The Universe 800 Million Years After the Big Bang: An Epoch of Massive Stars (3-D VIDEO)

Astronomers have completed conducting the broadest survey to date of galaxies from about 800 million years after the Big Bang. They found 22 early galaxies and confirmed the age of one by its characteristic hydrogen signature at 787 million years post Big Bang. The finding is the first age-confirmation of a so-called dropout galaxy at that distant time and pinpoints when an era called the reionization epoch likely began.

 
Astronomers have long wondered whether the universe underwent reionization instantaneously or gradually over time, but more importantly, they have tried to isolate when the universe began reionization. Galaxy density and brightness measurements are key to calculating star-formation rates, which tell a lot about what happened when. The astronomers looked at star-formation rates and the rate at which hydrogen was ionized.

Using data from their study and others, they determined that the star-formation rates were dramatically lower from 800 million years to about one billion years after the Big Bang, than thereafter. Accordingly, they calculated that the rate of ionization would be very slow during this early time, because of this low star-formation rate.

“We were really surprised that the rate of ionization seems so low, which would constitute a contradiction with the claim of NASA’s WMAP satellite. It concluded that reionization started no later than 600 million years after the Big Bang,” remarked Ouchi. “We think this riddle might be explained by more efficient ionizing photon production rates in early galaxies. The formation of massive stars may have been much more vigorous then than in today’s galaxies. Fewer, massive stars produce more ionizing photons than many smaller stars,” he explained.

With recent technological advancements, such as the Wide-Field Camera 3 on the Hubble Space Telescope, there has been an explosion of research of the reionization period, the farthest back in time that astronomers can observe.

The Big Bang, 13.7 billion years ago, created a hot, murky universe. Some 400,000 years later, temperatures cooled, electrons and protons joined to form neutral hydrogen, and the murk cleared. Some time before 1 billion years after the Big Bang, neutral hydrogen began to form stars in the first galaxies, which radiated energy and changed the hydrogen back to being ionized. Although not the thick plasma soup of the earlier period just after the Big Bang, this star formation started the reionization epoch. Astronomers know that this era ended about 1 billion years after the Big Bang, but when it began has eluded them and intrigued researchers like lead author Masami Ouchi of the Carnegie Observatories.

The U.S. and Japanese team led by Ouchi used a technique for finding these extremely distant galaxies. “We look for ‘dropout’ galaxies,” explained Ouchi. “We use progressively redder filters that reveal increasing wavelengths of light and watch which galaxies disappear from or ‘dropout’ of images made using those filters. Older, more distant galaxies ‘dropout’ of progressively redder filters and the specific wavelengths can tell us the galaxies’ distance and age. What makes this study different is that we surveyed an area that is over 100 times larger than previous ones and, as a result, had a larger sample of early galaxies (22) than past surveys. Plus, we were able to confirm one galaxy’s age,” he continued. “Since all the galaxies were found using the same dropout technique, they are likely to be the same age.”

It helps to put things in perspective here on our frenetic little planet with a look at this extraordinarily powerful and moving video of the Hubble Space Telescope mapping of the Universe, whose known size is 78 billion light years across.

The video of the images is the equivalent of using a "time machine" to look into the past to witness the early formation of galaxies, perhaps less than one billion years after the universe's birth in the Big Bang.

The Hubble Deep Field video below video includes mankind's deepest, most detailed optical view of the universe. One of the stunning images was assembled from 342 separate exposures taken with the Wide Field and Planetary Camera 2 (WFPC2) for ten consecutive days.

Representing a narrow "keyhole" view stretching to the visible horizon of the universe, the HDF image covers a speck of the sky only about the width of a dime located 75 feet away. Though the field is a very small sample of the heavens, it is considered representative of the typical distribution of galaxies in space because the universe, statistically, looks largely the same in all directions. Gazing into this small field, Hubble uncovered a bewildering assortment of at least 1,500 galaxies at various stages of evolution.

Most of the galaxies are so faint (nearly 30th magnitude or about four-billion times fainter than can be seen by the human eye) they have never before been seen by even the largest telescopes. Some fraction of the galaxies in this menagerie probably date back to nearly the beginning of the universe.

"The variety of galaxies we see is amazing. In time these Hubble data could turn out to be the double helix of galaxy formation. We are clearly seeing some of the galaxies as they were more than ten billion years ago, in the process of formation," said Robert Williams, Director of the Space Telescope Science Institute Baltimore, Maryland. "As the images have come up on our screens, we have not been able to keep from wondering if we might somehow be seeing our own origins in all of this."

Essentially a narrow, deep "core sample" of sky, the HDF is analogous to a geologic core sample of the Earth's crust. Just as a terrestrial core sample is a history of events which took place as Earth's surface evolved, the HDF image contains information about the universe at many different stages in time. Unlike a geologic sample though, it is not clear what galaxies are nearby and therefore old, and what fraction are very distant and therefore existed when the universe was newborn. "It's like looking down a long tube and seeing all the galaxies along that line of sight. They're all stacked up against one another in this picture and the challenge now is to disentangle them," said Mark Dickinson of the HDF team.

Nearly a year of preparation preceded the observation. The HDF team selected a piece of sky near the handle of the Big Dipper (part of the northern circumpolar constellation Ursa Major, the Great Bear). The field is far from the plane of our Galaxy and so is "uncluttered" of nearby objects, such as foreground stars. The field provides a "peephole" out of the galaxy that allows for a clear view all the way to the horizon of the universe.

You may have asked, "How can the universe be 78 billion light years across when the age of the universe is only about 13 billion years?"

How can something be larger than then distance travelled at the speed of light? Since light from the beginning of the universe has only had 13 billion years to travel (not 78 billion), then shouldn't the universe be only 13 billion light years across? That's a pretty intuitive thought.

But it doesn't take into account that the entire universe itself is also expanding. When a photon of light leaves it's point of origin, it does so at the speed of light, so in a universe that doesn't expand, a photon traveling for 13 billion years traverses 13 billion light years.

In a universe that does expand, all of the distance covered by the photon gets increased by a scale factor equal to the rate of expansion of the universe.

Casey Kazan via The Carnegie Institution

http://www.ciw.edu/news/dropouts_pinpoint_earliest_galaxies

Comments

[claudio]

Very good pictures from Hubble.

However the theory that the universe is some "78 billion light years across" is rather surprising.

I would guess that these scientists are overevaluating the capability of measuring distances via the 'red shift'.

FAQ : is the expansion rate superior to the speed of light ?? and if so what can prove that in addition to the red shift ??

Too much 'human math' does NOT help our understanding of the Physics , nor it does computer modeling and simulation.

Regards

[Ryan Cybulski]

Your title incorrectly says "800 Billion Years After the Big Bang" instead of "800 Million Years After the Big Bang". That left me very confused for a few seconds.

[Andrew T]

I agree with Ryan, the universe 800 billion years after the BB will look very different from the one just 800 million years old. In particular, in 800 billion years there will be few if any massive stars. Anything luminous will in all likelihood be a long-lived red dwarf, or the occasional neutron star.

[buzz]

In reply to claudio's claims:"human math doesn't help our understanding of the physics, nor it does computer modeling and simulation.". Such statements can only be made by someone who has clearly no idea to how the simulations were created and how math and physics go hand in hand. Now, to answer your question on the expansion rate. It was calculated by Edwin Powell Hubble himself. had a value of 500 km/s/Mpc,back then, and is now called the Hubble-Humason constant. In the future, before making other uneducated claims, be more considerate, after all, the telescope that brought you these stunning images was named after him.

[The Astronomist]

I discussed the science of the HUDF in a blog post months ago: Hubble Ultra Deep Field Part II, but of course what would I know because I was considering the universe some 800 million years after the big bang, not 800 billion.

[haha, read your bible]

You guys all believe we came from a big bang, cosmic soup, and a rock. There is actual proof that the earth is about 7000 years old, yes you read correct 7000 years.

God is greater then any one of you! visit www.drdino.com

[G]

Don't bother changing the title, I don't think anyone noticed.
Article itself is very interesting.

@haha,read your bible - My science is better than your science.

[Geoff Wales]

"You guys all believe we came from a big bang, cosmic soup, and a rock."

I don't 'believe' science. Nor do good scientists. They try to keep an open mind. When enough scientists agree on something, I tend to accept it, coz OMG they iz smarter than me.

How about you, how do you process information?

OT: When are the editors going to correct the 800 'Billion' years typo?

[EvilCosmicMonkeyfrom Knoxville]

With some folks bringing religion into science ( re.: remark about " Big Bang, cosmic soup, & a rock " ) is like mixing matter & anti - matter or tossed salads & scrambled eggs.

The Earth & Universe is WAY older than 7,000 years old. That fallacy came from Bishop Usher, " haha ".

Sit back & enjoy the video with the rest of us. God created science to understand the Universe that He / She ( ? ) made.

[Galaxy1]

"How can the universe be 78 billion light years across when the age of the universe is only about 13 billion years?"

I like to think of this analogy in a non expanding universe you are walking on flat ground. In an expanding universe you are walking on top of a flat escalator (like at the airport) that is moving as well (expanding). So you get farther even though you are walking the same speed as without the escalator.

[Neil Graham]

Since a year is defined as the time it takes for our planet to journey around its sun and our planet is 4.5 billion years old, how can we reasonably talk of 'years' before 4.5 billion?

[e cigarette]

Damn that is one seriously amazing picture. We are sooooo small.

[Geoff Wales]

A year is just a convenient unit of time we use.

The real size of the universe may be impossible to measure, because of the absolute limits of our observation. If you follow the hypersphere model we earthlings have a cone of maximum theoretical observation* that shrinks down (going back in time) almost to the centre, ie to the Big Bang singularity. This is 'our' observable universe. The surface of the hypersphere is the 'universal' present, if such a thing can be said to exist.

The size of the hypersphere can never be measured for the reason that it stretches beyond our cone (a circle at the surface), and according to at least one version of Inflationary Theory may be so vast that the maximum diameter of our cone would be incredibly tiny. I like to imagine a full stop on the edge of our solar system to get a feel for how big the universe may really be. :)

*The field of our observation expands as the universe expands, but remains proportional to the surface area. As the hypersphere grows 'our' observable universe grows with it, like a circle on the surface of a balloon. Connect the circles through time, and you have a cone.

[EvilCosmicMonkeyfrom Knoxville]

A / V like this just begins to scratch the surface of how big, beautiful & mysterious our universe is.

& we've barely begun to dampen our toes in the cosmic ocean, to crib from Carl Sagan.

[Freedomcloud]

Ok I tried to imagine that with our sun, being so big, there are a lot of stars in our galaxy way bigger, then the galaxy itself has over a billion stars, then adding over 100 billion galaxies that have over a billions tars each and probably suns way bigger than most of our suns in our galaxy... I think I just fried myself.

[water ionizers]

The water that has a large number of H+ ions is acidic and the water that has a predominance of OH- ions is alkaline. Because most people accrue too much acid in their body over years of dietary and lifestyle patterns, they need to balance their body pH to move the body more toward the alkaline side of the pH spectrum.