THE SOUTHWORTH PLANETARIUM 70 Falmouth Street Portland, Maine 04103 (207) 780-4249 usm.maine.edu/planet 43.6667° N 70.2667° W Altitude: 10 feet below sea level Founded January 1970 2021-2022: LXXI "The gift of fantasy has meant more to me than my talent for absorbing positive knowledge." - Albert Einstein THE DAILY ASTRONOMER Tuesday, January 25, 2022 The Interstellar Probe Cosmic News Flash to enliven your Tuesday afternoon: NASA could launch its first interstellar probe as early as 2036! Though this yet-to-be-named vessel is still just in the "study phase," Jet Propulsion Laboratory scientists have announced that plans could soon be underway for the construction and deployment of a probe that will embark on a half-century long mission to regions far beyond the reach of any previously launched spacecraft. Unfortunately, despite the "interstellar" label, this ship isn't exactly going to be like the USS Enterprise darting between star systems to interact with English-speaking aliens with sensitive souls and perfect hair. Instead, it would be designed to remain operational out to a distance of 350 - 1000 AU. An Astronomical Unit is defined as the mean separation distance between Earth and the Sun, equal to about 93,000 million miles. To put that admittedly impressive distance into perspective, however, Alpha Centauri, the closest star to the Sun, is 268,172 AU away. The mission's aim is to study the region behind the heliosphere, the "bubble" where the solar wind interacts with interstellar particles. The Voyager craft infiltrated this region about a decade ago. Yet, as their on-board instrucmentation was designed to survey planets, the information they've been able to gather about this rarefied region has been scant. The Interstellar Probe's primary aim is to examine the conditions along and beyond this bubble.* Such scrutiny is timely as the solar system will soon be exiting the "local interstellar cloud," a tenous gaseous body through which we've been traveling for the last 60,000 years. Conditions outside this cloud should be profoundly different from those that currently prevail along the solar system's outer regions. Even though the planned mission duration could equal or exceed fifty to a hundred years, great speed will be required to propel it to this distance. Attaining such velocities require super heavy launch vehicles that could, in conjunction with the occasional gravitational slingshot around an outer planet, push the probe along at the astonishing speed of 7 - 8 AU a year. (Approximately 85,000 miles per hour!) Such launch vehicles will soon come on-line, making an interstellar probe deployment far more feasible. All the same, unlike other missions, this one will require the cooperation of more than one generation of scientists. Those researches involved in the initial stages will likely be retired or will have moved on by the time the mission reaches its conclusion. It is akin to the construction of Stonehenge in a way. As the completion of that famous megalithic structure likely required many centuries, most of those involved in its development labored under the apprehension that the project would be done long after deaths. Despite having been denied the gratification of seeing the finished project, they still worked earnestly on it. One could say that humans have always found inspiration in enterprises far larger than themselves. The legions of Stonehenge builders might not have needed to see it done, but, instead, wanted to be a small part of such a grand endeavor. Five thousand years later, as we prepare to take our next tentative steps into the unbounded black, many generations will work in concert toward the next advancement. *While en route, it could pass by a few of the myriad dwarf worlds scattered around the Kuiper Belt region. To subscribe or unsubscribe from the Daily Astronomer: https://lists.maine.edu/cgi-bin/wa?SUBED1=DAILY-ASTRONOMER&A=1