Why Einstein Will Never Be Wrong

Einstein Lecturing
Albert Einstein during a lecture in Vienna in 1921. Credit: National Library of Austria/F Schmutzer/Public Domain

One of the benefits of being an astrophysicist is your weekly email from someone who claims to have “proven Einstein wrong”. These either contain no mathematical equations and use phrases such as “it is obvious that..”, or they are page after page of complex equations with dozens of scientific terms used in non-traditional ways. They all get deleted pretty quickly, not because astrophysicists are too indoctrinated in established theories, but because none of them acknowledge how theories get replaced.

For example, in the late 1700s there was a theory of heat known as caloric. The basic idea of caloric was that it was a fluid that existed within materials. This fluid was self-repellant, meaning it would try to spread out as evenly as possible. We couldn’t observe this fluid directly, but the more caloric a material has the greater its temperature.

Ice-calorimeter
Ice-calorimeter from Antoine Lavoisier’s 1789 Elements of Chemistry. (Public Domain)

From this theory you get several predictions that actually work. Since you can’t create or destroy caloric, heat (energy) is conserved. If you put a cold object next to a hot object, the caloric in the hot object will spread out to the cold object until they reach the same temperature.  When air expands, the caloric is spread out more thinly, thus the temperature drops. When air is compressed there is more caloric per volume, and the temperature rises.

We now know there is no “heat fluid” known as caloric. Heat is a property of the motion (kinetic energy) of atoms or molecules in a material. So in physics we’ve dropped the caloric model in terms of kinetic theory. You could say we now know that the caloric model is completely wrong.

Except it isn’t. At least no more wrong than it ever was.

The basic assumption of a “heat fluid” doesn’t match reality, but the model makes predictions that are correct. In fact the caloric model works as well today as it did in the late 1700s. We don’t use it anymore because we have newer models that work better. Kinetic theory makes all the predictions caloric does and more. Kinetic theory even explains how the thermal energy of a material can be approximated as a fluid.

This is a key aspect of scientific theories. If you want to replace a robust scientific theory with a new one, the new theory must be able to do more than the old one. When you replace the old theory you now understand the limits of that theory and how to move beyond it.

In some cases even when an old theory is supplanted we continue to use it. Such an example can be seen in Newton’s law of gravity. When Newton proposed his theory of universal gravity in the 1600s, he described gravity as a force of attraction between all masses. This allowed for the correct prediction of the motion of the planets, the discovery of Neptune, the basic relation between a star’s mass and its temperature, and on and on. Newtonian gravity was and is a robust scientific theory.

Then in the early 1900s Einstein proposed a different model known as general relativity. The basic premise of this theory is that gravity is due to the curvature of space and time by masses.  Even though Einstein’s gravity model is radically different from Newton’s, the mathematics of the theory shows that Newton’s equations are approximate solutions to Einstein’s equations.  Everything Newton’s gravity predicts, Einstein’s does as well. But Einstein also allows us to correctly model black holes, the big bang, the precession of Mercury’s orbit, time dilation, and more, all of which have been experimentally validated.

So Einstein trumps Newton. But Einstein’s theory is much more difficult to work with than Newton’s, so often we just use Newton’s equations to calculate things. For example, the motion of satellites, or exoplanets. If we don’t need the precision of Einstein’s theory, we simply use Newton to get an answer that is “good enough.” We may have proven Newton’s theory “wrong”, but the theory is still as useful and accurate as it ever was.

Unfortunately, many budding Einsteins don’t understand this.

Binary waves from black holes. Image Credit: K. Thorne (Caltech) , T. Carnahan (NASA GSFC)
Binary waves from black holes. Image Credit: K. Thorne (Caltech) , T. Carnahan (NASA GSFC)

To begin with, Einstein’s gravity will never be proven wrong by a theory. It will be proven wrong by experimental evidence showing that the predictions of general relativity don’t work. Einstein’s theory didn’t supplant Newton’s until we had experimental evidence that agreed with Einstein and didn’t agree with Newton. So unless you have experimental evidence that clearly contradicts general relativity, claims of “disproving Einstein” will fall on deaf ears.

The other way to trump Einstein would be to develop a theory that clearly shows how Einstein’s theory is an approximation of your new theory, or how the experimental tests general relativity has passed are also passed by your theory.  Ideally, your new theory will also make new predictions that can be tested in a reasonable way.  If you can do that, and can present your ideas clearly, you will be listened to.  String theory and entropic gravity are examples of models that try to do just that.

But even if someone succeeds in creating a theory better than Einstein’s (and someone almost certainly will), Einstein’s theory will still be as valid as it ever was.  Einstein won’t have been proven wrong, we’ll simply understand the limits of his theory.

Carnival of Space #336

Carnival of Space. Image by Jason Major.
Carnival of Space. Image by Jason Major.

This week’s Carnival of Space is hosted by Joe Latrell at his Photos To Space blog.

Click here to read Carnival of Space #336

And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.

Watch Gaia Go From Lab to Launch in Two Minutes

In the early pre-dawn hours on December 19, 2013, with a rumble and a roar, a Soyuz rocket blazed through the clouds above the jungle-lined coast of French Guiana, ferrying ESA’s long-awaited Gaia spacecraft into orbit and beginning its mission to map the stars of the Milky Way. The fascinating time-lapse video above from ESA shows the Gaia spacecraft inside the clean room unfurling like a flower during its sunshield deployment test, the transfer of the Soyuz from the assembly building to the pad, and then its ultimate fiery liftoff.

That’s a lot going on in two minutes! But once nestled safely in its L2 orbit 1.5 million kilometers out, Gaia will have over five years to complete its work… read more here.

Credit: ESA–S. Corvaja, M. Pedoussaut, 2013. Source: ESA

See the Smallest Full Moon of 2014: It’s the “Return of the Mini-Moon”

Last month's rising "Mini-Moon" of 2013. (Photo by Author)

 Last month, (and last year) we wrote about the visually smallest Full Moon of 2013. Now, in a followup  act, our natural satellite gives  us an even more dramatic lesson in celestial mechanics with an encore performance just one lunation later with the smallest Full Moon of 2014.

We’ve noted the advent of the yearly Mini-Moon, a bizzaro twin to the often over-hyped “SuperMoon,” or Proxigean Full Moon. Occurring approximately six months apart, you can always expect lunar apogee to roughly coincide with the instant of a Full Moon about half a year after it coincides with perigee. In fact, the familiar synodic period that it takes the Moon to return to like phase (such as Full back to Full) of 29.5 days has a lesser known relative known as the anomalistic month, which is the period of time it takes the Moon to return to perigee at 27.55 days.

But the circumstances for “Mini-Moon 2014” are exceptional. The first Full Moon of the year occurs on the night of January 15th at 11:52 PM EST/4:52 Universal Time (on January 16th). This is just 2 hours and 59 minutes after the Moon reaches apogee at 406,536 kilometres distant at 8:53 PM EST/1:53 UT. This isn’t the farthest apogee that occurs in 2014, but it’s close: the Moon is just 32 kilometres more distant on July 28th, 2014. Apogee can vary from 404,000 to 406,700 kilometres, and this month’s apogee falls just 164 kilometres short of the maximum value.

As you can see, this year’s Mini-Moon falls extremely close to apogee… in fact, you have to go all the way back to the Full Moon of November 18th, 1994 to find a closer occurrence, and this year’s won’t be topped until May 13th, 2052! The Moon will appear only 29’ 23” in size on Wednesday night at moonrise, very close to its minimum possible value of 29’ 18”. This is also almost 5 arc minutes smaller than the largest “Super-Moon” possible.

Cool factoid: you actually move closer to the Moon as it rises, until it transits your local meridian and you begin moving away from it, all due to the Earth’s rotation. You can thus gain and lose a maximum of one Earth radii distance from the Moon in the span one night.

We also just passed the most northern Moon of 2014, as it reached a declination of 19 degrees 24’ north this morning at 8:00 UT/3:00 AM EST. This is a far cry from the maximum that can occur, at just over 28 degrees north. This is because we’re headed towards a “shallow year” as the Moon’s motion bottoms out relative to the ecliptic in 2015 and once again begins to widen out in its 18+ year cycle to its maximum in 2024-25.

The position of the Moon Monday night on January 13th in Orion. Credit: Stellarium
The position of the Moon Monday night on January 13th in Orion. Credit: Stellarium

This week’s Moon also visits some interesting celestial targets as well. The waxing gibbous Moon sits just 5.1 degrees south of the open cluster M35 tonight. Notice something odd about the Moon’s position Monday night? That’s because it is passing through Orion the Hunter, one of the six non-zodiacal constellations that it can be found in. Can you name the other five? Hint: one was the “13th sign of the zodiac that created a non-traversy a few years back.

On Tuesday evening, the Moon passes six degrees from the planet Jupiter. This presents a fine time to try and spot the planet in the daytime to the Moon’s upper left, just a few hours prior to sunset.

The Moon will also occult the +3.6 magnitude star Lambda Geminorum on January 15th for observers in northwestern North America. In fact, viewers along a line crossing central British Columbia will witness a spectacular graze along the lunar limb as the star winks out behind lunar mountains and pops into view as it shines through lunar valleys along the edge of the Moon. This can make for an amazing video capture, we’re just throwing that out there…

The occultation footprint for Lambda Geminorum for January 15th. (Created using Occult 4.01 software)
The occultation footprint for Lambda Geminorum for January 15th. (Created using Occult 4.10.11 software)

In addition to being this year’s Mini-Moon, the January Full Moon is also known as the Wolf Moon in the tradition of the Algonquin Native Americans, as January was a time of the mid-winter season when starving wolf packs would howl through the long cold night. The January Full Moon is also sometimes referred to as “The Moon after Yule,” marking the first Full Moon after Christmas.

And just when is the next Super Moon, you might ask? Well, 2014 has three Full Moons occurring within 24 hours of perigee starting on July 15th and finishing up on September 8th. But the most notable is on August 10th, when the Moon passes perigee just 27 minutes from Full. Expect it to be preceded by the usual lunacy that surrounds each annual “Super Moon” as we once again bravely battle the forces of woo and describe just exactly what a perigee Full Moon isn’t capable of. Yes, we still prefer the quixotic term “Proxigean Moon,” but there you go.

Also, be sure to wave a China’s Chang’e-3 lander and rover in the Bay of Rainbows (Sinus Iridum) as you check out this week’s Full Moon, as it just experienced its first lunar sunrise this past week.

Be sure to send those Mini-Moon pics and more in to Universe Today, and let’s get this week’s #MiniMoon trending on Twitter!

LEDs: Light Pollution Solution or Night Sky Nemesis?

New LED lighting along Michigan Street in downtown Duluth, Minn. has brightened and whitened up the area considerably compared to the days of high-pressure sodium lighting. Credit: Bob King

You may have noticed a change underway in your city lighting. High pressure sodium lights, with their familiar orange glow, are quickly being replaced by new, energy efficient  blue-white LED (light emitting diode) lighting. Is this the beginning of a new assault on the night or an opportunity to use light more wisely? Many of us first became aware of LEDs in amplifiers, computers and the flashlights we use for seeing our star charts at night. More recently, LEDs became a big hit with Christmas lighting. And why not? Although they cost considerably more, the bulbs last much longer, use a fraction of the energy compared to incandescent and sodium lighting and don’t contain materials like mercury – common in fluorescent lighting – that can harm the environment. A typical incandescent bulb lasts about 750 hours while an LED bulb can glow for up to 50,000 hours. What’s not to like?

Small individually colored LED lights. LEDs are an electronic light based on semiconductors instead of
Small individually colored LED lights. LEDs light up when an electric current excites electrons inside a semidconductor to produce photons of light. Click to learn more. Credit: Piccolo Namek

The changeover to LED street lighting is already underway in my own city of Duluth, Minn. U.S. I noticed this one night this fall while driving home from work. Buildings and intersections that had been orange the night before were bathed in a far more intense blue-white light. Don’t get me wrong. Our city engineers deserve high marks for adhering to good lighting standards by packaging the new lights in shielded housings with minimal light spill upwards and to the sides. Light in those directions not only creates unwanted glare but seriously brightens the night sky, robbing many of the joys of stargazing.

Comparison of  lighting colors and intensity of the new LED streetlights (left) and the older high-pressure sodium vapor lamps.
Comparison of lighting colors and intensity of the new LED streetlights (left) and the older high-pressure sodium vapor lamps.

Still, everything was not OK. The LED street lights were INTENSELY bright, much more so than the “old-fashioned” sodiums. Looking up was like staring into the sun. If you have the opportunity, step under an orange sodium street light and then under an LED. You’ll be amazed at the difference in light intensity. To gauge the approximate difference in brightness between the two, I pulled out my camera and took a light meter reading on the pavement beneath an LED lamp and then under a high-pressure sodium lamp. The LED was brighter by more than more than one camera “stop” or more than twice as bright.

You can’t complain about the color rendition – the whiter LED light is far better – but the increased intensity doesn’t bode well for stargazers.

Direct comparison of two consecutive light standards - LED in the foreground, high pressure sodium behind it. Credit: Bob King
Direct comparison of two consecutive light standards – LED in the foreground, high pressure sodium behind it. Notice that both lights are well-shielded, ie. no part of the bulb extends beyond its housing. Credit: Bob King

As long as LEDs are shielded, light spill and glare are relatively well-controlled, but light reflected from the ground also goes up into space to light the sky. Here in the northern U.S. where snow typically covers the ground from November through March, winter night skies are the most light polluted; LED street lighting will only exacerbate the situation.

Inexpensive LED wall pack lighting lights a sidewalk and produces large amounts of glare and wasted light. Credit: Bob King
Inexpensive LED wall pack lighting lights a sidewalk and produces large amounts of glare and wasted light. Credit: Bob King

In the big picture however, that’s only a minor headache. LEDs are a wonderful technology, but the benefits they provide in cost savings and long life ultimately guarantee their proliferation in ornamental, building and parking lot illumination. Much of that lighting is unshielded and heavy on glare, making driving at night more difficult, wasting energy and preserving what dark sky remains more challenging. Indeed, the transition is already underway.

Unshielded LED ornamental lighting at a new housing development. Credit: Bob King
Brilliant, unshielded LED ornamental lighting at a new housing development. The full moon is seen at top. Credit: Bob King

Like an outbreak of mushrooms, LED “wall pack” lights – the ones that shine directly outward without any shielding – have started to appear on the outside walls of buildings as a cheap solution for lighting up walkways and parking lots. They’re replacing the equally bad but half as bright sodium lamps. Ornamental LED lamps in a new housing development in town recently turned night into day. Residents complained and wrote letters to the editor. To their credit, the owners dimmed the lights, but the fixtures were poorly designed to start and still too bright for many.

Closeup of LED ornamental light fixtures. Credit: Bob King
Closeup of LED ornamental light fixtures with little shielding. Credit: Bob King

One additional issue with LED ornamental and street lighting has to do with color. Although natural color LED lighting is available, high-efficiency LED lights emit a much bluer light than sodium vapor. Blue-rich light not only increases the amount of glare sensed by the human eye but also the amount of visible light pollution. Other effects of light trespass and glare include sleeping problems and even an increased risk for certain cancers. We humans need the night more than we know.

LEDs are only part of the problem of course. The real issue is the ever-increasing amount of light pollution worldwide and the potential for new LEDs to make it worse. True, we can take advantage of the  ability to adjust and dim current lighting to more suitable levels. LEDs are also highly directional, making it easy to point them just where they’re needed. Finally, new high-efficiency more natural (less blue) LEDs are now available that can help reduce light pollution.

 

First electric lighting: New York City around 1880.
First electric lighting: New York City around 1880.

I encourage everyone to learn all you can about the new lighting and work with you local city councils and town boards to use the light wisely, particularly in new developments, parking lots and for building illumination. There’s no question that LED lighting can be used wisely to make everyone happy – stargazers, drivers, shoppers and walkers. For help and more information, the International Dark-Sky Association (IDA) is a great place to start. Here are some additional resources:

* IDA Simple Guidelines for Lighting Regulations for Small Communities, Urban Neighborhoods and Subdivisions – Great background information on what you’ll need to know before you approach your town board
* Sample Light Ordinances
* Great examples of dark sky compliant ornamental LED light fixtures

What is on the Other Side of a Black Hole?

What is on the Other Side of a Black Hole?

Picture an entire star collapsed down into a gravitational singularity. An object with so much mass, compressed so tightly, that nothing, not even light itself can escape its grasp. It’s no surprise these objects have captured our imagination… and yet, I have a complaint.

The name “black hole” seems to have created something of a misunderstanding. And the images that show the gravitational well of a black hole don’t seem to help either.

From all the correspondence I get, I know many imagine these objects as magnificent portals to some other world or dimension. That they might be gateways which will take you off to adventures with beautiful glistening people in oddly tailored chainmail codpieces and bikinis.

So, if you were to jump into a black hole, where would you come out? What’s on the other side? Where do they take you to? Black holes don’t actually “go” anywhere. There isn’t an actual “hole” involved at all.

They’re massive black orbs in space with an incomprehensible gravitational field. We’re familiar with things that are black in color, like asphalt, or your favorite Cure shirt from the Wish tour that you’ve only ever hand-washed.

Black holes aren’t that sort of black. They’re black because even light, the fastest thing in the Universe, has given up trying to escape their immense gravity.

Let’s aim for a little context. Consider this. Imagine carrying an elephant around on your shoulders. Better yet, imagine wearing an entire elephant, like a suit. Now, let’s get off the couch and go for a walk. This what it would feel like if the gravity on Earth increased by a factor of 50. If we were to increase the force of gravity around your couch up to a level near the weakest possible black hole, it would be billions of times stronger than you would experience stuck under your elephant suit.

And so, if you jumped into a black hole, riding your space dragon, wearing maximus power gauntlets of punchiness and wielding some sort of ridiculous light-based melee weapon, you would then be instantly transformed … by those terrible tidal forces unravelling your body into streams of atoms… and then your mass would be added to the black hole.

Just so we’re clear on this, you don’t go anywhere. You just get added to the black hole.
It’s like wondering about the magical place you go if you jump into a trash compactor.
If you did jump into a black hole, your experience would be one great angular discomfort and then atomic disassembly. Here’s the truly nightmarish part. ..

As time distorts near the event horizon of a black hole, the outside Universe would watch you descend towards it more and more slowly. In theory, from their perspective it would take an infinite amount of time for you to become a part of the black hole. Even photons reflecting off your newly shaped body would be stretched out to the point that you would become redder and redder, and eventually, just fade away.

Artist concept of a view inside a black hole. Credit:  April Hobart, NASA, Chandra X-Ray Observatory
Artist concept of a view inside a black hole. Credit: April Hobart, NASA, Chandra X-Ray Observatory

Now that that is over with. Let’s clear up the matter of that diagram. Consider that image of a black hole’s gravity well. Anything with mass distorts space-time. The more mass you have, the more of a distortion you make….And black holes make bigger distortions than anything else in the Universe.

Light follows a straight line through space-time, even when space-time has been distorted into the maw of a black hole. When you get inside the black hole’s event horizon, all paths lead directly to the singularity, even if you’re a photon of light, moving directly away from it. It sounds just awful. The best news is that, from your perspective, it’s a quick and painful death for you and your space dragon.

So, if you had any plans to travel into a black hole, I urge you to reconsider. This isn’t a way to quickly travel to another spot in the Universe, or transcend to a higher form of consciousness. There’s nothing on the other side. Just disassembly and death.
If you’re looking for an escape to another dimension, might I suggest a good book instead?

Here’s an article I did about how to maximize your time while falling into a black hole.

Astrophotos: Venus at Inferior Conjunction

Venus, 0.4% illuminated and 5.1 degrees from the Sun, as seen about 12:30 pm local noon time from Sri Damansara, Malaysia (0430 UTC) on January 11, 2014, about about 8 hours before inferior conjunction. Credit and copyright: Shahrin Ahmad.

Venus has now gone from being that bright “star” you’ve been seeing around sunset to later this month being the bright object you’ll see in the early morning pre-dawn hours. On January 11, Venus passed between Earth and the Sun in what is known as inferior conjunction. We challenged our readers to try and capture it, and Shahrin Ahmad in Malaysia nabbed the tiny crescent Venus about 8 hours before inferior conjunction, in what he said was a personal record!

“Around 12.30 p.m. local noon time, there was a brief of good seeing, and probably the best one so far,” Shah said via email. “Suits nicely as a parting shot. After that the sky seeing began to deteriorate really fast!”

Venus was about 0.4% illuminated and 5.1 deg from the Sun.

“Even without stretching the original photo, we can easily see how the crescent has reach beyond 180 degrees around Venus,” he said. “This is the closest Venus I’ve ever imaged.”

You can see Shah (and his telescope) on the Virtual Star Party this week, talking about his Venus observations.

But take a look at this: here’s a great series of images from Paul Stewart from Timaru, New Zealand:

Venus inferior conjunction timeline from January 7 to 13th, missing January 12 due to clouds. Credit and copyright: Paul Stewart.
Venus inferior conjunction timeline from January 7 to 13th, missing January 12 due to clouds. Credit and copyright: Paul Stewart.

Wow! That’s exceptional work! You can see more of Paul’s astro-work at his website, Upside Down Astronomer.

Thanks to both Shah and Paul for sharing their photos!

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

A Distant View of Janus, One of Saturn’s ‘Dancing Moons’

Cassini narrow-angle camera image of Janus from Sept. 10, 2013 (NASA/JPL-Caltech/SSI)

One of 62 moons discovered thus far orbiting giant Saturn, Janus is a 111-mile (179-km) -wide pockmarked potato composed of rock and ice rubble. The image above shows Janus as seen with Cassini’s narrow-angle camera on September 10, 2013, from a distance of 621,000 miles (1 million km), floating against the blackness of space.

Despite its apparent isolation in the image above, though, Janus isn’t alone. It shares its orbit around Saturn with its slightly smaller sister moon Epimetheus, and they regularly catch up to each other — and even switch places.

Janus and Epimetheus: Saturn's "dancing moons" (NASA/JPL/SSI)
Janus and Epimetheus: Saturn’s “dancing moons” (NASA/JPL/SSI)

Janus and Epimetheus travel in nearly the same track, about 94,100 miles (151,500 km) out from Saturn. They occasionally pass each other, their gravity causing them to switch speeds and positions as they do; Janus goes faster and higher one time, slower and lower the next – but the two never come within more than about 6,200 miles of each other.

The two moons switch positions roughly every four years.

This scenario is referred to in astrophysics as a 1:1 resonance. Astronomers were initially confused when the moons were discovered in 1966 as it wasn’t known at the time that there were actually two separate moons in a single orbit. (This wasn’t confirmed until Voyager 1’s visit to Saturn in 1980.) It’s been suggested that Janus and Epimetheus will eventually come to orbit a single Lagrangian point around Saturn instead of trading places… in about another 20 million years.

The view above looks toward the Saturn-facing side of Janus. Covered in both dark and light colored material, Janus’ surface is thought to be coated with a layer of fine dust that slides down its steeper slopes, revealing the brighter ice beneath.

Cassini image of Janus from April 2010 (NASA/JPL-Caltech/SSI)
Cassini image of Janus from April 2010 (NASA/JPL-Caltech/SSI)

Want to see more images of Janus? Click here.

Source: Cassini Solstice Mission release