Tag Archives: Big Bang

Astronomers Just Witnessed A Massive Cosmic Explosion… 12 Billion Years After It Happened

Supergiants are massive stars with huge amounts of energy, which causes them to expand rapidly. However, all stars eventually reach a limit, after which the gravity of the core is no longer able to hold the star together.

The explosion that follows is known as a supernova (or sometimes a hypernova, if it’s big enough). As the outer portions of the star explode off, the core collapses upon itself.

Nebulas are the remnants of a supernova explosion. This is the Crab Nebula. Click to enlarge

If a star is large enough, the extreme amount of energy produced by this inward collapse forces the star’s core to release high-energy gamma particles. These gamma bursts are the most powerful event so far discovered in the universe. But just how powerful is that?

Well, in just 10 seconds, these gamma ray bursts release more energy than our Earth’s sun will during the entire 10 billion years of its expected lifespan.

On April 19th, in the Davis Mountains of West Texas, the ROTSE-IIIb telescope (owned by Southern Methodist University in Dallas) detected the rare phenomenon in a corner of the sky.

Click to enlarge

The gamma ray burst, classified as GRB 140419A by NASA’s Gamma-ray Coordinates Network, came from a supernova that happened 12.1 billion years ago, not long after the Big Bang (estimated to have occurred 13.8 billion years ago).

Gamma ray burst have only recently been observed. Not only are they at extremely high frequencies, but they also have the shortest wavelengths on the electromagnetic spectrum, making them more difficult to detect. It wasn’t until the 90s that we created a telescope with the technology to detect gamma radiation.

The discovery was published in Science Daily earlier this month. You can read the full story here.

NOTE: The feature image is an artist rendering of a gamma burst. It is, however, based on detailed scientific study of the event.

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Direct Evidence That the Universe Expanded 100 Trillion TRILLION Times in A Split-Second

Astronomers announced a HUGE discovery yesterday. They claim to have found the first direct evidence to support the Big Bang and the Inflationary Theory of the universe.

For those who aren’t totally familiar with the theory, it basically states that 13.8 billion years ago all the matter in the universe existed in an extremely dense ball of matter (known as the singularity) about the size of a pinhead.

Then this singularity, no longer able to hold itself together, blew apart, expanding by 100 trillion trillion times (that’s 1,000,000,000,000,000,000,000,000 times) in less than the blink of an eye.

Here’s a nice graphic illustrating inflationary theory (the top numbers are the time after the Big Bang, the bottom numbers the average temperature of the universe)

Click to enlarge

Scientists theorized that this explosion was so massive and violent that it ripped apart space itself. Einstein theorized that if this were the case, we would be able to observe gravitational waves (which squeeze and stretch space) that were left over from the Big Bang.

So how did the scientists know they had observed gravitational waves? Well, these waves produce a very distinct “swirly” pattern (like the ones in the image below) in polarized light, known as “B-mode” polarization. Polarization is when light waves are distorted from their original shape.

B-mode polarization fractions of a second after the Big Bang (Image: BICEP2 Project)
Types of light polarization

There have been a number of discoveries in the past which pointed indirectly to the Big Bang and expansion, such as the discovery of cosmic microwave background radiation, but scientists consider this discovery the first direct evidence supporting the inflationary theory.

Read the full story from Space Industry News here.

Chair of the Astronomy Department at Harvard Says Other Complex Life in Universe Very Possible

Abraham (Avi) Loeb an American/Israeli theoretical physicist who works on astrophysics and cosmology and is Chair of the Astronomy Department at Harvard says that “it’s quite possible that life is everywhere and we are the late-comers”. Today Forbes released an article that summarizes a paper submitted by Avi Loeb to the journal of Astrobiology. The entire article can be viewed below.

The following passage comes directly from Forbes (Note I have bolded certain key points)

   The evolution of complex life in the universe has, heretofore, thought to have been quite a long slog.

But in a paper submitted to the journal Astrobiology, theoretical cosmologist Avi Loeb argues that some form of complex life may have arisen within the first billion years of our universe’s existence.

Loeb, Chair of the Astronomy Department at Harvard, says that some fraction of the cosmos’ first so-called Population III stars may have produced supernovae that seeded the early cosmos with large amounts of metals, like iron. Such heavy elements, Loeb notes, are crucial when forming terrestrial planets like our own.

These first stars — thought to on average have been some 100 times more massive than our sun — likely had hydrogen-burning lifetimes of only 3 million years. Yet Loeb says a follow-on population of Population II stars that formed within these very first stars’ metal-rich vicinity, could have spawned earthlike planets, some fraction of which may have harbored complex life.

“These were stellar “islands” enriched by heavy elements where you could make planets,” said Loeb. “But most of the early universe either had pristine [hydrogen] gas or low metallicity gas.”

The Cosmic Microwave Background (CMB), relic radiation leftover from the Big Bang, was roughly room temperature when the universe was only 15 million years old.

A rocky planet at such early times, wouldn’t have needed the warmth of its parent star, but Loeb says could simply have bathed in the CMB’s radiation, which for some 3 million years at least could have allowed for planetary liquid water and, in principle, the chemistry of life.

And if that prospect isn’t tantalizing enough, Loeb says conceivably tens of millions of years after the Big Bang, Population II stars could have also had metal-rich proto-planetary disks capable of forming earth-like planets.

These longer-lived Population II stars would have provided stable long-term conditions for these young earths and may have led to life as we know it literally near the dawn of time.

Theoretical Cosmologist Avi Loeb.  Credit:  CfA Public Affairs

Cosmologist Avi Loeb

In his paper Loeb also says that even in a cosmos that had an initial high value cosmological constant, or energy density of the spacetime vacuum, complex life would have still had time to evolve within the first one billion or so years of the universe’s ex

istence. That is, before this accelerating vacuum energy caused space to expand so rapidly that gravity could not have done its work and galaxies like our Milky Way — rife with stars and planets like our own — could not have formed.

To date, however, the standard paradigm for the evolution of intelligent life in the universe is that if it’s out there, it’s probably only been around for the last 6 billion years, or about a billion years after the peak of cosmic carbon production.

But what if life did evolve on an earth-like planet circling an early Population II star?
One born only 50 million years after the Big Bang?

If it vectored into intelligence that somehow persisted over much of the universe’s 13.8 billion-year history, by now such an ancient civilization’s technology would arguably be nothing short of “godlike.”

firststars

Simulated Image of the Universe’s first Stars

“The picture that we have of the [early] universe is that the cosmos is sort of dead,” said Loeb. “But it’s quite possible that life is everywhere and we are the late-comers.”

 

Most Distant (And Therefore Oldest) Galaxy Discovered

A team of scientists from the University of Texas and Texas A&M put aside old football rivalries in the name of science to discover the furthest galaxy ever seen from Earth (z8_GND_5296 is its catalog name, it has yet to be given a common name). Because of the fact that 1. the universe is always expanding and 2. light travels at a finite speed, the massive distance between us and the galaxy means that what we are seeing is the galaxy 13 billion years ago- that is how long it has taken for the light of that galaxy to reach us. So the researchers get to see a snapshot of what the universe looked like when it was only about 700 million years old (it’s around 13.8 billion years old now).

Here is what the galaxy looks like through the Hubble Telescope:

The galaxy appears red because of the phenomenon known as “red-shift” in which the blue light emitted by stars get shifted toward redder colors because of the expansion of the universe and its large distance from Earth. The image at the top is an artist rendition of what the galaxy looks like up close.

(to read the full story, click the link below)

Most Distant (And Therefore Oldest) Galaxy Discovered