Dark Energy Bad for Planets

(Disclaimer: This writer took Honours Physics from Dr. Marcy and received an A. Otherwise she is not involved in any of the missions mentioned, except for knowing the principals and the story.)

Happy D-Day June 6!

Dr. Geoffrey Marcy, along with colleague Paul Butler, were first to discover planets orbiting other stars. (However, another group in Europe beat them to the publishing line.) Since 1995 Dr. Marcy has become the leading planet hunter, discovering hundreds of new worlds. May 27 at a symposium in MIT, Dr. Marcy expressed his anger that a Terrestrial Planet Finder mission, which he has long advocated, has been pushed out of the funding queue. TPF was conceived to examine the nearest stars for habitable planets. Dr. Marcy lamented that planet hunting does not have support in the astrophysics community. In a 2001 Decadal survey, TPF was a number one priority. Since then many of NASA's astrophysics missions have been cancelled, largely due to emphasis on "dark energy."

In the 2006 NASA budget, TPF was delayed indefinitely. The troubles continued in 2007, when an ad hoc committee of the National Research Council pushed a Joint Dark Energy Mission (JDEM) to the front of the astrophysics line. In Newport Beach this writer argued to the committee that "dark energy" would be bad for science. In the 2010 Decadal Survey, a cobbled-together concept called WFIRST, based on JDEM, was given first priority. Now, due to the mounting costs of the James Webb Space Telescope, WFIRST or anything like it are not likely to fly until year 2030.

How many times does a Cassandra have to warn that "dark energy" is a bad idea? While press stories crow about DE, other promising science has been pushed aside. TPF has also faced competition from a Space Interferometry Mission. Among the wreckage is an International X-Ray Observatory (IXO) and the LISA mission to search for gravitational waves, also delayed indefinitely. The end result is that no missions, even "dark energy" missions, will fly anytime soon.

Discovery of new worlds is a great achievement for science. Humans have long dreamed about exploring planets in other solar systems. Dr. Marcy, the Kepler mission, and others have shown that extrasolar planets are many and varied. The bottom line is that untold numbers of planets exist, while "dark energy" probably does not. Why should emphasis on DE be allowed to wreck science?

Planets Going Backwards

Tranisiting exoplanets are found by the light curve they create when passing in front of their parent star. Many of these planets are "hot Jupiters" orbiting very close to stars. Discovery of nine new transiting exoplanets was announced this week. When these results were combined with earlier discoveries, it was found that 6 of 27 exoplanets were orbiting in the opposite direction from the star's rotation. This challenges theories of stellar formation.

Since Pierre Laplace, scientists have thought that solar systems condense from rotating disks of gas. As a result, the planets should orbit the same direction as the star rotates, as in our solar system. Unfortunately nature does not follow the theory. The very existence of "hot Jupiters" challenges the old theory. Orbiting so close to their parent star, these planets should boil away. The theory can not explain how planetary embryos can form from dust. If particles collide at orbital velocity they will ricochet rather than stick together.

If these planets formed around Black Holes, they would follow the Black Hole's rotation independently of the parent star. The Black Hole would not suck these planets up, but would stabilize their centres. As a result Jupiter-size planets could exist very close to Suns, as observed. Black Holes could exist within most planets, even Earth. Planets orbiting in the opposite direction from their stars are another sign of Black Holes where no one has thought to look.

Your Planet Shouldn't Exist

This terrarium is at the new California Academy of Sciences in San Francisco. By ascending a series of passageways one passes through all levels of a rainforest, from underwater to above the treetops. Hopefully we will build such domes on the Moon someday.

San Francisco State University is often overlooked in favour of those other colleges across the Bay. At SFSU Geoffrey Marcy and Paul Butler became the first extrasolar planet hunters. At first no one believed their findings, and they had difficulty getting published. Today science recognises hundreds of planets in other solar systems. Dr. Debra Fischer continues the planet hunt at SFSU today. (Disclaimer: Dr. Marcy also taught in Berkeley, and gave the writer an A in Honours Physics.)

From the time of Pierre Laplace, scientists have thought that planets coalesce from rotating disks of gas surrounding stars. New computer simulations by Joseph Barranco of San Francisco State University call this old theory into question. Using hundreds of parallel processors, Barranco made the first 3D simulations of planet formation. These more complex simulations introduced turbulence from Coriolis forces and vertical shearing. Because of these forces, early planets would have been torn apart. According to the simulation, our planet should not exist.

The old theory of planet formation has long suffered flaws. If particles collide at orbital speeds, they would ricochet rather than stick together. Small particles would need the masses of mountains to form planets. Planet hunters have also found many “hot Jupiters,” giant planets orbiting very close to stars. Under the old theory, such worlds should not form. Heat from the star would boil their surfaces and tidal forces would tear them apart. The old theory of planet formation needs something else to work.

The Big Bang may have created many billions of tiny Black Holes. They would have formed from quantum fluctuations grown large by expansion of the Universe. A primordial Black Hole would have the mass of a mountain, yet be smaller than an atom. Quietly orbiting in Space, they would be very difficult to detect. Tiny holes could be ubiquitous, even within our solar neighbourhood.

When our solar system was nothing but a cloud of gas, small Black Holes would have drawn the gas into their influence. The Black Holes were too tiny to suck everything up, but the tiny amount they did eat made the rest grow hot. Eventually a Black Hole would be surrounded by rock with a hot center. This was the birth of the planets.

If our Earth contained a tiny Black Hole, outward radiation pressure would prevent us from being eaten. Earth’s centre would be a whirlpool of charged particles surrounding the Black Hole. Radiation from the core would reach the surface as volcanic heat. If the Black Hole rotated, it would generate a magnetic field whose axis would not necessarily be parallel with Earth’s spin axis. Our planet behaves exactly as if it contained a Black Hole.

First Photos of Exoplanets

Astronomers may have taken the first direct images of planets orbiting other stars. The infrared photo above was taken by our Gemini North telescope atop Mauna Kea. A trio of planets are shown orbiting star HR 8799. The 2006 Hubble Space Telescope image below shows a ring of debris orbiting Fomalhaut. The planet (inset) has a mass about 3 times that of Jupiter and would orbit the star every 872 years. As we have seen with Saturn's moons, this planet would sculpt the ring edges.

One Hot Planet

Astonomers have now discovered many "hot Jupiters," gas giants orbiting very close to their sun. On May 9, 2007 Hot Gas reported object HC 149206b orbiting its star in 2.877 days with a surface temperature of 2040 degrees Celsius. On August 7, 2007 Milkshake Planets reported that TrES-4 has 1/3 the density of liquid water but a surface temperature of 2300 degrees!

This week the UK Wide Area Search for Planets has found WASP 12-b by occultation of a star 800 light-years away. The planet is 50 percent more massive than Jupiter, and orbits in only 1.1 days! The temperature of WASP 12-b is calculated to be 2250 degrees Celsius. How such worlds can exist without boiling away is a challenge to theories of planet formation.

If giant planets formed around singularities, presence of the Black Hole would stabilise their structure and prevent them from evaporating. Since the time of Laplace, astronomers have theorised that planets somehow condensed from rotating clouds of gas. In such a nebula, tiny Black Holes would have seeded planetary formation. In the case of Jupiter, an internal singularity would explain both internal heat and magnetic field. The interiors of gas giants are excellent places to seek Black Holes.

Sighting a New World

Using our Gemini North telescope atop Mauna Kea, astronomers may have the first photograph of a planet orbiting a sunlike star. Star 1RXS J160929.1-210524 is 500 light-years from Earth. The planet has about 8 times the mass of Jupiter and an orbit approximately 330 astronomical units in diameter. Current models of planet formation can not explain a giant planet orbiting so far from its primary. The gaseous disk that is thought to precede solar system formation would be thin indeed.

If this planetary object formed around a primordial Black Hole, the singularity would gather mass even from a thinnest disk. The Black Hole would be too small to ignite the fusion of a sun, but large enough to produce a Jupiter-like object. This planet's estimated temperature is around 1500 degrees C, possibly indicating an internal source of heat.

Last week's operation of the LHC led to some silly fears about Black Holes. Even if a Black Hole existed inside Earth, we would not be sucked up. Outward radiation pressure would balance gravity's inward pull until an equilibrium was achieved. Presence of a Black Hole would cause Earth to have internal heat and a magnetic field whose poles do not coincide with the geographic poles. Makes one think, does it not?

Milkshake Planets

This Cassini photo of Saturn was taken July 8, 2007 from a distance of 2.9 million kilometers. Both circular and linear cloud features are visible. Each pixel represents an area 17 kilometers across. Saturn is the planet with the lowest density in our Solar System, barely 0.7 g/cc or the density of a milkshake. In a giant tub of water the planet would easily float.

Lowell and Palomar Observatories have jointly discovered the largest known planet yet found, orbiting a star 1400 light-years away. The new world, called TrES-4, has a diameter 1.7 times that of Jupiter. Its density is half that of Saturn, or 1/3 the density of liquid water! The temperature of TrES-4 is estimated at 2300 degrees Celsius, so hot that the surface should boil off. Scientists are at a loss to explain how such a world can exist.

It is not widely mentioned in astronomy textbooks that scientists can't explain how ANY planets formed. The standard explanation is that planets condensed from gas clouds, but tiny particles colliding at orbital velocities simply will not stick together. Particles would need the mass of mountains to attract matter. Recently many "hot Jupiters" have been discovered orbiting so close to their stars that they should boil away.

The Big Bang created billions of tiny singularities, many with the mass of mountains. The solar system was probably started when some of these tiny Black Holes collided with gas clouds. If planets formed in this manner, presence of the Black Hole would hold the gas together and prevent it from boiling off. The Black Hole's gravity would allow the planet to have an extremely low density.

Writing this makes one very hungry. It will take a long time for all this to be accepted, but that is time to enjoy plenty of milkshakes!

The Icy River Styx

Pluto and its moon Charon imaged by the Hubble Space Telescope. An article in this week’s Astrophysical Journal reports that water issues from Charon’s interior into Space. Our Gemini North Telescope atop Mauna Kea found spectra of ammonia hydrates and water. These spectra point to cryovulcanism within Charon. Liquid water exists inside this distant moon and is escaping into Space.

Pluto was king of the underworld, and Charon was the ferryman carrying souls across the River Styx. At one time Pluto was considered the outermost planet. Now we know that Pluto and Charon mark the beginning of a Kuiper Belt containing hundreds of objects. Some of these objects are bigger than Pluto itself, causing its demotion to a minor planet. Other Kuiper Belt objects could also contain liquid water.

Previously the Cassini spacecraft observed water erupting from the Saturn’s moon Enceladus. The explanation for Enceladus has been tidal forces, even though that moon is too distant from Saturn for tides to be a factor. In the case of Charon, the old idea of “radioactive decay” has been exhumed. As far as is known there are almost no radioactive elements in the outer Solar System.

The Big Bang created billions of tiny Black Holes. They could have formed the seeds of clusters, galaxies and even smaller objects. When our solar system was just a cloud of gas, these tiny Black Holes seeded the planets and even some moons. These singularities are too tiny to swallow everything up, but they generate heat to warm planetary interiors.

Liquid water within Charon is direct evidence of internal heat. The most likely heat source for Charon, Enceladus and outer solar system bodies is a tiny Black Hole. Heat from these objects could support life, even in interstellar Space. Kuiper Belt objects and even brown dwarfs are potential homes of extraterrestrial life.

The new Carnival of Space is out with posts about the Solar System and beyond!

Brown Dwarf Is Cool

By now everyone has heard the controversy whether Pluto is a planet. At the other end of the planetary mass scale another controversy is brewing, the boundary between large planets and brown dwarves. The latter are objects between 10-80 Jupiter masses, not big enough for the nuclear reactions of a star but still giving off heat through some mysterious process. Just last month a brown dwarf pulsar was discovered giving off beams of radiation.

Until recently the very existence of brown dwarfs was just a theory. Thanks to infra-red telescopes, we now have discovered many. Yesterday astronomers from the UK Infrared Telescope and Gemini South observatory announced discovery of ULAS J0034-00, the coolest solitary brown dwarf yet found. Its surface temperature is only about 650 degrees, and its mass is between 15-30 times that of Jupiter. It is located approximately 50 light-years away in the constellation Cetus, alone in Space without a parent star. There may be many other similiar objects out there.

Also at the American Astronomical Society meeting in Honolulu, another group of astronomers announced discovery of exoplanet XO-3b. Until a few years ago the existence of extra-solar planets was doubted, like a changing speed of light. With a faith born in science fiction, astronomers today have found hundreds. Having a mass of 13 Jupiters, X0-3b occupies a boundary between big planets and brown dwarfs. It orbits its star in less than 4 days, the largest object yet found in so close an orbit.

It was thought that an object so close to a star would have a circular orbit, otherwise tidal forces would tear it to bits. Not knowing this, X0-3b has taken a highly elliptical orbit. Something else holds this object and other "hot Jupiters" together. Presence of a central Black Hole would explain why Jupiter gives off twice as much radiation as it receives from the Sun, and why brown dwarfs give off heat.

We must also thank the wondrous Kea for pointing out discovery of TWO planets around metal-poor star HD 155358. Once it was thought that heavy metals are necessary for the cores of planets to accrete. HD 155358 formed so long ago (10 billion years!) that it has almost no metals. As we have now discovered many extrasolar planets, new theories are needed.

Yet another group of astronomers today announced discovery of TrES-3. This transitting planet orbits a star in the constellation Hercules with a period of only 31 hours! It surface temperature is about 1500 degrees Kelvin. Old theories can not explain why this planet doesn't boil away. If planets and dwarfs formed around singularities, that would explain how they stay together.

Just as the line between Pluto and planets has become blurred, the boundary between big planets and small stars is being eaten away. It is better to think of a continuous mass scale from minor planets to gas giants, small stars and beyond. The same processes govern the formation of all these objects. If you want to find a nearby Black Hole, look beneath your feet.

Check out the new Carnival of Space!

Echoes From the Darkness

Two discoveries announced in the past day, seemingly from different scales and regions of the Universe, may be related. The Hubble Space Telescope has found that Galaxy Cluster Cl 0024+17 is surrounded by a halo of dark mass. (This is distinct from "dark energy," which doesn't exist.) This cluster, 5 billion light-years away, apparently formed from a collision of two clusters about 1 billion years before this picture was taken or 6 billion years ago. The impact formed an expanding ring of dark mass which can be detected through gravitational lensing. Though mounting evidence exists, the nature of "dark matter" is still just a subject of speculation.

Just last week we learned of a hot gas giant orbiting inexplicably close to its star. Again using stellar occultation, astronomers have discovered that planet TrES-3 orbits its sun in only 31 hours! It's orbit takes the planet barely 3 million km from a sun. Current theories can not explain these hot Jupiters. In the immense heat near a star almost anything would boil away before forming a planet.

The Big Bang created billions of Black Holes in a variety of sizes. The biggest ones formed the seeds of galaxies and clusters. Smaller singularities formed great haloes around the galaxies, as seen near Cl 0024+17. Many times these objects have collided with a galaxy's disk. They could have formed the seeds of stars and even smaller objects like planets. Presence of a singularity inside "hot Jupiters" would explain their formation and number.

There is new evidence of disk of dark mass deep within our solar system, something I will write about sometime. There is far more out there than meets the eye.

New World

Astronomers at the European Southern Observatory have discovered an "Earthlike" planet orbiting star Gliese 581, only 20.5 light-years away. This planet (foreground) has mass 5 times that of Earth and orbits the star every 13 Earth-days. Because Gliese 581 is a dim red dwarf, this leads to conditions favourable to life. The planet's mean temperature is between 0 and 40 degrees Celsius, suitable for liquid water.

Our own planet occupies a very narrow habitable zone, where the porridge is neither too hot nor too cold. As we have seen before, Earth's temperature has remained comfortable because light has been slowing according to GM=tc^3. The same equation that keeps our Sun relatively stable applies to Gliese 581 and any other star. If c did not slow, the habitable zone would expand to pass Earth by. Life would have difficulty evolving on any planet anywhere.

The High Altitude Radial Velocity Planet Searcher (HARPS) mounted on the 3.6 meter telescope has discovered many planets. Around Gliese 581 it has also discovered a Neptune-sized planet, pictured in blue, orbiting the star every 5 days. In the distance another planet orbits in 84 days. The painting is very pretty; one can easily imagine some future starship enjoying this same view.

We can only imagine what sort of life would evolve here. This planet's gravity would be about 2.2 times that of Earth, so they might be more solidly built. Since the star's light is redder than ours, their eyes would be sensitive to longer wavelengths, as a snake can see in infrared. Our red would be white to them.

(ESO, are you there? I appreciate the notices but the lighting is all wrong. The "Earthlike" planet seems to be lit from a yellow Sun-like star somewhere off to the right. The blue Neptune-like planet seems to be lit from a different source entirely. Many science fiction movies make similiar mistakes. I can happlily correct this painting for you. )