"""Original conformal diagrams for unlimited and limited message exchanges.""" from pathlib import Path import matplotlib matplotlib.use('Agg') import matplotlib.pyplot as plt import numpy as np plt.rcParams.update({'font.size': 11, 'figure.facecolor': 'white', 'axes.facecolor': 'white'}) fig, axes = plt.subplots(1, 2, figsize=(9.2, 5.5), layout='constrained') for ax in axes: ax.set(xlim=(-0.18, 1.18), xticks=[0, 1], xticklabels=['Our galaxy', 'Other galaxy'], xlabel=r'Comoving position $x/\chi$') ax.axvline(0, color='#777777', lw=1) ax.axvline(1, color='#777777', lw=1) ax.grid(axis='y', alpha=0.2) ax.set_aspect(0.34) axes[0].set(ylim=(-0.15, 4.65), yticks=range(5), ylabel=r'Conformal time elapsed / $(\chi/c)$', title='Matter-only: unlimited future conformal time') for n in range(4): start, end = (0, 1) if n%2==0 else (1, 0) axes[0].annotate('', (end, n+1), (start, n), arrowprops={'arrowstyle': '->', 'lw': 2, 'color': '#16659c'}) b = 1-1/np.sqrt(2) axes[0].text(0.1, 0.13, r'$t_0$', fontsize=10) axes[0].text(0.13, 2.04, r'$t_2/t_0\approx3.988$', fontsize=10) axes[0].text(0.13, 4.08, r'$t_4/t_0\approx$'+f'{(1+4*b)**3:.2f}', fontsize=10) axes[0].annotate('Future continues', (0.5, 4.6), (0.5, 4.3), ha='center', arrowprops={'arrowstyle': '->', 'color': '#777777'}, fontsize=10) ax=axes[1] ax.set(ylim=(-0.15, 4.65), yticks=[0, 1, 1.6, 2, 3, 4], title=r'Persistent $\Lambda>0$: finite future interval') ax.axhspan(1.6, 4.65, color='#eeeeee') ax.axhline(1.6, color='#b22428', ls='--', lw=1.7) ax.annotate('', (1, 1), (0, 0), arrowprops={'arrowstyle': '->', 'lw': 2, 'color': '#16659c'}) ax.annotate('', (0.4, 1.6), (1, 1), arrowprops={'arrowstyle': '->', 'lw': 2, 'color': '#b45b14'}) ax.text(0.5, 2.0, 'Future conformal boundary\n(at infinite cosmic time)', ha='center', fontsize=10) ax.text(0.5, 3.15, 'Illustrative remaining interval: 1.6\nOne outward leg fits.\nA two-leg round trip cannot fit.', ha='center', va='center', fontsize=10) ax.text(0.13, 0.14, 'Send now', fontsize=9) ax.text(0.35, 1.02, 'Immediate reply', fontsize=9, color='#99480a') fig.suptitle('Signal paths are straight in conformal coordinates', fontsize=14) fig.savefig(Path.cwd()/Path(__file__).with_suffix('.png').name, dpi=150, facecolor='white', transparent=False) plt.close(fig)