Science1 distinct publisher3 min readPublished
Stefan Gillessen's group pulled S301 out of Very Large Telescope monitoring begun in 2023, and its perihelion of twelve astronomical units sits close enough that frame dragging should register in the orbit after roughly another decade of tracking.
The Scientist · Science desk
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Frame dragging is the piece of general relativity with no Newtonian counterpart. A rotating mass does not only curve space-time, it winds it, and orbits inside the wound region are slowly twisted along with it [7]. Earth does this too, faintly enough that satellites are needed to detect it, as Tuan Do at UCLA, who was not involved in the work, points out [8]. Black holes are harder, because there is no visible surface to watch rotate, which leaves frame dragging as the most precise handle on spin and makes S301 the first star close enough to offer one [9]. Gillessen's own image for it is a leaf dropped into the wind to read how the air is moving [14].
The distances repay checking by hand. A closest approach of 1.8 billion kilometres, described as twelve times the Earth-sun distance, works out to 150 million kilometres per astronomical unit, which is the astronomical unit, so those two figures are one measurement stated twice [1]. Ten times further out puts the previous record-holder near 120 astronomical units, about 18 billion kilometres [2]. The peak speed, above 8 per cent of light, is roughly 24,000 kilometres per second [3]. Gillessen says that from a planet around S301, the black hole at closest approach would appear about the size of the full moon seen from Earth [6].
Getting spin out of that orbit is slower work. Gillessen puts it at about a decade of further tracking [10]. Ziri Younsi at University College London frames the yield carefully: one star would take a while but would still be by far the best constraint on spin obtained to date, a closer star would be better, and a population of them would put the whole programme on a different footing [11]. Gillessen's team has several candidates slightly further out than S301, and none yet closer [12].
This orbit makes the spin measurement possible, but has not yet produced it. The New Scientist account does not give the star's orbital period, so how many close passes fall inside Gillessen's decade is not on the record [16], and the word Younsi uses for the outcome is constraint [11].
That still matters, because the behaviour of gravity in extreme environments has been very difficult to study, and this would be a direct probe of it [15]. On the evidence I would call the galactic centre the best strong-field gravity laboratory currently accessible, with one condition attached: the case rests on continued astrometry of a single faint, fast star, using a telescope in Chile that was already in service when the monitoring started in 2023 [2][3], and the binding resource is calendar time on an instrument already in service.
Ranked by verification strength, evidence, and original report placement.
At its closest approach S301 is only about 1.8 billion kilometres from Sagittarius A*, the supermassive black hole at the centre of the Milky Way, or twelve times the distance between Earth and the sun.
That closest approach is ten times closer to Sagittarius A* than the previous record-holding star.
A star named S301 near the centre of the Milky Way has a peak orbital speed of more than 8 per cent of the speed of light, making it both the fastest star and the closest to a supermassive black hole ever spotted.
Stefan Gillessen at the Max Planck Institute for Extraterrestrial Physics in Germany and his colleagues found S301 using the Very Large Telescope in Chile.
The team has been watching S301 since 2023 to gather enough data to pin down its orbit.
Gillessen says that from a planet orbiting this star, the black hole at closest approach would appear similar in size to the full moon seen from Earth.
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1 article · August 28, 2026
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Evidence-backed comparisons of source perspectives and observed adoption signals. Read the methodology
Which Builder, Operator, and Investor concerns the observed source mix emphasized—not a truth score.
Evidence, demonstrated adoption, hype gap, incentives, and confidence are assessed independently, each on its own current evidence. How these are measured.
Named sources, single thread, no orbit on the table
Everything traces to one New Scientist report with no paper, preprint or orbital solution behind it. What holds it up is that the people are named and two of them stand outside the work: Tuan Do explains that Earth's own frame dragging is already measured with satellites, and Ziri Younsi grades what one star versus a population would buy. The internal numbers are consistent — 1.8 billion kilometres and twelve times the Earth-sun distance are the same fact stated twice. What is missing is anything a reader could recompute from: no period, no eccentricity, no uncertainties, and no named predecessor for the record S301 supposedly breaks tenfold.
No independent confirmation to point at
For a result like this, uptake means another group re-deriving the orbit or a second instrument seeing the same star — and nothing of the sort appears in what we have. The monitoring is the discovery team's own, on one telescope, and the spin measurement it is meant to enable has not happened. We would rather leave this blank than present a single observing campaign as traction.
Superlatives on top, patience underneath
The gap sits in the packaging rather than the substance. Headline records and Gillessen's quip about a call from Stockholm in twenty years front a body of text that concedes the spin measurement is about a decade of further tracking away, that no closer star has been found, and that the candidates in hand are further out. New Scientist does not bury the wait; it simply leads with the record and lets the Nobel line close things out.
The finder does most of the talking
Four of the quotes belong to the man whose group found the star, and he is the one who raises the 2020 Nobel and mentions further candidates still to be nailed down — exactly the case a team makes when it needs another decade of telescope time. Do and Younsi pull the other way by being outside the research, though both work in a field that gains if Sagittarius A* becomes the place where spin finally gets measured.
Solid on the star, shaky on the schedule
One publisher, no primary document, and a central promise no one can test until years of additional tracking exist. We are reasonably comfortable repeating what S301's speed and perihelion are said to be; we are much less comfortable saying how firm the ten-year path to a spin measurement is.