Readers ask about exoplanets, spider silk and water beetles

cover of August 27, 2020 issue

Faraway view

Astronomers snapped the first photo of a solar system with a sunlike star and two exoplanets, Lisa Grossman reported in “A weird solar system cousin makes its photographic debut” (SN: 8/29/20, p. 5).

“At the scale of the picture, both p­lanets — massive as they are — should appear as point sources, so I assume their spherical appearance is due to the light collection method for this direct imaging,” reader Jean Asselin wrote.

Asselin is correct that the system is so far away that scientists cannot physically resolve any of the planets, says Alexander Bohn, an astronomer at Leiden University in the Netherlands. Both of the planets have no spatial size as seen from Earth. “That both have a physical diameter in the image is just caused by the optical response of an imaging device to a point source,” Bohn says. “If you image the night sky with your smartphone camera, the stars also have a finite size of pixels in your image, even though they are point sources for both you and your smartphone.”


Some spider webs are coated in neurotoxins that may paralyze prey, Christie Wilcox reported in “Orb weavers may spin poisonous webs” (SN: 8/29/20, p. 18).

The story reminded reader Renata Riegler of a bit of medical folklore: S­pider webs were said to be used to dress wounds. “The paralyzing or antimicrobial properties … could have helped the healing,” Riegler wrote.

Spider webs may have been used for centuries to dress wounds. The practice even is mentioned in Shakespeare’s A Midsummer Night’s Dream: “I shall desire you of more acquaintance, good Master Cobweb: If I cut my finger, I shall make bold of you.” Spider silk is coated with chemicals that might promote blood clotting, prevent infection and speed healing, though scientific evidence for these properties is sparse, says associate editor Cassie Martin. Today, engineers are investigating spider silk as a drug delivery method and as scaffolding for tissue repair, she says.


A water beetle eaten by a pond frog scurried through the frog’s digestive tract and emerged out the backside unscathed, Jonathan Lambert reported in “Eaten beetle exits the other end alive” (SN: 8/29/20, p. 18). The story amazed readers on Twitter. @JoePoutous likened the beetle’s journey to the tunnel of t­error scene in the 1971 film Willy Wonka & the Chocolate Factory. @Rogie_The_Medic suggested a new name for the insect: fecal walking beetle.