Griffith Observatory

ABSTRACT We present the characteristics of interstellar comet 3I/Asteroid Terrestrial-impact Last Alert System (ATLAS), discovered on 2025 July 1 by the ATLAS. The comet has eccentricity $\simeq$6.1 and velocity at infinity $\simeq$57 km s−1, indicating an interstellar origin. We obtained B, V, R, I, g, r, i, and z photometry at Kottamia Astronomical Observatory, Palomar Observatory, and Apache Point Observatory on 2025 July 2, 3, and 6. We measured colour indices B–V = 0.98 $\pm$ 0.23, V–R = 0.71 $\pm$ 0.09, R–I = 0.14 $\pm$ 0.10, g–r = 0.84 $\pm$ 0.05, r–i = 0.16$\pm$0.03, i–z = –0.02$\pm$0.07, g–i = 1.00$\pm$0.05, and a spectral slope of 16.0 $\pm$ 1.9 ${{\ \rm per\ cent}}$/100 nm. We estimate the comet’s dust cross-section within 10 000 km to be 184.6 $\pm$ 4.6 km$^2$, assuming a 0.1 albedo. 3I/ATLAS’s coma has full width at half-maximum $\simeq$ 2.2 arcsec and A(0$^\circ$)f$\rho$ = 280.8 $\pm$ 3.2 cm. We estimate 3I/ATLAS is ejecting $\mu$m to mm dust at $\sim$0.01–1 m s−1, with a mass-loss of $\sim$0.1–1.0 kg s−1.

Abstract We describe observations and physical characteristics of Earth-crossing asteroid 2024 YR4, discovered on 2024 December 27 by the Asteroid Terrestrial-impact Last Alert System. The asteroid has semimajor axis a = 2.52 au, eccentricity e = 0.66, inclination i = 3 . ° 41, and a ∼0.003 au Earth minimum orbit intersection distance. We obtained g-, r-, i-, and Z-imaging with the Gemini South/Gemini Multi-Object Spectrograph on 2025 February 7 and Y and J imaging with the Keck/Multi-Object Spectrometer for Infrared Exploration on 2025 February 12. We measured a g − i spectral slope of 13% ± 3%/100 nm and color indices g −​ r = 0.70 ± 0.10, r − i = 0.25 ± 0.06, i − Z = −0.27 ± 0.10, and Y − J = 0.41 ± 0.10. 2024 YR4 has a spectrum that best matches R-type and Sa-type asteroids and a diameter of ∼30–65 m using our measured absolute magnitude of 23.9 ± 0.3 mag and assuming an albedo of 0.15–0.4. The lightcurve of 2024 YR4 shows ∼0.4 mag variations with a rotation period of ∼1170 s. We use photometry of 2024 YR4 from Gemini and other sources taken between 2024 December to 2025 February to determine the asteroid’s spin vector and shape, finding that it has an oblate, ∼3:1 axial ratio and a pole direction of λ, β = ∼ 42∘, ∼−25∘. Finally, we compare the orbital elements of 2024 YR4 with the near-Earth object population model and find that its most likely sources are resonances between the inner and central Main Belt.

Evidence of systematic astronomical observation and the impact of celestial knowledge on culture is plentiful in the Bronze Age societies of Egypt, Mesopotamia and Europe. An interest in astral phenomena is also reflected in Hittite documents, architecture and art. The rock-cut reliefs of 64 deities in the main chamber of Yazilikaya, a Hittite rock sanctuary associated with Hattusa, the Hittite capital in central Anatolia, can be broken into groups marking days, synodic months and solar years. Here, we suggest that the sanctuary in its entirety represents a symbolic image of the cosmos, including its static levels (earth, sky, underworld) and the cyclical processes of renewal and rebirth (day/night, lunar phases, summer/winter). Static levels and celestial cyclicities are emphasised throughout the sanctuary – every single relief relates to this system. We interpret the central panel with the supreme deities, at the far north end of Chamber A, as a reference to the northern stars, the circumpolar realm and the world axis. Chamber B seems to symbolise the netherworld.

There was a time when science and the occult happily coexisted under the same roof, one scarcely discernible from the other in method and practice. This is the story of how they parted company, and why one was relegated to the darker side of history while the other has come to bask in the limelight of mainstream belief. From astrology to divination, and alchemy to spoon-bending, thee book is an examination of magic and its scientific bases, and of magical phenomena. The personalities caught up in the intersection of superstition include Emmanuel Swedenborg, Madame Blavatsky, Aleister Crowley and Harry Houdini.