Northern Lights Possible Tonight March 14-15 / Farewell Mr. Hawking

Soft rays streak the northern sky from near Duluth last September. Bob King

“Et tu, Brute?” It’s a portentous overnight for the aurora since midnight marks March 15, the Ides of March. You’ll recall that was the day in 44 B.C. when Caesar was stabbed to death by a group of Roman senators including his friend Brutus. The Latin quote, which translates as “And you, Brutus?”, comes from Shakespeare’s play Julius Caesar. By the way, one knows for certain what if anything Caesar said when so betrayed.

Beware of the aurora, I say. It can betray, too. With that in mind, the space weather forecast calls for a minor G1 storm tonight roughly between the hours of 10 p.m. and 1 a.m. Central time. Minor usually means the aurora is restricted to the northern states, Canada and northern Europe, but you never know. I’ve seen minor storms become strong ones or not materialize at all. Often, the aurora does make an appearance but earlier or later than predicted.

If you live anywhere in the northern half of the U.S. and it’s clear tonight, face north when it’s dark and check for activity. You’ll be looking for a bright, pale green arc low to the horizon and maybe a few rays poking up through it. The aurora is often though not always more active closer to midnight-1 a.m.

The origin of tonight’s expected aurora is a coronal hole in the Sun’s atmosphere, a magnetic gash that allows protons and electrons to stream away from our star in a fast solar wind. Should those particles slip through Earth’s magnetic defenses, we’ll see aurora tonight. I’ll be watching and hopefully report back with good news unless. Just remember, there’s always the chance we’ll be betrayed like Caesar and have to head home with our heads hanging.

Stephen Hawking, 1980s. NASA

Stephen Hawking died earlier today at his home at age 76. Hawking was a theoretical physicist who suffered from ALS throughout much of his life. Though it increasingly ravaged his body, the disease never touched his mind. He worked on black holes, making the crucial discovery that even the mightiest of them must evaporate over time.

As counter-intuitive as it sounds, what looks like empty space is buzzing with virtual particles, made of both matter and anti-matter, that pop into existence, meet and then annihilate each other in an instant. Particle is a bit of misnomer since they’re really more like fluctuations that suddenly appear and just as quickly fade away.

Hawking showed that near a black hole’s event horizon, the boundary where even light can’t escape its grasp, the hole’s enormous gravity can prevent pairs of particles from combining and annihilating. Instead, one of the pair gets sucked down into the hole and the other is released into space as radiation.

Simulated view of a black hole (center) in front of the Large Magellanic Cloud. Note the gravitational lensing effect, which produces two enlarged but highly distorted views of the Cloud. Across the top, the Milky Way disk appears distorted into an arc. Alain r / CC BY-SA 2.5

Since radiation is energy, the black hole loses energy — called Hawking radiation — over time until it eventually evaporates into nothing. How long does this take? For black holes with the mass of the sun, 1067 years, which is the number “1” followed by 67 zeros. For supermassive black holes like what sits at the center of the Milky Way galaxy, it would take 10100 years. Both are far, far longer than the age of the universe.


This video will help you understand virtual particles and Hawking Radiation better

By coincidence, Hawking passed on Pi Day, named for the Greek letter π. Pi is a constant (a number that doesn’t change) used in math to represent the ratio of the circumference of a circle to its diameter, which is about 3.14159. Pi has been calculated to more than a trillion of digits and goes on infinitely without repeating. Mathematicians define it as both an irrational and transcendental number. Pi was undoubtedly a familiar face in Hawking’s professional life, so it seems appropriate he shares its transcendental nature in death. He also shares his departure date with Albert Einstein’s birthday, who was born on March 14, 1879.

4 Responses

  1. Jeannette

    Honestly, I hoped Stephen Hawking would never die. I gain some comfort that he died on 3/14. Not that I am scientifically adept, it makes sense to me.
    Jeannette

    1. astrobob

      Jeanette,
      It’s fortunate he lived so long given his condition. Those afflicted with ALS often live just a few years.

  2. Hi Bob,

    (I’ve left a comment on your article in Sky and Telescope also). I’m an author with a novel that centres around a character who loves astronomy and I’m looking for some images of Mizar and Alcor. Would you be open to talking with me about your photos? Many thanks,
    Ria Voros

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