ARTIFICIAL PLANET

Astronomers Radically are Building the Planets:

Observations of faraway worlds have forced a near-total rewrite of the story of our solar system. Planets in a row .

Newborn star systems imaged by the ALMA telescope, featuring protoplanetary disks with rings, arcs, filaments and spirals, are among the observations changing the theory of how planets are made illustrations

First, Mercury: More charred innards than fully fledged planet, it probably lost its outer layers in a traumatic collision long ago may be (100 yrs ). Next comes Venus and Earth, twins in some respects, though oddly only one is fertile (having life). Then there’s Mars, another wee world, one that, unlike Mercury, never lost layers; it just stopped growing. Following Mars, we have a wide ring of leftover rocks, and then things shift. Suddenly there is Jupiter, so big it’s practically a half-baked sun, containing the vast majority of the material left over from our star’s creation. Past that are three more enormous worlds—Saturn, Uranus, and Neptune—forged of gas and ice. The four gas giants have almost nothing in common with the four rocky planets, despite forming at roughly the same time, from the same stuff, around the same star. The solar system’s eight planets present a puzzle: Why these?

Original story reprinted with permission from Quanta Magazine, an editorially independent publication of the Simons Foundation whose mission is to enhance public understanding of science by covering research developments and trends in mathematics and the physical and life sciences.

Now looking out past the sun, way beyond. Most of the stars harbour planets of their own. Astronomers have spotted thousands of these distant star-and-planet systems. But strangely, they have so far found none that remotely resemble ours. So the puzzle has grown harder: Why these, and why those?

Astronomer Explains How NASA Detects Asteroids:

The swelling catalog of extra solar planets, along with observations of distant, dusty planet nurseries and even new data from our own solar system, no longer matches classic theories about how planets are made. Planetary scientists, forced to abandon decades-old models, now realize there may not be a grand unified theory of world-making—no single story that explains every planet around every star, or even the wildly divergent orbits orbiting our sun.The laws of physics are the same everywhere, but the process of building planets is sufficiently complicated that the system becomes chaotic says the scientists. 

Alessandro Morbidelli, an astronomer at the Cote in France, has devised influential theories about planet formation and migration.

Still, the findings are animating new research. Apart the chaos of world-building, patterns have emerged, leading astronomers toward powerful new ideas. Teams of researchers are working out the rules of dust and pebble assembly and how planets move once they coalesce. Fierce debate rages over the timing of each step, and over which factors determine a budding planet’s destiny. At the nexus of these debates are some of the oldest questions humans have asked ourselves: How did we get here? Is there anywhere else like here?

A Star and Its Acolytes Are Born.

Astronomers have understood the basic outlines of the solar system’s origins for nearly 300 years. The German philosopher Immanuel Kant, who like many Enlightenment thinkers dabbled in astronomy, published a theory in 1755 that remains pretty much correct. “All the matter making up the spheres belonging to our solar system, all the planets and comets, at the origin of all things was broken down into its elementary basic material

Indeed, we come from a diffuse cloud of gas and dust. Four and a half billion years ago, probably nudged by a passing star or by the shock wave of a supernova, the cloud collapsed under its own gravity to form a new star. It’s how things went down afterward that we don’t really understand.

Once the sun ignited, surplus gas swirled around it. Eventually, the planets formed there. The classical model that explained this, known as the minimum-mass solar nebula, envisioned a basic protoplanetary disk filled with just enough hydrogen, helium, and heavier elements to make the observed planets and asteroid belts. The model, which dates to 1977, assumed planets formed where we see them today, beginning as small “planetesimals,” then incorporating all the material in their area like locusts consuming every leaf in a field.

"The model was just somehow making this assumption that the solar disk was filled with planetesimals."

Writer- Meena Sripada