Fermi discovers giant gamma-ray bubbles in the Milky Way (Photo credit: NASA Goddard Photo and Video)
How insignificant are we in the Scheme of Things?
Yo vai bhuma tat sukham,
Nalpe sukham asti,
The Infinite is the satisfying happiness.
In the finite no happiness can ever breathe.
The Infinite alone is the fulfilling happiness.
Na tatra suryo bhati,
Nema vidyuto bhanti;
Kuto ‘yam agnih:
Tam eva bhantam anubhati sarvam
Tasya bhasa sarvam idam vibhati.
There the sun shines not,
nor the moon and the stars,
nor the lightning,
let alone this earthly fire.
Only when illumining Light shines,
everything else shines;
the self-revealing Light illumines
the entire universe.-Upanishds-Indian Philosophy.
“Outside the realm of human vision is an entire electromagnetic spectrum of wonders. Each type of light–from radio waves to gamma-rays–reveals something unique about the universe. Some wavelengths are best for studying black holes; others reveal newborn stars and planets; while others illuminate the earliest years of cosmic history.
NASA has many telescopes “working the wavelengths” up and down the electromagnetic spectrum. One of them, the Fermi Gamma-Ray Telescope orbiting Earth, has just crossed a new electromagnetic frontier….
“Fermi is picking up crazy-energetic photons,” says Dave Thompson, an astrophysicist at NASA’s Goddard Space Flight Center. “And it’s detecting so many of them we’ve been able to produce the first all-sky map of the very high energy universe.”
“This is what the sky looks like near the very edge of the electromagnetic spectrum, between 10 billion and 100 billion electron volts.”
The light we see with human eyes consists of photons with energies in the range 2 to 3 electron volts. The gamma-rays Fermi detects are billions of times more energetic, from 20 million to more than 300 billion electron volts. These gamma-ray photons are so energetic, they cannot be guided by the mirrors and lenses found in ordinary telescopes. Instead Fermi uses a sensor that is more like a Geiger counter than a telescope. If we could wear Fermi’s gamma ray “glasses,” we’d witness powerful bullets of energy – individual gamma rays – from cosmic phenomena such as supermassive black holes and hypernova explosions. The sky would be a frenzy of activity.
Before Fermi was launched in June 2008, there were only four known celestial sources of photons in this energy range. “In 3 years Fermi has found almost 500 more,” says Thompson.
What lies within this new realm?
“Mystery, for one thing,” says Thompson. “About a third of the new sources can’t be clearly linked to any of the known types of objects that produce gamma rays. We have no idea what they are.”
The rest have one thing in common: prodigious energy.
“Among them are super massive black holes called blazars; the seething remnants of supernova explosions; and rapidly rotating neutron stars called pulsars.”
And some of the gamma rays seem to come from the ‘Fermi bubbles’ – giant structures emanating from the Milky Way‘s center and spanning some 20,000 light years above and below the galactic plane.
Exactly how these bubbles formed is another mystery.
How Large is The Universe?
Is The Universe Infinite?