Eridanus

Chee Lan's home planet, Lifehome-under-Sky/Cynthia, is O2 Eridani A II. I think that "Eridani A II" would mean "the second planet of the first star in the constellation, Eridanus" but I do not know what the "O2" means. (That is meant to be a small 2 to the lower right of the O.)

Googling "Eridanus," I learned that:

there is an Eridanus supervoid;

filaments of gravitationally bound galaxies are the largest known structures in the universe and form the boundaries of voids.

I did not know any of that.

Poul Anderson speculated about trans-galactic cosmic structures in Tau Zero and World Without Stars. See here. But he did not know about filaments or voids.

Moving Planets

"Men can alter a world, or ruin one; but they cannot move it one centimeter off its ordained course. That requires energies of literally cosmic magnitude.
"So you couldn't ease this planet into a suitable orbit around Beta Crucis. It must continue its endless wanderings."
-Poul Anderson, Satan's World IN Anderson, David Falkayn: Star Trader (Riverdale, NY, 2010), pp. 329-598 AT p. 357.

Would gravity control not allow the moving of planets? In James Blish's Cities In Flight, men move a planet between galaxies faster than light with graviton polarity generators. In Olaf Stapledon's Star Maker, the telepathic galactic mind launches a star cluster between galaxies.

Satan, the planet passing close to Beta Crucis, is a rogue. It seems that Anderson is correct when he tells us that there are many such planets. Satan's cryosphere becomes atmosphere and hydrosphere at periastron passage but re-forms during recession.

"'Nothing basic would have happened.'"
-op. cit., p. 356.

- except that the planet can be put to massive industrial use while it is energized. Satan and Mirkheim are two amazing creations by Anderson and the latter idea was suggested by his editor, John W. Campbell.

London And Luna

In Flandry And Leamas, we compared Poul Anderson's Dominic Flandry with John le Carre's Alec Leamas. Now we find a lesser parallel between Anderson's David Falkayn and Leamas.

Both London and Luna are in the cosmos although we do do not think of London as a "cosmic environment."

In London, to evade any followers, Leamas:

suddenly jumps on a bus to Ludgate Hill;
dismounts in a traffic jam;
catches a tube;
stands in the end carriage;
alights at the next station;
catches another train to Euston;
goes back to Charing Cross, where a van waits in the forecourt.

On Luna, to evade any followers, Falkayn:

passes through a large sporting goods store;
walks behind large items;
leaves by a rear door;
finds a kiosk;
enters the antigrav dropshaft;
gets off at the eighth sublevel;
proceeds along the corridors to his destination.

In one of his novels, Frederick Forsyth explains how a trained team can follow anyone without being spotted and not lose him. Anyone who turns a corner, runs to the next corner and looks back merely alerts the team that he thinks he might be followed.

On The Planet Lucifer II

See On The Planet Lucifer.

Quetlan and Laura, the suns of Ythri and Avalon respectively, are in the constellation Lupus.

Coya, astrophysicist and frequent space traveler, is at home in the universe, able to identify the brightest stars among the rest. The Dewfall has traveled at high speed for nearly a month from Quetlan towards the Deneb sector. Since Quetlan is 278 light years from Sol towards Lupus, they are now a hundred parsecs from Earth in unknown space. Coya knows this. To that extent, she is as at home there as a Londoner is in Hyde Park. The universe is our home and we ought to be one with it.
-copied from here.

We first read of Avalon in Hloch's Introduction to "The Problem of Pain," then in a conversation on Lucifer:

The planet Lucifer is inhospitable but might be marginally habitable and has mineral wealth. Both days and nights are long, storms are frequent, there is no green vegetation and the violent blue sun continually disrupts electronics. A uranium-concentrating root causes a unique ecological cycle in one area.
-copied from here.

I am rereading the relevant passages of "The Problem of Pain" for any more information about Lucifer. The narrator tells us that the planet is well named. However, if it proves to be even marginally habitable, then its mineral wealth will be worth exploiting. The exploratory team must determine whether the survival problems can be solved economically. Furious day-time weather ends in a twilight gale. Storms blow dust. The air is thin. Auroras flame. Frost covers the land and glittering ice sheathes twisted "trees."

When, in the concluding sentence, the sun rises from the burning horizon, I think that this is an appropriate pathetic fallacy for the theme of the story. See here.

Unusual Iapetus

In Poul Anderson's "The Saturn Game," less than a thousand years ago, a comet swung round Saturn and struck Iapetus, covering one hemisphere with ice, including the "City of Ice" glacier composed of the differently colored ices of diverse materials, water, ammonia, methane, carbon dioxide etc. Landing meteorites collect solar heat and melt their surroundings. The properties of the different ices produce not smooth craters but fantastic concavities. Anderson goes into more detail than I can summarize here.

The upshot is that this Saturnian moon becomes yet another of Poul Anderson's "Unusual Heavenly Bodies." See here.