 20 feel long Telescope                            Courtesy: Royal Astronomical Society

Purpose

Later in the nineteenth century, observational astronomy research geared toward the United States of America. A new group of professional astronomers emerged during this period. For example, the Smithsonian Astrophysical Observatory, the Astronomical Society of the Pacific, the American Astronomical Society, the American Association of Variable Star Observers were founded then. Later in the twentieth century, Edwin Powell Hubble discovered that the farther a galaxy appears, the faster it recedes from us. This is known as Hubble’s law. In the last decade, the Hubble Space Telescope observed the farthest object in our observable universe.

Using the Wide Field Camera 3, the Hubble Space Telescope observed the farthest object in the universeCourtesy: HubbleSite.org

Using the Wide Field Camera 3, the Hubble Space Telescope observed the farthest object in the universe.
Courtesy: HubbleSite.org

Importance

Observational Astronomy has been playing a great role in unfolding the mystery of the universe. Professional astronomers from all over the world are working as a group in various projects. The rest of the blogpost will highlight three major observational projects, which aim to reveal the formation and evolution of the universe.

The American Association of Variable Star Observers (AAVSO) undertook the APASS (the AAVSO Photometric All-Sky Survey) back in 2010. This ambitious project aims to prepare a sky atlas of the entire northern and southern hemisphere in five different optical filters. This project will include stars which have the apparent magnitude 17 or higher.

Readers probably figured out that today’s research work involves collaboration among scientists at the highest level. So far, observational astronomy projects discussed in this blog focused mainly on observations done in the visual wavelength of the spectrum. Since late 1960s astronomical observations have been made in the entire electromagnetic spectrum of the light, such as X-rays, gamma-rays, microwaves, radio waves, etc. The NASA’s James Webb Space telescope is a visionary project, which will capture images in the IR (infrared) band of the spectrum. This project was threatened due to budget cut. The Webb telescope will be funded by the NASA, the Canadian Space Agency (CSA), and the European Space Agency (ESA).

The last project mentioned here aims to do radio astronomy at a massive scale. The Square Kilometre Array project has been considered to be the largest radio astronomical telescope, which will be built in Australia and South Africa. Scientists across the Asia-Pacific nations, China, India, the UK, Sweden, Italy and Germany are hoping to reveal the mystery of galaxy formation, super massive black holes and many more through this project.

Readers can see that astronomy is an empirical science. People often ask whether these researches have any direct implication in real life. To address that concern, we can think of how the telecommunication science has been improved in the last decade. We cannot simply ignore the fact of having access to better computing and software relies on astronomers’ endless effort in developing algorithms, which analyze a huge data set efficiently. Astronomers inspire and challenge the computer scientists and it is because of the research that we have cell phone cameras, which can take pictures and transfer them to another device instantaneously.