Extreme Cosmic Explosions

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2 Extreme Cosmic Explosions

3 Energy 1 Joule = the kinetic energy produced as a small apple (100 grams) falls one meter against Earth's gravity (also, erg = 10-7 J)

4 Explosive Power Stick of Dynamite: Joules

5 Explosive Power Fission nuclear explosion: Joules

6 Explosive Power Hydrogen nuclear explosion: Joules

7 Explosive Power Solar Flare: Joules 0.2 seconds of the sun s full luminosity

8 Image Credit: NASA/SOHO

9 Explosive Power Magnetar Flare: Joules Total solar output for 150,000 years!

10 Explosive Power White dwarf Supernova: Joules Total solar output for roughly its entire lifetime!

11 Explosive Power Core-Collapse Hypernova: Joules Lifetime output of 100 suns!

12 Explosive Power Gamma Ray Burst: Joules Lifetime output of 1000 suns!

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15 What is a Supernova? All stars, even our own peaceful sun, live out an epic struggle between two unfathomable forces: 1. Gravity 2. Pressure

16 What keeps stars from collapsing? The pressure deep inside a star is created by nuclear fusion, burning hydrogen. 10,000,000 or more! The pressure balances the pull of gravity, working like a thermostat to maintain the balance.

17 Stellar Afterlife

18 The life and death of a low-mass star Stars like our sun or smaller live billions or even tens of trillions of years, slowly consuming their hydrogen fuel. They die in a slow puff of gas, forming beautiful smoke rings called Planetary Nebulae.

19 The life and death of a High-mass star Stars more than 8 or 9 times the mass of the sun: very different lives. Live only millions of years, burning their hydrogen rapidly to resist the intense gravity. Start losing the battle to gravity. Solution? Burn heavier elements!

20 High Mass Stars Supergiants evolve rapidly, depleting Hydrogen, then burning successively heavier elements in shells around the core. Star move to the up and right: a Red Supergiant (example: Betelgeuse). Most massive stars: core evolves too quickly, exploding before they become a RSG.

21 Successively heavier elements are burned in layers, heaviest elements at the bottom

22 The final moments When the core of a massive star hits Iron, it s the end of the road. Unlike all elements lighter than iron, iron fusion actually costs energy. At this point, there is no return: the core begins to collapse in a free fall!

23 The final moments When the core of a massive star hits Iron, it s the end of the road. Unlike all elements lighter than iron, iron fusion actually costs energy. At this point, there is no return: the core begins to collapse in a free fall!

24 The final moments When the core of a massive star hits Iron, it s the end of the road. Unlike all elements lighter than iron, iron fusion actually costs energy. At this point, there is no return: the core begins to collapse in a free fall!

25 The final moments When the core of a massive star hits Iron, it s the end of the road. Unlike all elements lighter than iron, iron fusion actually costs energy. At this point, there is no return: the core begins to collapse in a free fall!

26 The final moments Temperatures rise rapidly as the core collapses. Protons and electrons are squeezed together into neutrons: energy is lost, which causes the core to contract faster. A runaway supernova! In a Fraction of a second, the core entirely collapses, moving at 1/4 the speed of light!

27 The final moments Temperatures rise rapidly as the core collapses. Protons and electrons are squeezed together into neutrons: energy is lost, which causes the core to contract faster. A runaway supernova! In a Fraction of a second, the core entirely collapses, moving at 1/4 the speed of light!

28 Cas A In 3D!

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30 The bounce Of the Supernova remants we know (last ~1000 years), most actually exploded more than 10,000 years ago! It took their light that long to reach the earth! What if you missed one? SN 1572

31 The bounce Of the Supernova remants we know (last ~1000 years), most actually exploded more than 10,000 years ago! It took their light that long to reach the earth! What if you missed one?

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