What Would Happen If We Were About 1 pc Away from a Supermassive Black
  Hole?
  We consider a hypothetical planet with the same mass $m$, radius $R$, angular
momentum $\boldsymbol{S}$, oblateness $J_2$, semimajor axis $a$, eccentricity
$e$, inclination $I$, and obliquity $\varepsilon$ of the Earth orbiting a
main-sequence star with the same mass $M_\star$ and radius $R_\star$ of the Sun
at a distance $r_\bullet \simeq 1\,\mathrm{parsec}\,\left(\mathrm{pc}\right)$
from a supermassive black hole in the center of the hosting galaxy with the
same mass $M_\bullet$ of, say, $\mathrm{M87}^\ast$. We preliminarily
investigate some dynamical consequences of its presence in the neighborhood of
such a stellar system on the planet's possibility of sustaining complex life
over time. In particular, we obtain general analytic expressions for the
long-term rates of change, doubly averaged over both the planetary and the
galactocentric orbital periods $P_\mathrm{b}$ and $P_\bullet$, of
$e,\,I,\,\varepsilon$, which are the main quantities directly linked to the
stellar insolation. We find that, for certain orbital configurations, the
planet's perihelion distance $q=a\left(1-e\right)$ may greatly shrink and lead
to, in some cases, an impact with the star. $I$ may also notably change, with
variations even of the order of tens of degrees. On the other hand,
$\varepsilon$ does not seem to be particularly affected, being shifted, at
most, by $\simeq 0^\circ.02$ over 1 Myr. Our results strongly depend on the
eccentricity $e_\bullet$ of the galactocentric motion.
