Einstein's Lens Splits Space and Time

This year, we celebrate the 100th anniversary of the first publication of Einstein's greatest masterpiece, the General Theory of Relativity.  Now astronomers using the Hubble Space Telescope have found a remarkable quadruple image of a distant exploding star which helps confirm another of that theory's most "far out" predictions.

The General Theory connects space, time, and gravity in mind-boggling ways.  Strong gravity can actually warp (or bend) space and distort the flow of time.  One example of gravity strong enough to do this is a dense cluster of galaxies, like the one shown on our image.  Everything on this Hubble picture that is not a point of light (everything with a shape) is a galaxy of billions of stars.  The cluster contains many such galaxies orbiting a common center. 

Light from more distant objects behind the cluster has to go through the strong gravity of the cluster on its way to us.  Einstein's theory predicts that as gravity warps space, the light from behind the cluster will have to travel through that warped space and will get twisted and bent in eerie ways.  From the right angle, a single beam of light can be split into four similar images, something called an "Einstein Cross."  That's just what you see in the inset on the picture.

Most amazingly, the four images of the exploding star took slightly different amounts of time to get to us through that warped space, and so we are seeing the same explosion at four different time periods.  By studying the details of such complex "gravitational lenses" (as the distortion by the galaxy cluster is called), astronomers hope to learn more about how all the "stuff" in those galaxies is distributed and how much of it is regular matter and how much is dark matter.

The galaxy cluster only has a catalog number, not a name, but we know it is about 5 billion lightyears away (meaning light, traveling at the fastest permitted speed in the universe, took five billion years to reach us.)  The exploding star appears to be four billion lightyears further than that -- meaning we are seeing its light from 9 billion years ago.  The only reason we can see it at all is that the gravity of the galaxy cluster actually intensifies the light as well as splitting it -- just as Einstein's theory predicts.  

What a wonderful image with which to celebrate the 100th anniversary of a theory that Einstein's called "the happiest thought of my life!"

(Click on the image to see it bigger -- believe me, it's worth it!)

Coming Up: Pi Day, Einstein’s Birthday, and Dawn at Ceres

Saturday, March 14, 2015 is “pi day” – the only day this century that includes the first five digits of pi or 3.1415…   This year, several groups are suggesting that this might be a good day for celebrating math and science in general – and raising our voices in favor of evidence-based, well-reasoned decisions in our public life.  It’s a time we can share with others our conviction that evolution is well-established fact, that climate change is being accelerated by human activities, and that NASA did indeed land people on the Moon – all ideas being denied on the web, in the media, and in our political discourse.

March 14^th is also Albert Einstein’s birthday (he was born in 1879 on that day.)  This year, we celebrate the 100^th anniversary of Einstein’s first paper on the General Theory of Relativity, the brilliant insight that connects gravity, light, space and time.  This anniversary is part of a larger physics commemoration – celebrating 2015 as the International Year of Light.  At Foothill College, I will be offering my evening Physics 12 class (Physics for Poets), all about Einstein’s life and work, explained without math.  It ends with recent contributions to our understanding of the universe by Stephen Hawking (whom I was pleased to see getting the Academy Award for best actor :-)) 

We can also celebrate the big development in the solar system: The Dawn Spacecraft just went into orbit around the largest asteroid in the asteroid belt, Ceres, which, by virtue of its size and round-ness, also qualifies as the first dwarf planet to have been discovered (in 1801).  Dawn is the first spacecraft ever to orbit two worlds on the same mission, thanks to its advanced ion-propulsion technology.  (It orbited the second largest asteroid Vesta, from 2011 to 2012 and then made its way across 900 million miles of space to Ceres.)  We are expecting remarkable close-up images of and data from Ceres as the year goes on and Dawn achieves closer and closer orbit. Stay tuned.

For the latest on the Dawn mission, see the blog by Mission Director Marc Rayman: http://dawnblog.jpl.nasa.gov/ 

For a syllabus of my Physics 12 (Einstein) class, see: www.foothill.edu/physics/Physics.12.Web.pdf

For a guide to resources for answering conspiracy-theory "true believers", go to: http://www.astrosociety.org/education/astronomy-resource-guides/astronomical-pseudo-science-a-skeptics-resource-list/ 

Painting of the Dawn Spacecraft Near Ceres (NASA)

HBO is Showing "Einstein and Eddington" Now

In 2008, the BBC made a biopic (or dramatization) of events in Albert Einstein's and Arthur Eddington's life and work, and how they intersected. It was cosponsored by HBO and I just found out that HBO is currently showing this film (you can see it in the "On Demand" section of your cable TV offerings if you subscribe to HBO.) It may not last long, and it is not available on DVD yet in the U.S.

I recommend it with some enthusiasm (it's moving, and fun to watch), but also many reservations (the science and history are not always accurate, or -- to be charitable -- are twisted or changed in the interests of higher drama.)

I think everyone has heard of Einstein, but Arthur Eddington was an astronomer and physicist in England in the early part of the 20th century who contributed a lot to our understanding of how stars work. He was also a key member of the eclipse expedition in 1919 that tested if Einstein's crazy new theory of gravity, space, and time -- the general theory of relativity -- was correct. Measurements during that eclipse, and especially during a later eclipse made by a team from the Lick Observatory, established that Einstein was right and that the universe was more complex and beautiful in its inner workings than earlier scientists had imagined.

The film begins and ends around the eclipse expedition, but then goes back in time to set the scene. Many historical details are wrong or skipped over -- Elsa was divorced with two kids when she re-encountered Einstein in Berlin, the famous image of Einstein sticking out his tongue was later in his life, Eddington didn't have to tell Einstein about Mercury, etc. But such details don't matter to most viewers, and sometimes mixing things up a bit helps move the story along. And the flavor of the excitement around relativity is well characterized, with the two main actors doing a nice job in portraying the scientists and their personalities.

If you get HBO, or have a friend who does, and have a chance to see it, I recommend the film for everyone except historians of 20th century science, who will have a fit about those details. (The same production team also did a biopic about Stephen Hawking, called just "Hawking" and I gather you can find that film in segments on YouTube.)

Above you see the two scientists as portrayed in the movie, below you see the two of them from real life.
(For movie and TV fans, I can't resist adding: Gollum plays Einstein, Dr. Who plays Eddington.)

Happy Belated Einstein's Birthday (Get Ready for Spring)

Yesterday was Albert Einstein's birthday and this coming Thursday will be the Spring Equinox, when the length of the day and the length of the night are roughly equal, and we move from winter to spring in the Earth's northern hemisphere. This is always a good time of year to think fresh thoughts, something Einstein was especially good at.

At Foothill College, where I have the privilege of teaching, this is the week we begin registering students and community members for our spring quarter, which starts in April. This spring, I get to teach my evening Physics 12 class, nicknamed "Everything You've Wanted to Know about Einstein and his Work (without Math) but Were Afraid to Ask..."

If you, or someone you know, might be interested and are close enough to Los Altos, California to come to an evening class, I invite you to check it out.

Although Einstein died in 1955, his work continues to capture the imagination of both scientists and the public. In the last few years, astronomers have found new confirmation of some of Einstein’s most bizarre ideas -- including time itself slowing down under the right circumstances and gravity acting like the distorting mirrors of an amusement park. Huge black holes have been found, some of them having “eaten” enough material to make billions of Suns.

In the Physics 12 course, we explain all these ideas and discoveries in everyday language -- using analogies, visuals, and humor instead of math. Physics 12 will be offered on Tuesday and Thursday evenings from 6 to 8:30 pm, April 8 to June 24, 2014. Pre-registration is advised, but, if there is room, you can come hear the first lecture (room 5015) and then register if you like the approach. The class is held on the main campus of Foothill College in Los Altos Hills, just off Freeway 280. (For adults who don't need a grade, arrangements can be made, after you register, to take the course without the exams.)

For registration information for the Spring Quarter see:
http://www.foothill.edu/admissions.php

Physics 12 emphasizes key ideas that form the basis of our modern concepts of space, time, matter, and energy:
* The theory of how atoms work
* Energy, heat, and the arrow of time
* The special theory of relativity: what happens when you travel close to the speed of light
* The general theory of relativity: gravity, space-time warps, and black holes
* Quantum mechanics: the bizarre rules that govern the world inside the atom

In addition to examining the physics and physicists involved with these areas, the course also takes a brief look at the effects that such physics ideas have had on the humanities -- including poetry, fiction, music, and the public view of scientists. The quarter concludes the course with a non-technical introduction to the work of Stephen Hawking, whose innovative ideas combine these areas and take some of Einstein's ideas to the outermost limits of cosmic possibility.

For a course syllabus in pdf format, see:www.foothill.edu/physics/Physics.12.Web.pdf

A Triple System of Star Corpses

An international team of astronomers has just reported the discovery of one of the weirdest star systems we have ever seen -- a triple system of star corpses (dead stars) whirling around each other in a space smaller than the Earth's orbit around the Sun.

The system of stars is more than 4,000 light years away, in the constellation of Taurus. (But this story is no bull!) The system doesn't have a name, only a catalog number.  It consists of one "neutron star" (which pulses with radio waves) and two "white dwarfs."  Generally, a tiny "neutron star" only forms after a massive star dies by blowing itself to pieces, leaving a very compressed remnant (or "corpse") behind.  So, those three stars, which show evidence of having formed together, had to remain together even when the biggest star of the three exploded.  Later, the two smaller stars died and also became compressed objects (not much bigger than a planet) called "white dwarfs."  (They get that name because they are small and white hot.)

Now the three corpses continue to spiral around each other, in a strange cosmic ballet .  The heaviest corpse, the "neutron star" is really dense -- it is so compressed that to make something like it on Earth, we would have to take all the people in the world and squeeze them into a raindrop!  (Then we would have one rain-drop sized piece of the neutron star.)

Sometimes we see such "neutron stars" giving off spinning magnetic beams of radio waves.  Whenever such a radio beam sweeps over the Earth, we get a pulse of radio waves.  In such cases, we also call these dead stars "pulsars."   Their beams of energy can be timed with great accuracy.

In 1974, my former college advisor, Joseph Taylor (and Russell Hulse,) discovered the first pulsar in a double star system.  Measuring its pulses enabled them to verify important predictions of Einstein's General Theory of Relativity, and earned them the 1993 Nobel Prize in Physics.  At the time, astronomers thought that finding a neutron star/pulsar with a companion was pretty surprising (although today other double systems are known.)

Now suddenly, we have a neutron star/pulsar with TWO companions.  How completely and wonderfully weird!  And this particular neutron star spins hundreds of times per second. Its fast spin and two companions will allow astronomers to measure the predictions of Einstein's theories even more precisely than we have been able to do in the past.

Star Corpses Help Us Prove Einstein Right

One of the most intriguing predictions of Einstein's theory of relativity is that, just like there are light waves and sound waves, there should also be GRAVITY WAVES. When the arrangements of massive objects in the universe changes (like two stars orbiting each other), Einstein's theory predicts that waves of gravity energy should be be given off.

But gravity waves are very, very weak and hard to detect. We have gravity wave telescopes operating, but so far they have not succeeded in catching some big gravity change that would give off enough waves to be measurable. So astronomers are turning the idea around. If we could find two massive stars in the universe that are in orbit, they should be giving off these subtle gravity waves and should be losing energy. That means the two stars will -- as their motion energy is lost -- spiral inward toward each other, something they would not normally do. The more compressed the star, the bigger the effect. Dead stars, that have fallen inward -- gotten "squozen" in death (as I like to say) are excellent subjects for testing this prediction.

Two astronomers in the mid-1970's, including one of my undergraduate advisors, Dr. Joseph Taylor, discovered two star corpses (collapsed stars) that showed exactly this kind of behavior. There were the two dead stars, called neutron stars, minding their own business in space, lost in each other's gravity embrace. Yet, they were very slowly approaching each other in orbit. And the energy they lost was exactly what Einstein predicted. Taylor and Russell Hulse won the 1993 Nobel Prize in physics for their painstaking observations of this pair. But their measurements were done with radio waves, since that was the only way to see these particular star corpses.  

(For those of you who know a little astronomy, the precise story is that most neutron stars are only observable as "pulsars" -- objects that give off regularly pulsing radio waves.  As the two pulsars orbit, they lose energy and their pulses change as they get closer to each other.)

Now, a larger team of astronomers has just announced finding a different pair of dead stars (called white dwarfs) that show the same spiraling behavior, but shining in visible light. The nameless pair of star corpses is about 3,000 lightyears away. As they orbit close around each other (taking only 13 minutes for an orbit!), we see one eclipse the other. Between April 2011 and today, the eclipses have come 6 seconds earlier, as the two dead stars lose energy and approach. This is, again, exactly what we would expect if Einstein is right, and the pair is losing energy via gravity waves.

(Just as a lightbulb loses energy as it shines away light, and you have to pay the electric company to replace it, so it seems orbiting stars slowly lose energy as gravity waves. The difference is that there is no source of new energy, and so the stars simply fall slowly toward each other.)

How nice that Einstein's ideas, now almost 100 years old, are being confirmed in some of the strangest astronomical environments we can find. He'd be proud.